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Process.Start Method

  • Reference

Definition

Namespace:
System.Diagnostics
Assembly:
System.Diagnostics.Process.dll
Assembly:
System.dll
Assembly:
netstandard.dll

Starts a process resource and associates it with a Process component.

Overloads

Start(String, String, String, SecureString, String)

Starts a process resource by specifying the name of an application, a set of command-line arguments, a user name, a password, and a domain and associates the resource with a new Process component.
Start(String, String, SecureString, String)

Starts a process resource by specifying the name of an application, a user name, a password, and a domain and associates the resource with a new Process component.
Start(String, String)

Starts a process resource by specifying the name of an application and a set of command-line arguments, and associates the resource with a new Process component.
Start(String)

Starts a process resource by specifying the name of a document or application file and associates the resource with a new Process component.
Start(ProcessStartInfo)

Starts the process resource that is specified by the parameter containing process start information (for example, the file name of the process to start) and associates the resource with a new Process component.
Start()

Starts (or reuses) the process resource that is specified by the StartInfo property of this Process component and associates it with the component.
Start(String, IEnumerable<String>)

Starts a process resource by specifying the name of an application and a set of command line arguments.

Start(String, String, String, SecureString, String)

Source:
Process.Unix.cs
Source:
Process.Unix.cs
Source:
Process.Unix.cs

Important

This API is not CLS-compliant.

Starts a process resource by specifying the name of an application, a set of command-line arguments, a user name, a password, and a domain and associates the resource with a new Process component.

public:
 static System::Diagnostics::Process ^ Start(System::String ^ fileName, System::String ^ arguments, System::String ^ userName, System::Security::SecureString ^ password, System::String ^ domain);
[System.CLSCompliant(false)]
[System.Runtime.Versioning.SupportedOSPlatform("windows")]
public static System.Diagnostics.Process? Start (string fileName, string arguments, string userName, System.Security.SecureString password, string domain);
[System.CLSCompliant(false)]
public static System.Diagnostics.Process Start (string fileName, string arguments, string userName, System.Security.SecureString password, string domain);
public static System.Diagnostics.Process Start (string fileName, string arguments, string userName, System.Security.SecureString password, string domain);
[<System.CLSCompliant(false)>]
[<System.Runtime.Versioning.SupportedOSPlatform("windows")>]
static member Start : string * string * string * System.Security.SecureString * string -> System.Diagnostics.Process
[<System.CLSCompliant(false)>]
static member Start : string * string * string * System.Security.SecureString * string -> System.Diagnostics.Process
static member Start : string * string * string * System.Security.SecureString * string -> System.Diagnostics.Process
Public Shared Function Start (fileName As String, arguments As String, userName As String, password As SecureString, domain As String) As Process

Parameters

fileName
String

The name of an application file to run in the process.

arguments
String

Command-line arguments to pass when starting the process.

userName
String

The user name to use when starting the process.

password
SecureString

A SecureString that contains the password to use when starting the process.

domain
String

The domain to use when starting the process.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that's started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Attributes
CLSCompliantAttribute SupportedOSPlatformAttribute

Exceptions

InvalidOperationException

No file name was specified.

Win32Exception

An error occurred when opening the associated file.

-or-

The file specified in the fileName could not be found.

-or-

The sum of the length of the arguments and the length of the full path to the associated file exceeds 2080. The error message associated with this exception can be one of the following: "The data area passed to a system call is too small." or "Access is denied."

ObjectDisposedException

The process object has already been disposed.

PlatformNotSupportedException

This member is not supported on Linux or macOS (.NET Core only).

Remarks

Use this overload to create a new process and its primary thread by specifying its file name, command-line arguments, user name, password, and domain. The new process then runs the specified executable file in the security context of the specified credentials (user, domain, and password).

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Note

When the executable file is located on a remote drive, you must identify the network share by using a uniform resource identifier (URI), not a linked drive letter.

Note

If the address of the executable file to start is a URL, the process is not started and null is returned.

This overload lets you start a process without first creating a new Process instance. The overload is an alternative to the explicit steps of creating a new Process instance, setting the FileName, Arguments, UserName, Password, and Domain properties of the StartInfo property, and calling Start for the Process instance.

Similarly, in the same way that the Run dialog box can accept an executable file name with or without the .exe extension, the .exe extension is optional in the fileName parameter. For example, you can set the fileName parameter to either "Notepad.exe" or "Notepad". If the fileName parameter represents an executable file, the arguments parameter might represent a file to act upon, such as the text file in Notepad.exe myfile.txt.

Note

The file name must represent an executable file in the Start overloads that have userName, password, and domain parameters.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

Applies to

Start(String, String, SecureString, String)

Source:
Process.Unix.cs
Source:
Process.Unix.cs
Source:
Process.Unix.cs

Important

This API is not CLS-compliant.

Starts a process resource by specifying the name of an application, a user name, a password, and a domain and associates the resource with a new Process component.

public:
 static System::Diagnostics::Process ^ Start(System::String ^ fileName, System::String ^ userName, System::Security::SecureString ^ password, System::String ^ domain);
[System.CLSCompliant(false)]
[System.Runtime.Versioning.SupportedOSPlatform("windows")]
public static System.Diagnostics.Process? Start (string fileName, string userName, System.Security.SecureString password, string domain);
[System.CLSCompliant(false)]
public static System.Diagnostics.Process Start (string fileName, string userName, System.Security.SecureString password, string domain);
public static System.Diagnostics.Process Start (string fileName, string userName, System.Security.SecureString password, string domain);
[<System.CLSCompliant(false)>]
[<System.Runtime.Versioning.SupportedOSPlatform("windows")>]
static member Start : string * string * System.Security.SecureString * string -> System.Diagnostics.Process
[<System.CLSCompliant(false)>]
static member Start : string * string * System.Security.SecureString * string -> System.Diagnostics.Process
static member Start : string * string * System.Security.SecureString * string -> System.Diagnostics.Process
Public Shared Function Start (fileName As String, userName As String, password As SecureString, domain As String) As Process

Parameters

fileName
String

The name of an application file to run in the process.

userName
String

The user name to use when starting the process.

password
SecureString

A SecureString that contains the password to use when starting the process.

domain
String

The domain to use when starting the process.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that's started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Attributes
CLSCompliantAttribute SupportedOSPlatformAttribute

Exceptions

InvalidOperationException

No file name was specified.

Win32Exception

There was an error in opening the associated file.

-or-

The file specified in the fileName could not be found.

ObjectDisposedException

The process object has already been disposed.

