How to prevent the console to write a character in the last line?

Question

I have a problem with a console project of C#. I want to use the whole console screen to write text in it. Meaning, for example, to "draw" a border along the border of the console. The problem is the unnecessary last character in the last line. How can I prevent it?

For a better understanding, I've added a picture of the unwanted character.

I draw it by filling a two dimensional array of chars and dumping it with the following method. yMax is the height and xMax the width of the console window.

private void DumpCharacters()
    {
        for (int y = 0; y < yMax - 1; y++)
        {
            string line = string.Empty;
            for (int x = 0; x < xMax; x++)
            {
                line += characters[x, y];
            }
            Console.SetCursorPosition(0, y);
            Console.Write(line);
        }
    }

I already tried to increase the height of the border, but then, the mentioned character overwrites the border at that position.

EDIT: Sorry for my unclear explanation. Of course I meant, like Attila Bujáki said, the jump to the last line. Is it possible to prevent this?

Answer 1

If you want to fill the whole console window with your characters a possible way to go is to move back your cursor to the 0,0 position.

Example:

Console.CursorVisible = false;
for(int i = 0; i < Console.WindowHeight * Console.WindowWidth; i ++)
{
     Console.Write((i / Console.WindowWidth) % 10);  // print your stuff
}
Console.SetCursorPosition(0, 0);

Console.ReadKey();

So you could do it like this in your method:

private void DumpCharacters()
    {
        for (int y = 0; y < yMax; y++)
        {
            string line = string.Empty;
            for (int x = 0; x < xMax; x++)
            {
                line += characters[x, y];
            }
            Console.SetCursorPosition(0, y);
            Console.Write(line);
        }
        Console.SetCursorPosition(0, 0);
    }

Notice that you don't have to substract one from yMax. It is because now you can use the last line of the Console screen too.

Here is the full code to generate the desired outcome:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleChar
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Title = "Stackoverflow - Super example";
            Console.CursorVisible = false;

            int yMax = Console.WindowHeight;
            int xMax = Console.WindowWidth;
            char[,] characters= new char[Console.WindowWidth, Console.WindowHeight];

            for (int i = 0; i < Console.WindowWidth; i++ )
            {
                for (int j = 0; j < Console.WindowHeight; j++)
                {
                    char currentChar = ' ';

                    if((i == 0) || (i == Console.WindowWidth - 1))
                    {
                        currentChar = '║';
                    }
                    else
                    {
                        if((j == 0) || (j == Console.WindowHeight - 1))
                        {
                            currentChar = '═';
                        }
                    }                    

                    characters[i, j] = currentChar;
                }
            }

            characters[0, 0] = '╔';
            characters[Console.WindowWidth-1, 0] = '╗';
            characters[0, Console.WindowHeight - 1] = '╚';
            characters[Console.WindowWidth - 1, Console.WindowHeight - 1] = '╝';

                for (int y = 0; y < yMax ; y++)
                {
                    string line = string.Empty;
                    for (int x = 0; x < xMax; x++)
                    {
                        line += characters[x, y];
                    }
                    Console.SetCursorPosition(0, y);
                    Console.Write(line);
                }
            Console.SetCursorPosition(0, 0);
        }
    }
}

Answer 2

Use CursorVisible property of Console

Console.CursorVisible = false;

Answer 3

The accepted answer doesn't work if the Console buffer size is the same as the window size. As Phillip Scott Givens mentioned above, you have to use Console.MoveBufferArea writing to somewhere other than the bottom-right corner. This is the only way to solve the problem using the System.Console API even with Console.CursorVisible = false. Example code:

var w = Console.WindowWidth;
var h = Console.WindowHeight;
Console.SetBufferSize(w, h);

// Draw all but bottom-right 2 characters of box here ...

// HACK: Console.Write will automatically advance the cursor position at the end of each
// line which will push the buffer upwards resulting in the loss of the first line
var sourceReplacement = '═';
Console.SetCursorPosition(w - 2, h - 1); // bottom-right minus 1
Console.Write('╝');
// Move from bottom-right minus 1 to bottom-right overwriting the source
// with the replacement character
Console.MoveBufferArea(w - 2, h - 1, 1, 1, w - 1, h - 1,
    sourceReplacement, Console.ForegroundColor, Console.BackgroundColor);

If you're not fine with that, you can use the native console API (but it is Windows-only):

// http://pinvoke.net/default.aspx/kernel32/FillConsoleOutputCharacter.html
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool FillConsoleOutputCharacter(
    IntPtr hConsoleOutput,
    char cCharacter,
    uint nLength,
    COORD dwWriteCoord,
    out uint lpNumberOfCharsWritten
    );