Create a cmd window and write to it from C# application
Your approach is wrong: You currently don't write to a console window. Instead you created a process by starting cmd.exe
and write to the standard input pipe of that process. cmd.exe
is not aware of that. It's not the same as typing in a console via your keyboard, and even that can have strange effects.
Imagine you output a new line character, so cmd.exe
might try to "execute" what you output before as a command.
The correct way is to invoke AllocConsole
. With this call you can create a console window for your process and use it simply via Console.WriteLine()
.
When you finished your work and logging, you'll eventually need to close and free this console again via FreeConsole
.
So import these two native methods:
internal sealed class NativeMethods
{
[DllImport("kernel32.dll")]
public static extern bool AllocConsole();
[DllImport("kernel32.dll")]
public static extern bool FreeConsole();
}
And use them in your code:
NativeMethods.AllocConsole();
// start work
Console.WriteLine("log messages...");
// finished work
NativeMethods.FreeConsole();
Note that FreeConsole()
will close the console window, so all your log messages get lost. And a console only has a so large buffer and you can't scroll back to older messages if the leave the buffer.
So it may be a better idea to simply write your log messages into a file that you can analyze later.
Comments
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Toivo Säwén almost 2 years
I am developing a C# component for Grasshopper for Rhino. As I am running some pretty heavy iterative analysis I would like to output results continuously to a cmd window just to make sure that the analysis is actually running.
Here's what I tried:
using System.Diagnostics; Result results = new Result(); Process cmd = new Process(); cmd.StartInfo.FileName = "cmd.exe"; cmd.StartInfo.RedirectStandardInput = true; cmd.StartInfo.RedirectStandardOutput = true; cmd.StartInfo.CreateNoWindow = false; cmd.StartInfo.UseShellExecute = false; cmd.Start(); do { results = RunHeavyOperation(results); cmd.StandardInput.WriteLine("echo " + results.usefulInfo); } while (!results.conditionForEnd); cmd.WaitForExit(); Result RunHeavyOperation(Result previousResults) { Result res = doHeavyStuff(previousResults); return res; }
I realise that I am missing part, but what is it?