PlatformNotSupportedException

This member is not supported on Linux or macOS (.NET Core only).

Examples

The following code example shows the use of this overload to start an executable file and also demonstrates the throwing of a Win32Exception when an attempt is made to start an application associated with a nonexecutable file.

// NOTE: This example requires a text.txt file file in your Documents folder
using System;
using System.Diagnostics;
using System.Security;
using System.ComponentModel;

class Example
{
    static void Main()
    {
        Console.Write("Enter your domain: ");
        string domain = Console.ReadLine();
        Console.Write("Enter you user name: ");
        string uname = Console.ReadLine();
        Console.Write("Enter your password: ");
        SecureString password = new SecureString();
        ConsoleKeyInfo key;
        do
        {
            key = Console.ReadKey(true);

            // Ignore any key out of range.
            if (((int)key.Key) >= 33 && ((int)key.Key <= 90) && key.Key != ConsoleKey.Enter)
            {
                // Append the character to the password.
                password.AppendChar(key.KeyChar);
                Console.Write("*");
            }
            // Exit if Enter key is pressed.
        } while (key.Key != ConsoleKey.Enter);
        Console.WriteLine();

        try
        {
            Console.WriteLine("\nTrying to launch NotePad using your login information...");
            Process.Start("notepad.exe", uname, password, domain);
        }
        catch (Win32Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        string path = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\\";

        try
        {
            // The following call to Start succeeds if test.txt exists.
            Console.WriteLine("\nTrying to launch 'text.txt'...");
            Process.Start(path + "text.txt");
        }
        catch (Win32Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        try
        {
            // Attempting to start in a shell using this Start overload fails. This causes
            // the following exception, which is picked up in the catch block below:
            // The specified executable is not a valid application for this OS platform.
            Console.WriteLine("\nTrying to launch 'text.txt' with your login information...");
            Process.Start(path + "text.txt", uname, password, domain);
        }
        catch (Win32Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
        finally
        {
            password.Dispose();
        }
    }
}

// NOTE: This example requires a text.txt file file in your Documents folder
open System
open System.Diagnostics
open System.Security
open System.ComponentModel

printf "Enter your domain: "
let domain = stdin.ReadLine()
printf "Enter you user name: "
let uname = stdin.ReadLine()
printf "Enter your password: "
let password = new SecureString()

let mutable key = Console.ReadKey(true)

while key.Key <> ConsoleKey.Enter do
    // Ignore any key out of range.
    if int key.Key >= 33 && int key.Key <= 90 && key.Key <> ConsoleKey.Enter then
        // Append the character to the password.
        password.AppendChar key.KeyChar
        Console.Write "*"

    key <- Console.ReadKey(true)

printfn ""

try
    printfn "\nTrying to launch NotePad using your login information..."
    Process.Start("notepad.exe", uname, password, domain) |> ignore
with :? Win32Exception as ex ->
    printfn $"{ex.Message}"

let path = Environment.GetFolderPath Environment.SpecialFolder.MyDocuments + @"\"

try
    // The following call to Start succeeds if test.txt exists.
    printfn "\nTrying to launch 'text.txt'..."
    Process.Start $"{path}text.txt" |> ignore
with :? Win32Exception as ex ->
    printfn $"{ex.Message}"

try
    try
        // Attempting to start in a shell using this Start overload fails. This causes
        // the following exception, which is picked up in the catch block below:
        // The specified executable is not a valid application for this OS platform.
        printfn "\nTrying to launch 'text.txt' with your login information..."
        Process.Start($"{path}text.txt", uname, password, domain) |> ignore
    with :? Win32Exception as ex ->
        printfn $"{ex.Message}"
finally
    password.Dispose()

' This sample requires a text.txt file file in your documents folder.
' You'll also need to set the startup object in the project to Sub Main.
Imports System.Diagnostics
Imports System.Security
Imports System.ComponentModel

Module Program
    Sub Main()
        Console.Write("Enter your domain: ")
        Dim domain As String = Console.ReadLine()
        Console.Write("Enter you user name: ")
        Dim uname As String = Console.ReadLine()
        Console.Write("Enter your password: ")
        Dim password As New SecureString()
        Dim key As ConsoleKeyInfo
        Do
            key = Console.ReadKey(True)

            ' Ignore any key out of range.
            If key.Key >= 33 AndAlso key.Key <= 90 AndAlso key.Key <> ConsoleKey.Enter Then
                ' Append the character to the password.
                password.AppendChar(key.KeyChar)
                Console.Write("*")
            End If
            ' Exit if Enter key is pressed.
        Loop While key.Key <> ConsoleKey.Enter
        Console.WriteLine()

        Try
            Console.WriteLine(vbCrLf + "Trying to launch NotePad using your login information...")
            Process.Start("notepad.exe", uname, password, domain)
        Catch ex As Win32Exception
            Console.WriteLine(ex.Message)
        End Try

        Dim path As String = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\"

        Try
            ' The following call to Start succeeds if test.txt exists.
            Console.WriteLine(vbCrLf + "Trying to launch 'text.txt'...")
            Process.Start(path + "Text.txt")
        Catch ex As Win32Exception
            Console.WriteLine(ex.Message)
        End Try

        Try
            ' Attempting to start in a shell using this Start overload fails. This causes
            ' the following exception, which is picked up in the catch block below:
            ' The specified executable is not a valid application for this OS platform.
            Console.WriteLine(vbCrLf + "Trying to launch 'text.txt' with your login information...")
            Process.Start(path + "Text.txt", uname, password, domain)
        Catch ex As Win32Exception
            Console.WriteLine(ex.Message)
        Finally
            password.Dispose()
        End Try
    End Sub
End Module

Remarks

Use this overload to create a new process and its primary thread by specifying its file name, user name, password, and domain. The new process then runs the specified executable file in the security context of the specified credentials (user, domain, and password).

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Note

When the executable file is located on a remote drive, you must identify the network share by using a uniform resource identifier (URI), not a linked drive letter.

Note

If the address of the executable file to start is a URL, the process is not started and null is returned.

This overload lets you start a process without first creating a new Process instance. The overload is an alternative to the explicit steps of creating a new Process instance, setting the FileName, UserName, Password, and Domain properties of the StartInfo property, and calling Start for the Process instance.

Similarly, in the same way that the Run dialog box can accept an executable file name with or without the .exe extension, the .exe extension is optional in the fileName parameter. For example, you can set the fileName parameter to either "Notepad.exe" or "Notepad". If the fileName parameter represents an executable file, the arguments parameter might represent a file to act upon, such as the text file in Notepad.exe myfile.txt.

