c# fourms get live output from cmd line by line

Question

good evening all,

i have been working on getting output from cmd

however, i was wondering if there was a way to get output from cmd one line at a time

instead of it doing all the lines in one and reporting all at once.

System.Diagnostics.Process p = new System.Diagnostics.Process();

p.StartInfo.UseShellExecute = false;
p.StartInfo.FileName = "cmd.exe";
path = @"C:\test";
if(path == string.Empty)
{
string[] myargs = {example arguments};
string elfen = string.Join("", myargs);
XtraMessageBox.Show(elfen);
p.StartInfo.Arguments = string.Join("", elfen);
p.StartInfo.RedirectStandardError = true;
p.StartInfo.RedirectStandardInput = true;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.CreateNoWindow = true;
p.Start();

StreamReader outputWriter2 = p.StandardOutput;
//String errorReader = p.StandardError.ReadToEnd();
String line2 = outputWriter2.ReadLine();
while (line2 != null)
{
line2 = outputWriter2.ReadLine(); // ADDED
if (line2 != null)
{
splitstrings(line2);
}

}
p.WaitForExit();
}

but it gets to - StreamReader outputWriter2 = p.StandardOutput;
to here and waits for the process to report all

because at the moment it will wait for the process to end and then report it,
when i want it to report line then line

is this possible

thank you in advance
elfenliedtopfan5

Answer 1

Here is an example

using System.Diagnostics;  
using System.Text;  
  
namespace DotNetRunTimeProcessStartApp.Classes;  
  
internal class Operations  
{  
    public static async Task<(bool succcess, string, Exception localException)> Execute()  
    {  
        try  
        {  
  
            var start = new ProcessStartInfo  
            {  
                FileName = "powershell.exe",  
                RedirectStandardOutput = true,  
                Arguments = "dotnet --list-runtimes",  
                CreateNoWindow = true  
            };  
  
            using var process = Process.Start(start);  
            using var reader = process!.StandardOutput;  
  
            process.EnableRaisingEvents = true;  
  
            var lineData = await reader.ReadToEndAsync();  
            var items = lineData.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);  
  
            StringBuilder builder = new();  
            foreach (var item in items)  
            {  
                if (item.Contains("["))  
                {  
                    builder.AppendLine("   " + item.Substring(0, item.IndexOf("[", StringComparison.Ordinal) - 1));  
                }  
            }  
  
            return (true, builder.ToString(), null)!;  
        }  
        catch (Exception localException)  
        {  
  
            return (false, "Failed", localException);  
        }  
    }  
}  

Usage

internal partial class Program  
{  
    static async Task Main(string[] args)  
    {  
        AnsiConsole.MarkupLine("[yellow]Hello[/]");  
        var (success, details, localException) = await Operations.Execute();  
        if (success)  
        {  
            Console.WriteLine(details);  
        }  
        else if (localException is not null)  
        {  
            Console.WriteLine(localException.Message);  
        }  
        Console.ReadLine();  
    }  
}  

Edit

internal class Operations  
{  
public static async Task<(bool succcess, string, Exception localException)> Execute()  
{  
    try  
    {  
  
        var start = new ProcessStartInfo  
        {  
            FileName = "powershell.exe",  
            RedirectStandardOutput = true,  
            Arguments = "dotnet --list-runtimes",  
            CreateNoWindow = true  
        };  
  
  
        using (var process = Process.Start(start))  
        {  
            var reader = process!.StandardOutput;  
  
            process.EnableRaisingEvents = true;  
  
            var lineData = await reader.ReadToEndAsync();  
            var items = lineData.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);  
  
            StringBuilder builder = new();  
            foreach (var item in items)  
            {  
                if (item.Contains("["))  
                {  
                    builder.AppendLine("   " + item.Substring(0, item.IndexOf("[", StringComparison.Ordinal) - 1));  
                }  
            }  
  
            return (true, builder.ToString(), null)!;  
        }  
          
    }  
    catch (Exception localException)  
    {  
  
        return (false, "Failed", localException);  
    }  
}  

Answer 2

Are you sure you need to use cmd.exe? Probably not. You need it only if you are executing a command that is internal to the command shell, such as dir. Or a batch file.

See Process.OutputDataReceived Event. The following is a simplified version of what you are doing but should show a way to do it. It works for me.

static void Main(string[] args)  
{  
    Process p = new System.Diagnostics.Process();  
    p.StartInfo.UseShellExecute = false;  
    p.StartInfo.FileName = "entire path to exe";  
    p.StartInfo.Arguments = "argone argtwo";  
    p.StartInfo.RedirectStandardOutput = true;  
    p.OutputDataReceived += LiveOutputHandler;  
    p.Start();  
    p.BeginOutputReadLine();  
    p.WaitForExit();  
}  
  
private static void LiveOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)  
{  
    Console.WriteLine($"Received: {outLine.Data}");  
}