Get the console buffer without the last line with C#?

Question

What I'm trying to achieve is a self-compiled c# file without toxic output.I'm trying to achieve this with Console.MoveBufferArea method but looks does not work. Eg. - save the code below with .bat extension :

// 2>nul||@goto :batch
/*
:batch
@echo off
setlocal

:: find csc.exe
set "frm=%SystemRoot%\Microsoft.NET\Framework\"
for /f "tokens=* delims=" %%v in ('dir /b /a:d  /o:-n "%SystemRoot%\Microsoft.NET\Framework\v*"') do (
   set netver=%%v
   goto :break_loop
)
:break_loop
set csc=%frm%%netver%\csc.exe
:: csc.exe found
%csc% /nologo /out:"%~n0.exe" "%~dpsfnx0" 
%~n0.exe
endlocal
exit /b 0
*/
public class Hello
{
   public static void Main() {
      ClearC();
      System.Console.WriteLine("Hello, C# World!");
   }

   private static void ClearC() {
        System.Console.MoveBufferArea(
            0,0,
            System.Console.BufferWidth,System.Console.BufferHeight-1,
            0,0
        );
   }
}

the output will be:

C:\>//  2>nul  ||
Hello, C# World!

What want is to rid of the // 2>nul || .Is it possible? Is there something wrong in my logic (the ClearC method)?Do I need PInvoke?

@Jashaszun - I can do this even in batch portion with `cls` command but if possible I want to preserve the commands history.Just because it will be more smooth. — npocmaka, Jun 19 '15 at 22:39
This is a question related to batch commands/batch files, not C#... or? — , Jun 19 '15 at 22:44
@elgonzo - definetely `c#` - with batch commands I have no so sophisticated tools for console buffer manipulation. — npocmaka, Jun 19 '15 at 22:46
Try setting the cursor position with [Console.SetCursorPosition](http://msdn.microsoft.com/en-us/library/system.console.setcursorposition.aspx). As row you should probably use `Console.CursorTop-1` unless CursorTop is already 0 (e.g., `row = max(0, Console.CursorTop-1)`) -- this should place the cursor on the line with the `// 2>nul ||` fragment. Then output whatever lines you want and they should overwrite the fragment (make sure that the lines you write are at least as long as the fragment to completely overwrite it). Not sure whether it works, but worth a try, i guess... — , Jun 19 '15 at 23:07
Read It http://stackoverflow.com/questions/18060048/keep-console-readline-always-on-last-line — reza moradi, Jun 30 '15 at 08:47

score 3 · Accepted Answer · edited May 23 '17 at 11:59

If you want to do it in the C#, then changing your ClearC function to the following seems to work:

public static void ClearC() {
    System.Console.CursorTop = System.Console.CursorTop - 1;
    System.Console.Write(new string(' ', System.Console.BufferWidth));
    System.Console.CursorTop = System.Console.CursorTop - 1;
}

Essentially, move the Cursor up a line (to the line that should contain your prompt), blank the entire line, then move up another line (which should move you to the blank line between commands). Future output will then take place from here.

The obvious downside to this is that you need to wait for the C# code to be compiled and executed, before the // 2>nul || is removed. If you want it to be faster, you'll need to find a console/batch file based solution. The other thing to keep in mind is that is assumes that the prompt is a single line. If it's a really long prompt that spans two lines, then you'll get a bit of a mess, so it may be better to clear two lines, depending on how you're planning on using this.

If you want to go the whole hog and start reading the console buffer to determine how long the prompt is, then you might want to have a look at this question. Whilst the article link in the answer is broken, the code download still seems to work.

If you want to go down the batchfile based approach, then you might want to have a look at this question.

Thanks - this worked. Though seems I need also one try catch if the output is redirected. — npocmaka, Jun 24 '15 at 12:38

Get the console buffer without the last line with C#?

1 Answers1