I have found many examples of coding on how to execute cmd.exe and execute a command, and execute even nslookup and interact, but the problem I am having is with a particular dos program that when it starts, it does not stop "outputting". here is some code and I will put a comment and the errors I get from C#
Here is how I have it setup in a more advanced way so I can receive output from the program on events
public void StartApplication(string appNameAndPath)
{
StreamReader outputStream;
Process p = new Process();
p.StartInfo.FileName = appNameAndPath;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.UseShellExecute = false;
p.StartInfo.CreateNoWindow = false;//for now just so I can see it
p.Start();
//here is my advanced example
if(advanced == true)
{
outputStream = p.StandardOutput;
DoReadOutPut();
}
else
{//here is a simple example
while (p.StandardOutput.ReadLine() != null) //this hangs here until the application exists
{
txt += (p.StandardOutput.ReadLine());
}
}
}
void DoReadOutput()
{
outputStream.BaseStream.BeginRead( readOutputBuffer, 0, readOutputBuffer.Length, new AsyncCallback( OnReadOutputCompleted ), null );
//this does sometimes fire but only with 0 bytes, on other dos programs it would say Memory read not allowed
}
void OnReadOutputCompleted( IAsyncResult result )
{
int cbRead = outputStream.BaseStream.EndRead( result );
ProcessOutput( readOutputBuffer, cbRead );
DoReadOutput();
}
private void ProcessOutput(byte[] buffer, int cbRead)
{
string text = p.StartInfo.StandardOutputEncoding.GetString(buffer, 0, 10000); //this is where it hangs until the program exits or is not writing anymore
this.Invoke((Action)delegate
{
SetTextBoxValue(text);//im doing this because im on another thread otherwise textBox1.Text - text"
});
}
I do not want to have to use API and GetText
and create an engine to ReadLastLine
, can anyone help me with this? I suppose you would want an example exe, creating a C# application that while(true){Console.WriteLine("bla");}
would suffice as the example exe but not the exe I am having trouble with. The exe takes over the dos window and has an "old school interface"
async/await can help here....
await Exec(yourExe,parameters);
Task Exec(string exe,string args)
{
var tcs = new TaskCompletionSource<object>();
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = exe;
psi.UseShellExecute = false;
psi.RedirectStandardOutput = true;
psi.Arguments = args;
var proc = Process.Start(psi);
proc.OutputDataReceived += (s, e) =>
{
this.Invoke((Action) (()=>richTextBox1.AppendText(e.Data + Environment.NewLine)));
};
proc.Exited += (s, e) => tcs.SetResult(null);
proc.EnableRaisingEvents = true;
proc.BeginOutputReadLine();
return tcs.Task;
}
You need to handle callback events to read streams:
startInfo.UseShellExecute = false;
startInfo.CreateNoWindow = true;
startInfo.RedirectStandardOutput = true;
startInfo.RedirectStandardError = true;
Process proc = new Process();
proc.StartInfo = startInfo;
proc.ErrorDataReceived += new DataReceivedEventHandler(DataReceiveHandler);
proc.OutputDataReceived += new DataReceivedEventHandler(DataReceiveHandler);
proc.Start();
proc.BeginErrorReadLine();
proc.BeginOutputReadLine();
proc.WaitForExit();
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