Environment.GetEnvironmentVariable 方法

参考

定义

命名空间:: System

程序集:: System.Runtime.Extensions.dll

程序集:: System.Runtime.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

检索环境变量的值。

重载

GetEnvironmentVariable(String)	从当前进程检索环境变量的值。
GetEnvironmentVariable(String, EnvironmentVariableTarget)	从当前进程或者从当前用户或本地计算机的 Windows 操作系统注册表项检索环境变量的值。

GetEnvironmentVariable(String)

Source:: Environment.cs

Source:: Environment.cs

Source:: Environment.cs

从当前进程检索环境变量的值。

public:
 static System::String ^ GetEnvironmentVariable(System::String ^ variable);

public static string GetEnvironmentVariable (string variable);

public static string? GetEnvironmentVariable (string variable);

static member GetEnvironmentVariable : string -> string

Public Shared Function GetEnvironmentVariable (variable As String) As String

参数

variable: String

环境变量的名称。

String

variable 指定的环境变量的值；或者如果找不到环境变量，则返回 null。

例外

ArgumentNullException

variable 为 null。

SecurityException

调用方没有执行此操作所需的权限。

示例

下面的示例使用 GetEnvironmentVariable 方法检索 windir 环境变量，其中包含 Windows 目录的路径。

using namespace System;
using namespace System::IO;

void main()
{
      if (Environment::OSVersion->Platform == PlatformID::Win32NT)
      {
            // Change the directory to %WINDIR%
            Environment::CurrentDirectory = Environment::GetEnvironmentVariable( "windir" );
            DirectoryInfo^ info = gcnew DirectoryInfo( "." );

            Console::WriteLine("Directory Info:   {0}", info->FullName);
      }
      else
      {
            Console::WriteLine("This example runs on Windows only.");
      }
}
// The example displays output like the following on a .NET implementation running on Windows:
//        Directory Info:   C:\windows
// The example displays the following output on a .NET implementation on Unix-based systems:
//        This example runs on Windows only.

using System;
using System.IO;

public class Example
{
   public static void Main()
   {
      if (Environment.OSVersion.Platform == PlatformID.Win32NT)
      {
         // Change the directory to %WINDIR%
         Environment.CurrentDirectory = Environment.GetEnvironmentVariable("windir");
         DirectoryInfo info = new DirectoryInfo(".");

         Console.WriteLine("Directory Info:   " + info.FullName);
      }
      else
      {
         Console.WriteLine("This example runs on Windows only.");
      }
   }
}
// The example displays output like the following on a .NET implementation running on Windows:
//        Directory Info:   C:\windows
// The example displays the following output on a .NET implementation on Unix-based systems:
//        This example runs on Windows only.

open System
open System.IO

if Environment.OSVersion.Platform = PlatformID.Win32NT then
    // Change the directory to %WINDIR%
    Environment.CurrentDirectory <- Environment.GetEnvironmentVariable "windir"
    
    let info = DirectoryInfo "."

    printfn $"Directory Info:   {info.FullName}"
else
    printfn "This example runs on Windows only."
// The example displays output like the following on a .NET implementation running on Windows:
//        Directory Info:   C:\windows
// The example displays the following output on a .NET implementation on Unix-based systems:
//        This example runs on Windows only.

Imports System.IO

Module Example
   Public Sub Main()
        If Environment.OSVersion.Platform = PlatformID.Win32NT Then
            ' Change the directory to %WINDIR%
            Environment.CurrentDirectory = Environment.GetEnvironmentVariable("windir")
            Dim info As New DirectoryInfo(".")
            Console.WriteLine("Directory Info:   " + info.FullName)
         Else
            Console.WriteLine("This example runs on Windows only.")
         End If
   End Sub
End Module
' The example displays output like the following on a .NET implementation running on Windows:
'        Directory Info:   C:\windows
' The example displays the following output on a .NET implementation on Unix-based systems:
'        This example runs on Windows only.

以下示例尝试从进程环境块检索名为 Test1 的环境变量的值。如果变量不存在，示例将创建它并检索其值。该示例显示变量的值。如果示例创建了变量，则它还使用枚举的每个成员EnvironmentVariableTarget调用 GetEnvironmentVariables(EnvironmentVariableTarget) 方法，以确定只能从当前进程环境块检索该变量。最后，如果示例创建了变量，则会将其删除。

using System;

public class Example
{
   public static void Main()
   {
      string value;
      bool toDelete = false;

      // Check whether the environment variable exists.
      value = Environment.GetEnvironmentVariable("Test1");
      // If necessary, create it.
      if (value == null)
      {
         Environment.SetEnvironmentVariable("Test1", "Value1");
         toDelete = true;

