[DllImport("kernel32.dll")]
static extern IntPtr GetConsoleWindow();

[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

const int SW_HIDE = 0;
const int SW_SHOW = 5;

// Usage:
var handle = GetConsoleWindow();

// Hide
ShowWindow(handle, SW_HIDE);

// Show
ShowWindow(handle, SW_SHOW);