Note

The file name must represent an executable file in the Start overloads that have userName, password, and domain parameters.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

Applies to

Start(String, String)

Source:
Process.cs
Source:
Process.cs
Source:
Process.cs

Starts a process resource by specifying the name of an application and a set of command-line arguments, and associates the resource with a new Process component.

public:
 static System::Diagnostics::Process ^ Start(System::String ^ fileName, System::String ^ arguments);
public static System.Diagnostics.Process Start (string fileName, string arguments);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static System.Diagnostics.Process Start (string fileName, string arguments);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
[System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
public static System.Diagnostics.Process Start (string fileName, string arguments);
static member Start : string * string -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
static member Start : string * string -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
[<System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")>]
static member Start : string * string -> System.Diagnostics.Process
Public Shared Function Start (fileName As String, arguments As String) As Process

Parameters

fileName
String

The name of an application file to run in the process.

arguments
String

Command-line arguments to pass when starting the process.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that's started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Attributes
UnsupportedOSPlatformAttribute SupportedOSPlatformAttribute

Exceptions

InvalidOperationException

The fileName or arguments parameter is null.

Win32Exception

An error occurred when opening the associated file.

-or-

The file specified in the fileName could not be found.

-or-

The sum of the length of the arguments and the length of the full path to the process exceeds 2080. The error message associated with this exception can be one of the following: "The data area passed to a system call is too small." or "Access is denied."

ObjectDisposedException

The process object has already been disposed.

FileNotFoundException

The PATH environment variable has a string containing quotes.

Examples

The following example first spawns an instance of Internet Explorer and displays the contents of the Favorites folder in the browser. It then starts some other instances of Internet Explorer and displays some specific pages or sites. Finally it starts Internet Explorer with the window being minimized while navigating to a specific site.

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;
using namespace System::ComponentModel;

// Opens the Internet Explorer application.
void OpenApplication(String^ myFavoritesPath)
{
    // Start Internet Explorer. Defaults to the home page.
    Process::Start("IExplore.exe");

    // Display the contents of the favorites folder in the browser.
    Process::Start(myFavoritesPath);
}

// Opens urls and .html documents using Internet Explorer.
void OpenWithArguments()
{
    // URLs are not considered documents. They can only be opened
    // by passing them as arguments.
    Process::Start("IExplore.exe", "www.northwindtraders.com");

    // Start a Web page using a browser associated with .html and .asp files.
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.htm");
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.asp");
}

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
void OpenWithStartInfo()
{
    ProcessStartInfo^ startInfo = gcnew ProcessStartInfo("IExplore.exe");
    startInfo->WindowStyle = ProcessWindowStyle::Minimized;
    Process::Start(startInfo);
    startInfo->Arguments = "www.northwindtraders.com";
    Process::Start(startInfo);
}

int main()
{
    // Get the path that stores favorite links.
    String^ myFavoritesPath = Environment::GetFolderPath(Environment::SpecialFolder::Favorites);
    OpenApplication(myFavoritesPath);
    OpenWithArguments();
    OpenWithStartInfo();
}

using System;
using System.Diagnostics;
using System.ComponentModel;

namespace MyProcessSample
{
    class MyProcess
    {
        // Opens the Internet Explorer application.
        void OpenApplication(string myFavoritesPath)
        {
            // Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe");

            // Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath);
        }

        // Opens urls and .html documents using Internet Explorer.
        void OpenWithArguments()
        {
            // url's are not considered documents. They can only be opened
            // by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com");

            // Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.htm");
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.asp");
        }

        // Uses the ProcessStartInfo class to start new processes,
        // both in a minimized mode.
        void OpenWithStartInfo()
        {
            ProcessStartInfo startInfo = new ProcessStartInfo("IExplore.exe");
            startInfo.WindowStyle = ProcessWindowStyle.Minimized;

            Process.Start(startInfo);

            startInfo.Arguments = "www.northwindtraders.com";

            Process.Start(startInfo);
        }

        static void Main()
        {
            // Get the path that stores favorite links.
            string myFavoritesPath =
                Environment.GetFolderPath(Environment.SpecialFolder.Favorites);

            MyProcess myProcess = new MyProcess();

            myProcess.OpenApplication(myFavoritesPath);
            myProcess.OpenWithArguments();
            myProcess.OpenWithStartInfo();
        }
    }
}

module processstartstatic

open System
open System.Diagnostics

// Opens the Internet Explorer application.
let openApplication (myFavoritesPath: string) =
    // Start Internet Explorer. Defaults to the home page.
    Process.Start "IExplore.exe" |> ignore

    // Display the contents of the favorites folder in the browser.
    Process.Start myFavoritesPath |> ignore

// Opens urls and .html documents using Internet Explorer.
let openWithArguments () =
    // url's are not considered documents. They can only be opened
    // by passing them as arguments.
    Process.Start("IExplore.exe", "www.northwindtraders.com") |> ignore

    // Start a Web page using a browser associated with .html and .asp files.
    Process.Start("IExplore.exe", @"C:\myPath\myFile.htm") |> ignore
    Process.Start("IExplore.exe", @"C:\myPath\myFile.asp") |> ignore

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
let openWithStartInfo () =
    let startInfo = ProcessStartInfo "IExplore.exe"
    startInfo.WindowStyle <- ProcessWindowStyle.Minimized

    Process.Start startInfo |> ignore

    startInfo.Arguments <- "www.northwindtraders.com"

    Process.Start startInfo |> ignore

// Get the path that stores favorite links.
let myFavoritesPath = Environment.GetFolderPath Environment.SpecialFolder.Favorites

openApplication myFavoritesPath
openWithArguments ()
openWithStartInfo ()

Imports System.Diagnostics
Imports System.ComponentModel

Namespace MyProcessSample
    Class MyProcess
        ' Opens the Internet Explorer application.
        Public Sub OpenApplication(myFavoritesPath As String)
            ' Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe")

            ' Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath)
        End Sub

        ' Opens URLs and .html documents using Internet Explorer.
        Sub OpenWithArguments()
            ' URLs are not considered documents. They can only be opened
            ' by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com")

            ' Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\myPath\myFile.htm")
            Process.Start("IExplore.exe", "C:\myPath\myFile.asp")
        End Sub

        ' Uses the ProcessStartInfo class to start new processes,
        ' both in a minimized mode.
        Sub OpenWithStartInfo()
            Dim startInfo As New ProcessStartInfo("IExplore.exe")
            startInfo.WindowStyle = ProcessWindowStyle.Minimized

            Process.Start(startInfo)

            startInfo.Arguments = "www.northwindtraders.com"

            Process.Start(startInfo)
        End Sub

        Shared Sub Main()
            ' Get the path that stores favorite links.
            Dim myFavoritesPath As String = Environment.GetFolderPath(Environment.SpecialFolder.Favorites)

            Dim myProcess As New MyProcess()

            myProcess.OpenApplication(myFavoritesPath)
            myProcess.OpenWithArguments()
            myProcess.OpenWithStartInfo()
        End Sub
    End Class
End Namespace 'MyProcessSample

Remarks

Use this overload to start a process resource by specifying its file name and command-line arguments. The overload associates the resource with a new Process object.