         // Now retrieve it.
         value = Environment.GetEnvironmentVariable("Test1");
      }
      // Display the value.
      Console.WriteLine($"Test1: {value}\n");

      // Confirm that the value can only be retrieved from the process
      // environment block if running on a Windows system.
      if (Environment.OSVersion.Platform == PlatformID.Win32NT)
      {
         Console.WriteLine("Attempting to retrieve Test1 from:");
         foreach (EnvironmentVariableTarget enumValue in
                           Enum.GetValues(typeof(EnvironmentVariableTarget))) {
            value = Environment.GetEnvironmentVariable("Test1", enumValue);
            Console.WriteLine($"   {enumValue}: {(value != null ? "found" : "not found")}");
         }
         Console.WriteLine();
      }

      // If we've created it, now delete it.
      if (toDelete) {
         Environment.SetEnvironmentVariable("Test1", null);
         // Confirm the deletion.
         if (Environment.GetEnvironmentVariable("Test1") == null)
            Console.WriteLine("Test1 has been deleted.");
      }
   }
}
// The example displays the following output if run on a Windows system:
//      Test1: Value1
//
//      Attempting to retrieve Test1 from:
//         Process: found
//         User: not found
//         Machine: not found
//
//      Test1 has been deleted.
//
// The example displays the following output if run on a Unix-based system:
//      Test1: Value1
//
//      Test1 has been deleted.

module Example

open System

let mutable toDelete = false

// Check whether the environment variable exists.
let value = 
    let v = Environment.GetEnvironmentVariable "Test1"
    // If necessary, create it.
    if isNull v then
        Environment.SetEnvironmentVariable("Test1", "Value1")
        toDelete <- true
        Environment.GetEnvironmentVariable "Test1"
    else 
        v

// Display the value.
printfn $"Test1: {value}\n"

// Confirm that the value can only be retrieved from the process
// environment block if running on a Windows system.
if Environment.OSVersion.Platform = PlatformID.Win32NT then
    printfn "Attempting to retrieve Test1 from:"
    for enumValue in Enum.GetValues typeof<EnvironmentVariableTarget> do
        let value = Environment.GetEnvironmentVariable("Test1", enumValue :?> EnvironmentVariableTarget)
        printfn $"""   {enumValue}: {if value <> null then "found" else "not found"}"""
    printfn ""

// If we've created it, now delete it.
if toDelete then
    Environment.SetEnvironmentVariable("Test1", null)
    // Confirm the deletion.
    if Environment.GetEnvironmentVariable "Test1" |> isNull then
        printfn "Test1 has been deleted."
// The example displays the following output if run on a Windows system:
//      Test1: Value1
//
//      Attempting to retrieve Test1 from:
//         Process: found
//         User: not found
//         Machine: not found
//
//      Test1 has been deleted.
//
// The example displays the following output if run on a Unix-based system:
//      Test1: Value1
//
//      Test1 has been deleted.

Module Example
   Public Sub Main()
      Dim value As String 
      Dim toDelete As Boolean = False
      
      ' Check whether the environment variable exists.
      value = Environment.GetEnvironmentVariable("Test1")
      ' If necessary, create it.
      If value Is Nothing Then
         Environment.SetEnvironmentVariable("Test1", "Value1")
         toDelete = True
         
         ' Now retrieve it.
         value = Environment.GetEnvironmentVariable("Test1")
      End If
      ' Display the value.
      Console.WriteLine($"Test1: {value}")
      Console.WriteLine()
      
      ' Confirm that the value can only be retrieved from the process
      ' environment block if running on a Windows system.
      If Environment.OSVersion.Platform = PlatformID.Win32NT Then
         Console.WriteLine("Attempting to retrieve Test1 from:")
         For Each enumValue As EnvironmentVariableTarget In 
                           [Enum].GetValues(GetType(EnvironmentVariableTarget))
            value = Environment.GetEnvironmentVariable("Test1", enumValue)
            Console.WriteLine($"   {enumValue}: {If(value IsNot Nothing, "found", "not found")}")
         Next
         Console.WriteLine()
      End If

      ' If we've created it, now delete it.
      If toDelete Then 
         Environment.SetEnvironmentVariable("Test1", Nothing)
         ' Confirm the deletion.
         If Environment.GetEnvironmentVariable("Test1") = Nothing Then
            Console.WriteLine("Test1 has been deleted.")
         End If
      End If         
   End Sub
End Module
' The example displays the following output if run on a Windows system:
'      Test1: Value1
'
'      Attempting to retrieve Test1 from:
'         Process: found
'         User: not found
'         Machine: not found
'
'      Test1 has been deleted.
'
' The example displays the following output if run on a Unix-based system:
'      Test1: Value1
'
'      Test1 has been deleted.

