Having read above answers, GetConsoleWindow() can not be used. Instead GetStdHandle() must be used.
So here's a copy and paste class for enabling/disabling QuickEditMode. Call ConsoleWindow.QuickEditMode(false); to disable quick edit mode for the console window.
using System;
using System.Runtime.InteropServices;
public static class ConsoleWindow
{
    private static class NativeFunctions
    {
        public enum StdHandle : int
        {
            STD_INPUT_HANDLE = -10,
            STD_OUTPUT_HANDLE = -11,
            STD_ERROR_HANDLE = -12,
        }
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern IntPtr GetStdHandle(int nStdHandle); //returns Handle
        public enum ConsoleMode : uint
        {
            ENABLE_ECHO_INPUT = 0x0004,
            ENABLE_EXTENDED_FLAGS = 0x0080,
            ENABLE_INSERT_MODE = 0x0020,
            ENABLE_LINE_INPUT = 0x0002,
            ENABLE_MOUSE_INPUT = 0x0010,
            ENABLE_PROCESSED_INPUT = 0x0001,
            ENABLE_QUICK_EDIT_MODE = 0x0040,
            ENABLE_WINDOW_INPUT = 0x0008,
            ENABLE_VIRTUAL_TERMINAL_INPUT = 0x0200,
            //screen buffer handle
            ENABLE_PROCESSED_OUTPUT = 0x0001,
            ENABLE_WRAP_AT_EOL_OUTPUT = 0x0002,
            ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004,
            DISABLE_NEWLINE_AUTO_RETURN = 0x0008,
            ENABLE_LVB_GRID_WORLDWIDE = 0x0010
        }
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool GetConsoleMode(IntPtr hConsoleHandle, out uint lpMode);
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool SetConsoleMode(IntPtr hConsoleHandle, uint dwMode);
    }
    public static void QuickEditMode(bool Enable)
    {
        //QuickEdit lets the user select text in the console window with the mouse, to copy to the windows clipboard.
        //But selecting text stops the console process (e.g. unzipping). This may not be always wanted.
        IntPtr consoleHandle = NativeFunctions.GetStdHandle((int)NativeFunctions.StdHandle.STD_INPUT_HANDLE);
        UInt32 consoleMode;
        NativeFunctions.GetConsoleMode(consoleHandle, out consoleMode);
        if (Enable)
            consoleMode |= ((uint)NativeFunctions.ConsoleMode.ENABLE_QUICK_EDIT_MODE);
        else
            consoleMode &= ~((uint)NativeFunctions.ConsoleMode.ENABLE_QUICK_EDIT_MODE);
        consoleMode |= ((uint)NativeFunctions.ConsoleMode.ENABLE_EXTENDED_FLAGS);
        NativeFunctions.SetConsoleMode(consoleHandle, consoleMode);
    }
}