Capture command line output (by character output, not having to wait per line)

Question

I\'m currently rendering the output of a command line process into a text box. The problem is that in a normal command prompt window, one of the lines that is written has a load

Answer 1

If you want asynchronous processing of the stdout of the given process on a per-character basis, you can use the TextReader.ReadAsync() method. Instead of the code you have to handle the OutputDataReceived event, just do something like this:

process.Start();

// Ignore Task object, but make the compiler happy
var _ = ConsumeReader(process.StandardOutput);

process.StandardInput.WriteLine( arguments.Command );
process.StandardInput.WriteLine( "exit" );

where:

async Task ConsumeReader(TextReader reader)
{
    char[] buffer = new char[1];

    while ((await read.ReadAsync(buffer, 0, 1)) > 0)
    {
        // process character...for example:
        Console.Write(buffer[0]);
    }
}

Alternatively, you could just create a dedicated thread and use that to call TextReader.Read() in a loop:

process.Start();

new Thread(() =>
{
    int ch;

    while ((ch = process.StandardOutput.Read()) >= 0)
    {
        // process character...for example:
        Console.Write((char)ch);
    }
}).Start();

process.StandardInput.WriteLine( arguments.Command );
process.StandardInput.WriteLine( "exit" );

IMHO the latter is more efficient, as it doesn't require as much cross-thread synchronization. But the former is more similar to the event-driven approach you would have had with the OutputDataReceived event.