注解

有关此 API 的详细信息，请参阅 Environment.GetEnvironmentVariable 的补充 API 备注。

另请参阅

适用于

GetEnvironmentVariable(String, EnvironmentVariableTarget)

Source:: Environment.cs

Source:: Environment.cs

Source:: Environment.cs

从当前进程或者从当前用户或本地计算机的 Windows 操作系统注册表项检索环境变量的值。

public:
 static System::String ^ GetEnvironmentVariable(System::String ^ variable, EnvironmentVariableTarget target);

public static string? GetEnvironmentVariable (string variable, EnvironmentVariableTarget target);

public static string GetEnvironmentVariable (string variable, EnvironmentVariableTarget target);

static member GetEnvironmentVariable : string * EnvironmentVariableTarget -> string

Public Shared Function GetEnvironmentVariable (variable As String, target As EnvironmentVariableTarget) As String

参数

variable: String

环境变量名。

target: EnvironmentVariableTarget

EnvironmentVariableTarget 值之一。仅在 Process 运行在类似 Unix 的系统上的 .NET 上受支持。

String

variable 和 target 参数指定的环境变量的值；或者如果找不到环境变量，则返回 null。

例外

ArgumentNullException

variable 为 null。

ArgumentException

target 不是有效的 EnvironmentVariableTarget 值。

SecurityException

调用方没有执行此操作所需的权限。

示例

以下示例为 EnvironmentVariableTarget.Process、 EnvironmentVariableTarget.User和 Machine 目标创建环境变量，检查操作系统注册表是否包含用户和计算机环境变量，然后删除环境变量。由于类似 Unix 的系统上的 .NET 不支持每用户和每计算机环境变量，因此仅 SetEnvironmentVariable(String, String) 和 SetEnvironmentVariable(String, String, EnvironmentVariableTarget) 值为 EnvironmentVariableTarget.Process 成功将环境变量存储到进程环境块。

using System;
using System.Collections;
using Microsoft.Win32;

class Sample
{
    public static void Main()
    {
        // Environment variable names for default, process, user, and machine targets.
        string defaultEnvVar = nameof(defaultEnvVar);
        string processEnvVar = nameof(processEnvVar);
        string userEnvVar = nameof(userEnvVar);
        string machineEnvVar = nameof(machineEnvVar);

        string dft = nameof(dft);
        string process = nameof(process);
        string user = nameof(user);
        string machine = nameof(machine);

        // Set the environment variable for each target.
        Console.WriteLine("Setting environment variables for each target...\n");
        // The default target (the current process).
        Environment.SetEnvironmentVariable(defaultEnvVar, dft);
        // The current process.
        Environment.SetEnvironmentVariable(processEnvVar, process,
                                           EnvironmentVariableTarget.Process);
        // The current user.
        Environment.SetEnvironmentVariable(userEnvVar, user,
                                           EnvironmentVariableTarget.User);
        // The local machine.
        Environment.SetEnvironmentVariable(machineEnvVar, machine,
                                           EnvironmentVariableTarget.Machine);

        // Define an array of environment variables.
        string[] envVars = { defaultEnvVar,processEnvVar, userEnvVar, machineEnvVar };

        // Try to get the environment variables from each target.
        // The default (no specified target).
        Console.WriteLine("Retrieving environment variables from the default target:");
        foreach (var envVar in envVars)
        {
          var value = Environment.GetEnvironmentVariable(envVar) ?? "(none)";
          Console.WriteLine($"   {envVar}: {value}");
        }
        // The process block.
        Console.WriteLine("\nRetrieving environment variables from the Process target:");
        foreach (var envVar in envVars)
        {
          var value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Process) ?? "(none)";
          Console.WriteLine($"   {envVar}: {value}");
        }
        // The user block.
        Console.WriteLine("\nRetrieving environment variables from the User target:");
        foreach (var envVar in envVars)
        {
          var value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.User) ?? "(none)";
          Console.WriteLine($"   {envVar}: {value}");
        }
        // The machine block.
        Console.WriteLine("\nRetrieving environment variables from the Machine target:");
        foreach (var envVar in envVars)
        {
          var value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Machine) ?? "(none)";
          Console.WriteLine($"   {envVar}: {value}");
        }

