C#

// PInvokeTest.cs
using System;
using System.Runtime.InteropServices;

class PlatformInvokeTest
{
    [DllImport("msvcrt.dll")]
    public static extern int puts(string c);
    [DllImport("msvcrt.dll")]
    internal static extern int _flushall();

    public static void Main() 
    {
        puts("Test");
        _flushall();
    }
}

Coding is a way of life.
It's in the air we breath.
It pumps through our veines.
Without it we soon crumble to dust.
    - Rodney S. Foley

<br />
[System.Runtime.InteropServices.DllImportAttribute("user32.dll")]<br />
private static extern uint SendInput(<br />
	uint nInputs,     // count of input events<br />
	INPUT[] pInputs,  // array of input events<br />
	int cbSize        // size of structure<br />
);<br />
<br />
public struct INPUT {<br />
  public int type;<br />
  public short wVk;<br />
  public short wScan;<br />
  public int dwFlags;<br />
  public int time;<br />
  public UIntPtr dwExtraInfo;<br />
  private int _pad0, _pad1;<br />
}<br />
<br />
I call it like this:<br />
<br />
INPUT[] ipar=new INPUT[1];<br />
INPUT m=new INPUT();<br />
ipar[0]=m;<br />
m.type= 1; //this is INPUT_KEYBOARD<br />
m.wVk= 0x41;  //this is VK_A<br />
m.wScan= 0; <br />
m.dwFlags=0;<br />
m.time=0;<br />
uint u=0;<br />
m.dwExtraInfo=(System.UIntPtr)u;<br />
tbx.Focus(); //tbx is a TextBox I created. <br />
uint ui=SendInput(1,ipar,System.Runtime.InteropServices.Marshal.SizeOf(m));<br />
<br />

if (tbx.InvokeRequired) tbx.Invoke(tbx.Focus);
else tbx.Focus();