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Note

If the address of the executable file to start is a URL, the process is not started and null is returned.

This overload lets you start a process without first creating a new Process instance. The overload is an alternative to the explicit steps of creating a new Process instance, setting the FileName and Arguments members of the StartInfo property, and calling Start for the Process instance.

Starting a process by specifying its file name and arguments is similar to typing the file name and command-line arguments in the Run dialog box of the Windows Start menu. Therefore, the file name does not need to represent an executable file. It can be of any file type for which the extension has been associated with an application installed on the system. For example the file name can have a .txt extension if you have associated text files with an editor, such as Notepad, or it can have a .doc if you have associated .doc files with a word processing tool, such as Microsoft Word. Similarly, in the same way that the Run dialog box can accept an executable file name with or without the .exe extension, the .exe extension is optional in the fileName parameter. For example, you can set the fileName parameter to either "Notepad.exe" or "Notepad". If the fileName parameter represents an executable file, the arguments parameter might represent a file to act upon, such as the text file in Notepad.exe myfile.txt. If the fileName parameter represents a command (.cmd) file, the arguments parameter must include either a "/c" or "/k" argument to specify whether the command window exits or remains after completion.

Unlike the other overloads, the overload of Start that has no parameters is not a static member. Use that overload when you have already created a Process instance and specified start information (including the file name), and you want to start a process resource and associate it with the existing Process instance. Use one of the static overloads when you want to create a new Process component rather than start a process for an existing component. Both this overload and the overload that has no parameters allow you to specify the file name of the process resource to start and command-line arguments to pass.

If you have a path variable declared in your system using quotes, you must fully qualify that path when starting any process found in that location. Otherwise, the system will not find the path. For example, if c:\mypath is not in your path, and you add it using quotation marks: path = %path%;"c:\mypath", you must fully qualify any process in c:\mypath when starting it.

Note

ASP.NET Web page and server control code executes in the context of the ASP.NET worker process on the Web server. If you use the Start method in an ASP.NET Web page or server control, the new process executes on the Web server with restricted permissions. The process does not start in the same context as the client browser, and does not have access to the user desktop.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

A note about apartment states in managed threads is necessary here. When UseShellExecute is true on the process component's StartInfo property, make sure you have set a threading model on your application by setting the attribute [STAThread] on the main() method. Otherwise, a managed thread can be in an unknown state or put in the MTA state, the latter of which conflicts with UseShellExecute being true. Some methods require that the apartment state not be unknown. If the state is not explicitly set, when the application encounters such a method, it defaults to MTA, and once set, the apartment state cannot be changed. However, MTA causes an exception to be thrown when the operating system shell is managing the thread.

See also

Applies to

Start(String)

Source:
Process.cs
Source:
Process.cs
Source:
Process.cs

Starts a process resource by specifying the name of a document or application file and associates the resource with a new Process component.

public:
 static System::Diagnostics::Process ^ Start(System::String ^ fileName);
public static System.Diagnostics.Process Start (string fileName);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static System.Diagnostics.Process Start (string fileName);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
[System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
public static System.Diagnostics.Process Start (string fileName);
static member Start : string -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
static member Start : string -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
[<System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")>]
static member Start : string -> System.Diagnostics.Process
Public Shared Function Start (fileName As String) As Process

Parameters

fileName
String

The name of a document or application file to run in the process.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that's started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Attributes
UnsupportedOSPlatformAttribute SupportedOSPlatformAttribute

Exceptions

Win32Exception

An error occurred when opening the associated file.

-or-

The file specified in the fileName could not be found.

ObjectDisposedException

The process object has already been disposed.

FileNotFoundException

The PATH environment variable has a string containing quotes.

Examples

The following example first spawns an instance of Internet Explorer and displays the contents of the Favorites folder in the browser. It then starts some other instances of Internet Explorer and displays some specific pages or sites. Finally it starts Internet Explorer with the window being minimized while navigating to a specific site.

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;
using namespace System::ComponentModel;

// Opens the Internet Explorer application.
void OpenApplication(String^ myFavoritesPath)
{
    // Start Internet Explorer. Defaults to the home page.
    Process::Start("IExplore.exe");

    // Display the contents of the favorites folder in the browser.
    Process::Start(myFavoritesPath);
}

// Opens urls and .html documents using Internet Explorer.
void OpenWithArguments()
{
    // URLs are not considered documents. They can only be opened
    // by passing them as arguments.
    Process::Start("IExplore.exe", "www.northwindtraders.com");

    // Start a Web page using a browser associated with .html and .asp files.
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.htm");
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.asp");
}

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
void OpenWithStartInfo()
{
    ProcessStartInfo^ startInfo = gcnew ProcessStartInfo("IExplore.exe");
    startInfo->WindowStyle = ProcessWindowStyle::Minimized;
    Process::Start(startInfo);
    startInfo->Arguments = "www.northwindtraders.com";
    Process::Start(startInfo);
}

int main()
{
    // Get the path that stores favorite links.
    String^ myFavoritesPath = Environment::GetFolderPath(Environment::SpecialFolder::Favorites);
    OpenApplication(myFavoritesPath);
    OpenWithArguments();
    OpenWithStartInfo();
}

using System;
using System.Diagnostics;
using System.ComponentModel;

namespace MyProcessSample
{
    class MyProcess
    {
        // Opens the Internet Explorer application.
        void OpenApplication(string myFavoritesPath)
        {
            // Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe");

            // Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath);
        }

        // Opens urls and .html documents using Internet Explorer.
        void OpenWithArguments()
        {
            // url's are not considered documents. They can only be opened
            // by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com");

            // Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.htm");
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.asp");
        }

        // Uses the ProcessStartInfo class to start new processes,
        // both in a minimized mode.
        void OpenWithStartInfo()
        {
            ProcessStartInfo startInfo = new ProcessStartInfo("IExplore.exe");
            startInfo.WindowStyle = ProcessWindowStyle.Minimized;