        // Delete the environment variable for each target.
        Console.WriteLine("\nDeleting environment variables for each target...\n");
        // The default target (the current process).
        Environment.SetEnvironmentVariable(defaultEnvVar, null);
        // The current process.
        Environment.SetEnvironmentVariable(processEnvVar, null,
                                           EnvironmentVariableTarget.Process);
        // The current user.
        Environment.SetEnvironmentVariable(userEnvVar, null,
                                           EnvironmentVariableTarget.User);
        // The local machine.
        Environment.SetEnvironmentVariable(machineEnvVar, null,
                                           EnvironmentVariableTarget.Machine);
    }
}
// The example displays the following output if run on a Windows system:
//      Setting environment variables for each target...
//
//      Retrieving environment variables from the default target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Process target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the User target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Machine target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: machine
//
//      Deleting environment variables for each target...
//
// The example displays the following output if run on a Unix-based system:
//
//      Setting environment variables for each target...
//
//      Retrieving environment variables from the default target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Process target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the User target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Machine target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Deleting environment variables for each target...

module Sample

open System

// Environment variable names for default, process, user, and machine targets.
let rec defaultEnvVar = nameof defaultEnvVar
let rec processEnvVar = nameof processEnvVar
let rec userEnvVar = nameof userEnvVar
let rec machineEnvVar = nameof machineEnvVar

let rec dft = nameof dft
let rec proc = nameof proc
let rec user = nameof user
let rec machine = nameof machine

// Set the environment variable for each target.
printfn "Setting environment variables for each target...\n"
// The default target (the current process).
Environment.SetEnvironmentVariable(defaultEnvVar, dft)
// The current process.
Environment.SetEnvironmentVariable(processEnvVar, proc, EnvironmentVariableTarget.Process)
// The current user.
Environment.SetEnvironmentVariable(userEnvVar, user, EnvironmentVariableTarget.User)
// The local machine.
Environment.SetEnvironmentVariable(machineEnvVar, machine, EnvironmentVariableTarget.Machine)

// Define a list of environment variables.
let envVars = [ defaultEnvVar; processEnvVar; userEnvVar; machineEnvVar ]

// Try to get the environment variables from each target.
// The default (no specified target).
printfn "Retrieving environment variables from the default target:"
for envVar in envVars do
    let value = 
        match Environment.GetEnvironmentVariable envVar with
        | null -> "(none)"
        | v -> v
    printfn $"   {envVar}: {value}"

// The process block.
printfn "\nRetrieving environment variables from the Process target:"
for envVar in envVars do
    let value = 
        match Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Process) with
        | null -> "(none)"
        | v -> v
    printfn $"   {envVar}: {value}"

// The user block.
printfn "\nRetrieving environment variables from the User target:"
for envVar in envVars do
    let value = 
        match Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.User) with
        | null -> "(none)"
        | v -> v
    printfn $"   {envVar}: {value}"

// The machine block.
printfn "\nRetrieving environment variables from the Machine target:"
for envVar in envVars do
    let value = 
        match Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Machine) with
        | null -> "(none)"
        | v -> v
    printfn $"   {envVar}: {value}"

// Delete the environment variable for each target.
printfn "\nDeleting environment variables for each target...\n"
// The default target (the current process).
Environment.SetEnvironmentVariable(defaultEnvVar, null)
// The current process.
Environment.SetEnvironmentVariable(processEnvVar, null, EnvironmentVariableTarget.Process)
// The current user.
Environment.SetEnvironmentVariable(userEnvVar, null, EnvironmentVariableTarget.User)
// The local machine.
Environment.SetEnvironmentVariable(machineEnvVar, null, EnvironmentVariableTarget.Machine)

// The example displays the following output if run on a Windows system:
//      Setting environment variables for each target...
//
//      Retrieving environment variables from the default target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Process target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the User target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: user
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Machine target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: machine
//
//      Deleting environment variables for each target...
//
// The example displays the following output if run on a Unix-based system:
//
//      Setting environment variables for each target...
//
//      Retrieving environment variables from the default target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Process target:
//        defaultEnvVar: dft
//        processEnvVar: process
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the User target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Retrieving environment variables from the Machine target:
//        defaultEnvVar: (none)
//        processEnvVar: (none)
//        userEnvVar: (none)
//        machineEnvVar: (none)
//
//      Deleting environment variables for each target...

