Unable to capture console screen

[zoebpatra]

Hi , 

Like how we can drag and select in putty , I am unable to capture the console screen output ( created using screen section ) using select all from the mouse click.

Please advise if any suggestions or alternative to capture the contents of screen in Visual COBOL .Net Environment ( Managed Code).

Regards,

Zoeb

[Chris Glazier]

You can use the standard Windows Print Screen key to copy the desktop image to the clipboard or if you use Alt-Print Screen it will copy the current active window instead. You can also use the Windows Snipping tool to mark a partial area of the screen to copy or there are countless other 3rd party tools to do the same.

Is this what you are looking for?

[zoebpatra]

No , I want to capture/read the context of the screen for Automation validations.

[zoebpatra]

We are trying to read the console output of the desired screen . Is there a way to read the console screen output through c# programatically .  

[Chris Glazier]

I found one example of how to read the console buffer programmatically in C# that also appears to work for COBOL. In this example I left the C# piece in C# instead of translating it to COBOL. I believe there are other ways of doing this as well but this seemed to work OK.

COBOL Console application:

       program-id. Program1 as "readconsolebuffer.Program1".
       data division.
       working-storage section.
       01 field-1  pic x(10) value "test".
       01 field-2  pic x(10) value "chris".
       screen section.
       01 myscreen blank screen.
          05       pic x(5) value "Name:" line 5 column 1.
          05       pic x(10) using field-1 line 5 column 8.   
          05       pic x(8) value "Company:" line 7 column 1.
          05       pic x(10) using field-2 line 7 column 10.   
       procedure division.
       
           display myscreen
           accept myscreen
         *> read 10 lines from the top of the console buffer
           perform varying myline as string thru type csReadBuffer.ConsoleReader::ReadFromBuffer(0, 0, type Console::BufferWidth as binary-short, 10)
              display myline
           end-perform
        
           goback.
           
       end program Program1.

C# utility class:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace csReadBuffer
{
    public class ConsoleReader
    {
        public static IEnumerable ReadFromBuffer(short x, short y, short width, short height)
        {
            IntPtr buffer = Marshal.AllocHGlobal(width * height * Marshal.SizeOf(typeof(CHAR_INFO)));
            if (buffer == null)
                throw new OutOfMemoryException();

            try
            {
                COORD coord = new COORD();
                SMALL_RECT rc = new SMALL_RECT();
                rc.Left = x;
                rc.Top = y;
                rc.Right = (short)(x + width - 1);
                rc.Bottom = (short)(y + height - 1);

                COORD size = new COORD();
                size.X = width;
                size.Y = height;

                const int STD_OUTPUT_HANDLE = -11;
                if (!ReadConsoleOutput(GetStdHandle(STD_OUTPUT_HANDLE), buffer, size, coord, ref rc))
                {
                    // 'Not enough storage is available to process this command' may be raised for buffer size > 64K (see ReadConsoleOutput doc.)
                    throw new Win32Exception(Marshal.GetLastWin32Error());
                }

                IntPtr ptr = buffer;
                for (int h = 0; h < height; h++)
                {
                    StringBuilder sb = new StringBuilder();
                    for (int w = 0; w < width; w++)
                    {
                        CHAR_INFO ci = (CHAR_INFO)Marshal.PtrToStructure(ptr, typeof(CHAR_INFO));
                        char[] chars = Console.OutputEncoding.GetChars(ci.charData);
                        sb.Append(chars[0]);
                        ptr += Marshal.SizeOf(typeof(CHAR_INFO));
                    }
                    yield return sb.ToString();
                }
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
            }
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct CHAR_INFO
        {
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
            public byte[] charData;
            public short attributes;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct COORD
        {
            public short X;
            public short Y;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct SMALL_RECT
        {
            public short Left;
            public short Top;
            public short Right;
            public short Bottom;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct CONSOLE_SCREEN_BUFFER_INFO
        {
            public COORD dwSize;
            public COORD dwCursorPosition;
            public short wAttributes;
            public SMALL_RECT srWindow;
            public COORD dwMaximumWindowSize;
        }

        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool ReadConsoleOutput(IntPtr hConsoleOutput, IntPtr lpBuffer, COORD dwBufferSize, COORD dwBufferCoord, ref SMALL_RECT lpReadRegion);

        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern IntPtr GetStdHandle(int nStdHandle);
    }
}