            Process.Start(startInfo);

            startInfo.Arguments = "www.northwindtraders.com";

            Process.Start(startInfo);
        }

        static void Main()
        {
            // Get the path that stores favorite links.
            string myFavoritesPath =
                Environment.GetFolderPath(Environment.SpecialFolder.Favorites);

            MyProcess myProcess = new MyProcess();

            myProcess.OpenApplication(myFavoritesPath);
            myProcess.OpenWithArguments();
            myProcess.OpenWithStartInfo();
        }
    }
}

module processstartstatic

open System
open System.Diagnostics

// Opens the Internet Explorer application.
let openApplication (myFavoritesPath: string) =
    // Start Internet Explorer. Defaults to the home page.
    Process.Start "IExplore.exe" |> ignore

    // Display the contents of the favorites folder in the browser.
    Process.Start myFavoritesPath |> ignore

// Opens urls and .html documents using Internet Explorer.
let openWithArguments () =
    // url's are not considered documents. They can only be opened
    // by passing them as arguments.
    Process.Start("IExplore.exe", "www.northwindtraders.com") |> ignore

    // Start a Web page using a browser associated with .html and .asp files.
    Process.Start("IExplore.exe", @"C:\myPath\myFile.htm") |> ignore
    Process.Start("IExplore.exe", @"C:\myPath\myFile.asp") |> ignore

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
let openWithStartInfo () =
    let startInfo = ProcessStartInfo "IExplore.exe"
    startInfo.WindowStyle <- ProcessWindowStyle.Minimized

    Process.Start startInfo |> ignore

    startInfo.Arguments <- "www.northwindtraders.com"

    Process.Start startInfo |> ignore

// Get the path that stores favorite links.
let myFavoritesPath = Environment.GetFolderPath Environment.SpecialFolder.Favorites

openApplication myFavoritesPath
openWithArguments ()
openWithStartInfo ()

Imports System.Diagnostics
Imports System.ComponentModel

Namespace MyProcessSample
    Class MyProcess
        ' Opens the Internet Explorer application.
        Public Sub OpenApplication(myFavoritesPath As String)
            ' Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe")

            ' Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath)
        End Sub

        ' Opens URLs and .html documents using Internet Explorer.
        Sub OpenWithArguments()
            ' URLs are not considered documents. They can only be opened
            ' by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com")

            ' Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\myPath\myFile.htm")
            Process.Start("IExplore.exe", "C:\myPath\myFile.asp")
        End Sub

        ' Uses the ProcessStartInfo class to start new processes,
        ' both in a minimized mode.
        Sub OpenWithStartInfo()
            Dim startInfo As New ProcessStartInfo("IExplore.exe")
            startInfo.WindowStyle = ProcessWindowStyle.Minimized

            Process.Start(startInfo)

            startInfo.Arguments = "www.northwindtraders.com"

            Process.Start(startInfo)
        End Sub

        Shared Sub Main()
            ' Get the path that stores favorite links.
            Dim myFavoritesPath As String = Environment.GetFolderPath(Environment.SpecialFolder.Favorites)

            Dim myProcess As New MyProcess()

            myProcess.OpenApplication(myFavoritesPath)
            myProcess.OpenWithArguments()
            myProcess.OpenWithStartInfo()
        End Sub
    End Class
End Namespace 'MyProcessSample

Remarks

Use this overload to start a process resource by specifying its file name. The overload associates the resource with a new Process object.

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Note

If the address of the executable file to start is a URL, the process is not started and null is returned.

This overload lets you start a process without first creating a new Process instance. The overload is an alternative to the explicit steps of creating a new Process instance, setting the FileName member of the StartInfo property, and calling Start for the Process instance.

You can start a ClickOnce application by setting the fileName parameter to the location (for example, a Web address) from which you originally installed the application. Do not start a ClickOnce application by specifying its installed location on your hard drive.

Starting a process by specifying its file name is similar to typing the information in the Run dialog box of the Windows Start menu. Therefore, the file name does not need to represent an executable file. It can be of any file type for which the extension has been associated with an application installed on the system. For example the file name can have a .txt extension if you have associated text files with an editor, such as Notepad, or it can have a .doc if you have associated .doc files with a word processing tool, such as Microsoft Word. Similarly, in the same way that the Run dialog box can accept an executable file name with or without the .exe extension, the .exe extension is optional in the fileName parameter. For example, you can set the fileName parameter to either "Notepad.exe" or "Notepad".

This overload does not allow command-line arguments for the process. If you need to specify one or more command-line arguments for the process, use the Process.Start(ProcessStartInfo) or Process.Start(String, String) overloads.

Unlike the other overloads, the overload of Start that has no parameters is not a static member. Use that overload when you have already created a Process instance and specified start information (including the file name), and you want to start a process resource and associate it with the existing Process instance. Use one of the static overloads when you want to create a new Process component rather than start a process for an existing component. Both this overload and the overload that has no parameters allow you to specify the file name of the process resource to start.

If you have a path variable declared in your system using quotes, you must fully qualify that path when starting any process found in that location. Otherwise, the system will not find the path. For example, if c:\mypath is not in your path, and you add it using quotation marks: path = %path%;"c:\mypath", you must fully qualify any process in c:\mypath when starting it.

Note

ASP.NET Web page and server control code executes in the context of the ASP.NET worker process on the Web server. If you use the Start method in an ASP.NET Web page or server control, the new process executes on the Web server with restricted permissions. The process does not start in the same context as the client browser, and does not have access to the user desktop.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

A note about apartment states in managed threads is necessary here. When UseShellExecute is true on the process component's StartInfo property, make sure you have set a threading model on your application by setting the attribute [STAThread] on the main() method. Otherwise, a managed thread can be in an unknown state or put in the MTA state, the latter of which conflicts with UseShellExecute being true. Some methods require that the apartment state not be unknown. If the state is not explicitly set, when the application encounters such a method, it defaults to MTA, and once set, the apartment state cannot be changed. However, MTA causes an exception to be thrown when the operating system shell is managing the thread.