Imports System.Collections
Imports Microsoft.Win32

Module Sample 
    Public Sub Main() 
        ' Environment variable names for default, process, user, and machine targets.
        Dim defaultEnvVar As String = NameOf(defaultEnvVar)
        Dim processEnvVar As String = NameOf(processEnvVar)
        Dim userEnvVar As String = NameOf(userEnvVar)
        Dim machineEnvVar As String = NameOf(machineEnvVar)

        Dim dft As String = NameOf(dft)
        Dim process As String = NameOf(process)
        Dim user As String = NameOf(user)
        Dim machine As String = NameOf(machine)

        ' Set the environment variable for each target.
        Console.WriteLine("Setting environment variables for each target...")
        ' The default target (the current process).
        Environment.SetEnvironmentVariable(defaultEnvVar, dft)
        ' The current process.
        Environment.SetEnvironmentVariable(processEnvVar, process, 
                                           EnvironmentVariableTarget.Process)
        ' The current user.
        Environment.SetEnvironmentVariable(userEnvVar, user, 
                                           EnvironmentVariableTarget.User)
        ' The local machine.
        Environment.SetEnvironmentVariable(machineEnvVar, machine, 
                                           EnvironmentVariableTarget.Machine)
        Console.WriteLine()

        ' Define an array of environment variables.
        Dim envVars As String() = { defaultEnvVar, processEnvVar, userEnvVar, machineEnvVar }
        
        ' Try to get the environment variables from each target.
        ' The default (no specified target).
        Console.WriteLine("Retrieving environment variables from the default target:")
        For Each envVar in envVars
          Dim value = Environment.GetEnvironmentVariable(envVar)
          Console.WriteLine($"   {envVar}: {If(value IsNot Nothing, value, "(none)")}")
        Next
        Console.WriteLine()
        ' The process block.
        Console.WriteLine("Retrieving environment variables from the Process target:")
        For Each envVar in envVars
          Dim value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Process)
          Console.WriteLine($"   {envVar}: {If(value IsNot Nothing, value, "(none)")}")
        Next
        Console.WriteLine()
        ' The user block.
        Console.WriteLine("Retrieving environment variables from the User target:")
        For Each envVar in envVars
          Dim value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.User)
          Console.WriteLine($"   {envVar}: {value}")
        Next
        Console.WriteLine()
        ' The machine block.
        Console.WriteLine("Retrieving environment variables from the Machine target:")
        For Each envVar in envVars
          Dim value = Environment.GetEnvironmentVariable(envVar, EnvironmentVariableTarget.Machine)
          Console.WriteLine($"   {envVar}: {value}")
        Next
        Console.WriteLine()

        ' Delete the environment variable for each target.
        Console.WriteLine("Deleting environment variables for each target...")
        ' The default target (the current process).
        Environment.SetEnvironmentVariable(defaultEnvVar, Nothing)
        ' The current process.
        Environment.SetEnvironmentVariable(processEnvVar, Nothing, 
                                           EnvironmentVariableTarget.Process)
        ' The current user.
        Environment.SetEnvironmentVariable(userEnvVar, Nothing, 
                                           EnvironmentVariableTarget.User)
        ' The local machine.
        Environment.SetEnvironmentVariable(machineEnvVar, Nothing, 
                                           EnvironmentVariableTarget.Machine)
    End Sub
End Module
' The example displays the following output if run on a Windows system:
'      Setting environment variables for each target...
'
'      Retrieving environment variables from the default target:
'        defaultEnvVar: dft
'        processEnvVar: process
'        userEnvVar: user
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the Process target:
'        defaultEnvVar: dft
'        processEnvVar: process
'        userEnvVar: user
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the User target:
'        defaultEnvVar: (none)
'        processEnvVar: (none)
'        userEnvVar: user
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the Machine target:
'        defaultEnvVar: (none)
'        processEnvVar: (none)
'        userEnvVar: (none)
'        machineEnvVar: machine
'
'      Deleting environment variables for each target...
'
' The example displays the following output if run on a Unix-based system:
'
'      Setting environment variables for each target...
'
'      Retrieving environment variables from the default target:
'        defaultEnvVar: dft
'        processEnvVar: process
'        userEnvVar: (none)
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the Process target:
'        defaultEnvVar: dft
'        processEnvVar: process
'        userEnvVar: (none)
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the User target:
'        defaultEnvVar: (none)
'        processEnvVar: (none)
'        userEnvVar: (none)
'        machineEnvVar: (none)
'
'      Retrieving environment variables from the Machine target:
'        defaultEnvVar: (none)
'        processEnvVar: (none)
'        userEnvVar: (none)
'        machineEnvVar: (none)
'
'      Deleting environment variables for each target...

注解

有关此 API 的详细信息，请参阅 Environment.GetEnvironmentVariable 的补充 API 备注。

另请参阅

适用于

通过

Environment.GetEnvironmentVariable 方法

定义

重载

GetEnvironmentVariable(String)

参数

返回

例外

示例

注解

另请参阅

适用于

GetEnvironmentVariable(String, EnvironmentVariableTarget)

参数

返回

例外

示例

注解

另请参阅

适用于

其他资源