See also

Applies to

Start(ProcessStartInfo)

Source:
Process.cs
Source:
Process.cs
Source:
Process.cs

Starts the process resource that is specified by the parameter containing process start information (for example, the file name of the process to start) and associates the resource with a new Process component.

public:
 static System::Diagnostics::Process ^ Start(System::Diagnostics::ProcessStartInfo ^ startInfo);
public static System.Diagnostics.Process? Start (System.Diagnostics.ProcessStartInfo startInfo);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static System.Diagnostics.Process? Start (System.Diagnostics.ProcessStartInfo startInfo);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
[System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
public static System.Diagnostics.Process? Start (System.Diagnostics.ProcessStartInfo startInfo);
public static System.Diagnostics.Process Start (System.Diagnostics.ProcessStartInfo startInfo);
static member Start : System.Diagnostics.ProcessStartInfo -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
static member Start : System.Diagnostics.ProcessStartInfo -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
[<System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")>]
static member Start : System.Diagnostics.ProcessStartInfo -> System.Diagnostics.Process
Public Shared Function Start (startInfo As ProcessStartInfo) As Process

Parameters

startInfo
ProcessStartInfo

The ProcessStartInfo that contains the information that is used to start the process, including the file name and any command-line arguments.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that's started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Attributes
UnsupportedOSPlatformAttribute SupportedOSPlatformAttribute

Exceptions

InvalidOperationException

No file name was specified in the startInfo parameter's FileName property.

-or-

The UseShellExecute property of the startInfo parameter is true and the RedirectStandardInput, RedirectStandardOutput, or RedirectStandardError property is also true.

-or-

The UseShellExecute property of the startInfo parameter is true and the UserName property is not null or empty or the Password property is not null.

ArgumentNullException

The startInfo parameter is null.

ObjectDisposedException

The process object has already been disposed.

Win32Exception

An error occurred when opening the associated file.

-or-

The file specified in the startInfo parameter's FileName property could not be found.

-or-

The sum of the length of the arguments and the length of the full path to the process exceeds 2080. The error message associated with this exception can be one of the following: "The data area passed to a system call is too small." or "Access is denied."

PlatformNotSupportedException

Method not supported on operating systems without shell support such as Nano Server (.NET Core only).

Examples

The following example first spawns an instance of Internet Explorer and displays the contents of the Favorites folder in the browser. It then starts some other instances of Internet Explorer and displays some specific pages or sites. Finally it starts Internet Explorer with the window being minimized while navigating to a specific site.

For additional examples of other uses of this method, refer to the individual properties of the ProcessStartInfo class.

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;
using namespace System::ComponentModel;

// Opens the Internet Explorer application.
void OpenApplication(String^ myFavoritesPath)
{
    // Start Internet Explorer. Defaults to the home page.
    Process::Start("IExplore.exe");

    // Display the contents of the favorites folder in the browser.
    Process::Start(myFavoritesPath);
}

// Opens urls and .html documents using Internet Explorer.
void OpenWithArguments()
{
    // URLs are not considered documents. They can only be opened
    // by passing them as arguments.
    Process::Start("IExplore.exe", "www.northwindtraders.com");

    // Start a Web page using a browser associated with .html and .asp files.
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.htm");
    Process::Start("IExplore.exe", "C:\\myPath\\myFile.asp");
}

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
void OpenWithStartInfo()
{
    ProcessStartInfo^ startInfo = gcnew ProcessStartInfo("IExplore.exe");
    startInfo->WindowStyle = ProcessWindowStyle::Minimized;
    Process::Start(startInfo);
    startInfo->Arguments = "www.northwindtraders.com";
    Process::Start(startInfo);
}

int main()
{
    // Get the path that stores favorite links.
    String^ myFavoritesPath = Environment::GetFolderPath(Environment::SpecialFolder::Favorites);
    OpenApplication(myFavoritesPath);
    OpenWithArguments();
    OpenWithStartInfo();
}

using System;
using System.Diagnostics;
using System.ComponentModel;

namespace MyProcessSample
{
    class MyProcess
    {
        // Opens the Internet Explorer application.
        void OpenApplication(string myFavoritesPath)
        {
            // Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe");

            // Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath);
        }

        // Opens urls and .html documents using Internet Explorer.
        void OpenWithArguments()
        {
            // url's are not considered documents. They can only be opened
            // by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com");

            // Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.htm");
            Process.Start("IExplore.exe", "C:\\myPath\\myFile.asp");
        }

        // Uses the ProcessStartInfo class to start new processes,
        // both in a minimized mode.
        void OpenWithStartInfo()
        {
            ProcessStartInfo startInfo = new ProcessStartInfo("IExplore.exe");
            startInfo.WindowStyle = ProcessWindowStyle.Minimized;

            Process.Start(startInfo);

            startInfo.Arguments = "www.northwindtraders.com";

            Process.Start(startInfo);
        }

        static void Main()
        {
            // Get the path that stores favorite links.
            string myFavoritesPath =
                Environment.GetFolderPath(Environment.SpecialFolder.Favorites);

            MyProcess myProcess = new MyProcess();

            myProcess.OpenApplication(myFavoritesPath);
            myProcess.OpenWithArguments();
            myProcess.OpenWithStartInfo();
        }
    }
}

module processstartstatic

open System
open System.Diagnostics

// Opens the Internet Explorer application.
let openApplication (myFavoritesPath: string) =
    // Start Internet Explorer. Defaults to the home page.
    Process.Start "IExplore.exe" |> ignore

    // Display the contents of the favorites folder in the browser.
    Process.Start myFavoritesPath |> ignore

// Opens urls and .html documents using Internet Explorer.
let openWithArguments () =
    // url's are not considered documents. They can only be opened
    // by passing them as arguments.
    Process.Start("IExplore.exe", "www.northwindtraders.com") |> ignore

    // Start a Web page using a browser associated with .html and .asp files.
    Process.Start("IExplore.exe", @"C:\myPath\myFile.htm") |> ignore
    Process.Start("IExplore.exe", @"C:\myPath\myFile.asp") |> ignore

// Uses the ProcessStartInfo class to start new processes,
// both in a minimized mode.
let openWithStartInfo () =
    let startInfo = ProcessStartInfo "IExplore.exe"
    startInfo.WindowStyle <- ProcessWindowStyle.Minimized

    Process.Start startInfo |> ignore

    startInfo.Arguments <- "www.northwindtraders.com"

    Process.Start startInfo |> ignore

// Get the path that stores favorite links.
let myFavoritesPath = Environment.GetFolderPath Environment.SpecialFolder.Favorites

openApplication myFavoritesPath
openWithArguments ()
openWithStartInfo ()

Imports System.Diagnostics
Imports System.ComponentModel

Namespace MyProcessSample
    Class MyProcess
        ' Opens the Internet Explorer application.
        Public Sub OpenApplication(myFavoritesPath As String)
            ' Start Internet Explorer. Defaults to the home page.
            Process.Start("IExplore.exe")

            ' Display the contents of the favorites folder in the browser.
            Process.Start(myFavoritesPath)
        End Sub

        ' Opens URLs and .html documents using Internet Explorer.
        Sub OpenWithArguments()
            ' URLs are not considered documents. They can only be opened
            ' by passing them as arguments.
            Process.Start("IExplore.exe", "www.northwindtraders.com")

            ' Start a Web page using a browser associated with .html and .asp files.
            Process.Start("IExplore.exe", "C:\myPath\myFile.htm")
            Process.Start("IExplore.exe", "C:\myPath\myFile.asp")
        End Sub

        ' Uses the ProcessStartInfo class to start new processes,
        ' both in a minimized mode.
        Sub OpenWithStartInfo()
            Dim startInfo As New ProcessStartInfo("IExplore.exe")
            startInfo.WindowStyle = ProcessWindowStyle.Minimized

            Process.Start(startInfo)

            startInfo.Arguments = "www.northwindtraders.com"

            Process.Start(startInfo)
        End Sub

        Shared Sub Main()
            ' Get the path that stores favorite links.
            Dim myFavoritesPath As String = Environment.GetFolderPath(Environment.SpecialFolder.Favorites)

            Dim myProcess As New MyProcess()

            myProcess.OpenApplication(myFavoritesPath)
            myProcess.OpenWithArguments()
            myProcess.OpenWithStartInfo()
        End Sub
    End Class
End Namespace 'MyProcessSample

Remarks

Use this overload to start a process resource by specifying a ProcessStartInfo instance. The overload associates the resource with a new Process object.

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Note

If the address of the executable file to start is a URL, the process is not started and null is returned.

This overload lets you start a process without first creating a new Process instance. Using this overload with a ProcessStartInfo parameter is an alternative to the explicit steps of creating a new Process instance, setting its StartInfo properties, and calling Start for the Process instance.

Using a ProcessStartInfo instance as the parameter lets you call Start with the most control over what is passed into the call to start the process. If you need to pass only a file name or a file name and arguments, it is not necessary to create a new ProcessStartInfo instance, although that is an option. The only Process.StartInfo property that must be set is the FileName property. The FileName property does not need to represent an executable file. It can be of any file type for which the extension has been associated with an application that is installed on the system. For example, the FileName property can have a .txt extension if you have associated text files with an editor, such as Notepad, or it can have a .doc extension if you have associated .doc files with a word processing tool, such as Microsoft Word.

You can start a ClickOnce application by specifying the location (for example, a Web address) from which you originally installed the application. Do not start a ClickOnce application by specifying its installed location on your hard drive.

If the ProcessStartInfo.UserName and ProcessStartInfo.Password properties of the StartInfo instance are set, the unmanaged CreateProcessWithLogonW function is called, which starts the process in a new window even if the ProcessStartInfo.CreateNoWindow property value is true or the ProcessStartInfo.WindowStyle property value is ProcessWindowStyle.Hidden. If the ProcessStartInfo.Domain property is null, the ProcessStartInfo.UserName property must be in UPN format, user@DNS_domain_name.

Unlike the other overloads, the overload of Start that has no parameters is not a static member. Use that overload when you have already created a Process instance and specified start information (including the file name), and you want to start a process resource and associate it with the existing Process instance. Use one of the static overloads when you want to create a new Process component rather than start a process for an existing component. Both this overload and the overload that has no parameters allow you to specify the start information for the process resource by using a ProcessStartInfo instance.

If you have a path variable declared in your system using quotes, you must fully qualify that path when starting any process found in that location. Otherwise, the system will not find the path. For example, if c:\mypath is not in your path, and you add it using quotation marks: path = %path%;"c:\mypath", you must fully qualify any process in c:\mypath when starting it.

Note

ASP.NET Web page and server control code executes in the context of the ASP.NET worker process on the Web server. If you use the Start method in an ASP.NET Web page or server control, the new process executes on the Web server with restricted permissions. The process does not start in the same context as the client browser, and does not have access to the user desktop.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

A note about apartment states in managed threads is necessary here. When UseShellExecute is true on the startInfo parameter, make sure you have set a threading model on your application by setting the attribute [STAThread] on the main() method. Otherwise, a managed thread can be in an unknown state or put in the MTA state, the latter of which conflicts with UseShellExecute being true. Some methods require that the apartment state not be unknown. If the state is not explicitly set, when the application encounters such a method, it defaults to MTA, and once set, the apartment state cannot be changed. However, MTA causes an exception to be thrown when the operating system shell is managing the thread.

See also

Applies to

Start()

Source:
Process.cs
Source:
Process.cs
Source:
Process.cs

Starts (or reuses) the process resource that is specified by the StartInfo property of this Process component and associates it with the component.

public:
 bool Start();
public bool Start ();
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public bool Start ();
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
[System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
public bool Start ();
member this.Start : unit -> bool
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
member this.Start : unit -> bool
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
[<System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")>]
member this.Start : unit -> bool
Public Function Start () As Boolean

Returns

Boolean

true if a process resource is started; false if no new process resource is started (for example, if an existing process is reused).

Attributes
UnsupportedOSPlatformAttribute SupportedOSPlatformAttribute

Exceptions

InvalidOperationException

No file name was specified in the Process component's StartInfo.

-or-

The UseShellExecute member of the StartInfo property is true while RedirectStandardInput, RedirectStandardOutput, or RedirectStandardError is true.

Win32Exception

There was an error in opening the associated file.

ObjectDisposedException

The process object has already been disposed.

PlatformNotSupportedException

Method not supported on operating systems without shell support such as Nano Server (.NET Core only).

Examples

The following example uses an instance of the Process class to start a process.

#using <System.dll>
using namespace System;
using namespace System::Diagnostics;
using namespace System::ComponentModel;

int main()
{
    Process^ myProcess = gcnew Process;

    try
    {
        myProcess->StartInfo->UseShellExecute = false;
        // You can start any process, HelloWorld is a do-nothing example.
        myProcess->StartInfo->FileName = "C:\\HelloWorld.exe";
        myProcess->StartInfo->CreateNoWindow = true;
        myProcess->Start();
        // This code assumes the process you are starting will terminate itself. 
        // Given that it is started without a window so you cannot terminate it 
        // on the desktop, it must terminate itself or you can do it programmatically
        // from this application using the Kill method.
    }
    catch ( Exception^ e ) 
    {
        Console::WriteLine( e->Message );
    }
}

using System;
using System.Diagnostics;
using System.ComponentModel;

namespace MyProcessSample
{
    class MyProcess
    {
        public static void Main()
        {
            try
            {
                using (Process myProcess = new Process())
                {
                    myProcess.StartInfo.UseShellExecute = false;
                    // You can start any process, HelloWorld is a do-nothing example.
                    myProcess.StartInfo.FileName = "C:\\HelloWorld.exe";
                    myProcess.StartInfo.CreateNoWindow = true;
                    myProcess.Start();
                    // This code assumes the process you are starting will terminate itself.
                    // Given that it is started without a window so you cannot terminate it
                    // on the desktop, it must terminate itself or you can do it programmatically
                    // from this application using the Kill method.
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

open System.Diagnostics

try
    use myProcess = new Process()
    myProcess.StartInfo.UseShellExecute <- false
    // You can start any process, HelloWorld is a do-nothing example.
    myProcess.StartInfo.FileName <- @"C:\HelloWorld.exe"
    myProcess.StartInfo.CreateNoWindow <- true
    myProcess.Start() |> ignore
// This code assumes the process you are starting will terminate itself.
// Given that it is started without a window so you cannot terminate it
// on the desktop, it must terminate itself or you can do it programmatically
// from this application using the Kill method.
with e ->
    printfn $"{e.Message}"

Imports System.Diagnostics
Imports System.ComponentModel

Namespace MyProcessSample
    Class MyProcess
        Public Shared Sub Main()
            Try
                Using myProcess As New Process()

                    myProcess.StartInfo.UseShellExecute = False
                    ' You can start any process, HelloWorld is a do-nothing example.
                    myProcess.StartInfo.FileName = "C:\\HelloWorld.exe"
                    myProcess.StartInfo.CreateNoWindow = True
                    myProcess.Start()
                    ' This code assumes the process you are starting will terminate itself. 
                    ' Given that it is started without a window so you cannot terminate it 
                    ' on the desktop, it must terminate itself or you can do it programmatically
                    ' from this application using the Kill method.
                End Using
            Catch e As Exception
                Console.WriteLine((e.Message))
            End Try
        End Sub
    End Class
End Namespace

Remarks

Use this overload to start a process resource and associate it with the current Process component. The return value true indicates that a new process resource was started. If the process resource specified by the FileName member of the StartInfo property is already running on the computer, no additional process resource is started. Instead, the running process resource is reused and false is returned.

You can start a ClickOnce application by specifying the location (for example, a Web address) from which you originally installed the application. Do not start a ClickOnce application by specifying its installed location on your hard drive.

Important

Using an instance of this object with untrusted data is a security risk. Use this object only with trusted data. For more information, see Validate All Inputs.

Note

If you are using Visual Studio, this overload of the Start method is the one that you insert into your code after you drag a Process component onto the designer. Use the Properties window to expand the StartInfo category and write the appropriate value into the FileName property. Your changes will appear in the form's InitializeComponent procedure.

This overload of Start is not a static method. You must call it from an instance of the Process class. Before calling Start, you must first specify StartInfo property information for this Process instance, because that information is used to determine the process resource to start.

The other overloads of the Start method are static members. You do not need to create an instance of the Process component before you call those overloads of the method. Instead, you can call Start for the Process class itself, and a new Process component is created if the process was started. Or, null is returned if a process was reused. The process resource is automatically associated with the new Process component that is returned by the Start method.

The StartInfo members can be used to duplicate the functionality of the Run dialog box of the Windows Start menu. Anything that can be typed into a command line can be started by setting the appropriate values in the StartInfo property. The only StartInfo property that must be set is the FileName property. The FileName property does not have to be an executable file. It can be of any file type for which the extension has been associated with an application that is installed on the system. For example, the FileName property can have a .txt extension if you have associated text files with an editor, such as Notepad, or it can have a .doc extension if you have associated .doc files with a word processing tool, such as Microsoft Word.

In the command line, you can specify actions to take for certain types of files. For example, you can print documents or edit text files. Specify these actions using the Verb member of the StartInfo property. For other types of files, you can specify command-line arguments when you start the file from the Run dialog box. For example, you can pass a URL as an argument if you specify your browser as the FileName. These arguments can be specified in the StartInfo property's Arguments member.

If you have a path variable declared in your system using quotes, you must fully qualify that path when starting any process found in that location. Otherwise, the system will not find the path. For example, if c:\mypath is not in your path, and you add it using quotation marks: path = %path%;"c:\mypath", you must fully qualify any process in c:\mypath when starting it.

Note

ASP.NET Web page and server control code executes in the context of the ASP.NET worker process on the Web server. If you use the Start method in an ASP.NET Web page or server control, the new process executes on the Web server with restricted permissions. The process does not start in the same context as the client browser, and does not have access to the user desktop.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property.

A note about apartment states in managed threads is necessary here. When UseShellExecute is true on the process component's StartInfo property, make sure you have set a threading model on your application by setting the attribute [STAThread] on the main() method. Otherwise, a managed thread can be in an unknown state or put in the MTA state, the latter of which conflicts with UseShellExecute being true. Some methods require that the apartment state not be unknown. If the state is not explicitly set, when the application encounters such a method, it defaults to MTA, and once set, the apartment state cannot be changed. However, MTA causes an exception to be thrown when the operating system shell is managing the thread.

See also

Applies to

Start(String, IEnumerable<String>)

Source:
Process.cs
Source:
Process.cs
Source:
Process.cs

Starts a process resource by specifying the name of an application and a set of command line arguments.

public:
 static System::Diagnostics::Process ^ Start(System::String ^ fileName, System::Collections::Generic::IEnumerable<System::String ^> ^ arguments);
public static System.Diagnostics.Process Start (string fileName, System.Collections.Generic.IEnumerable<string> arguments);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static System.Diagnostics.Process Start (string fileName, System.Collections.Generic.IEnumerable<string> arguments);
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
[System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
public static System.Diagnostics.Process Start (string fileName, System.Collections.Generic.IEnumerable<string> arguments);
static member Start : string * seq<string> -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
static member Start : string * seq<string> -> System.Diagnostics.Process
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
[<System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")>]
static member Start : string * seq<string> -> System.Diagnostics.Process
Public Shared Function Start (fileName As String, arguments As IEnumerable(Of String)) As Process

Parameters

fileName
String

The name of a document or application file to run in the process.

arguments
IEnumerable<String>

The command-line arguments to pass when starting the process.

Returns

Process

A new Process that is associated with the process resource, or null if no process resource is started.

Attributes
UnsupportedOSPlatformAttribute SupportedOSPlatformAttribute

Remarks

Each argument will be escaped automatically if required.

Important

Calling this method with untrusted data is a security risk. Call this method only with trusted data. For more information, see Validate All Inputs.

Applies to