以下是   SendKeys   的一些特殊键代码表。   
  键   代码     
  BACKSPACE   {BACKSPACE}、{BS}   或   {BKSP}     
  BREAK   {BREAK}     
  CAPS   LOCK   {CAPSLOCK}     
  DEL   或   DELETE   {DELETE}   或   {DEL}     
  DOWN   ARROW（下箭头键）   {DOWN}     
  END   {END}     
  ENTER   {ENTER}   或   ~     
  ESC   {ESC}     
  HELP   {HELP}     
  HOME   {HOME}     
  INS   或   INSERT   {INSERT}   或   {INS}     
  LEFT   ARROW（左箭头键）   {LEFT}     
  NUM   LOCK   {NUMLOCK}     
  PAGE   DOWN   {PGDN}     
  PAGE   UP   {PGUP}     
  PRINT   SCREEN   {PRTSC}（保留，以备将来使用）     
  RIGHT   ARROW（右箭头键）   {RIGHT}     
  SCROLL   LOCK   {SCROLLLOCK}     
  TAB   {TAB}     
  UP   ARROW（上箭头键）   {UP}     
  F1   {F1}     
  F2   {F2}     
  F3   {F3}     
  F4   {F4}     
  F5   {F5}     
  F6   {F6}     
  F7   {F7}     
  F8   {F8}     
  F9   {F9}     
  F10   {F10}     
  F11   {F11}     
  F12   {F12}     
  F13   {F13}     
  F14   {F14}     
  F15   {F15}     
  F16   {F16}     
  数字键盘加号   {ADD}     
  数字键盘减号   {SUBTRACT}     
  数字键盘乘号   {MULTIPLY}     
  数字键盘除号   {DIVIDE}         
  若要指定与   SHIFT、CTRL   和   ALT   键的任意组合一起使用的键，请在这些键代码之前加上以下一个或多个代码：   
  键   代码     
  SHIFT   +     （SHIFT="+")
  CTRL   ^     (CTRL="^") 如果输入
  ALT   %     
private void button1_Click(object sender, System.EventArgs e)
        {//英文输入
            this.richTextBox1.Focus();                                            
            for(int i=65;i<91;i++)
            {
                char Letter=(char)i;
                SendKeys.Send(Letter.ToString());
                System.Threading.Thread.Sleep(100);        
                SendKeys.Flush();
            }        
            for(int i=97;i<123;i++)
            {
                char Letter=(char)i;
                SendKeys.Send(Letter.ToString());
                System.Threading.Thread.Sleep(100);
                SendKeys.Flush();
            }        
        }
        private void button3_Click(object sender, System.EventArgs e)
        {//数字输入
            this.richTextBox1.Focus();                                            
            for(int i=0;i<10;i++)
            {               
                SendKeys.Send(i.ToString());
                System.Threading.Thread.Sleep(100);        
                SendKeys.Flush();
            }               
        }
        private void button4_Click(object sender, System.EventArgs e)
        {//Backspace
            this.richTextBox1.Focus();
            SendKeys.Send("{Backspace}");        
        }
        private void button5_Click(object sender, System.EventArgs e)
        {//Home
            this.richTextBox1.Focus();
            SendKeys.Send("{Home}");               
        }
        private void button6_Click(object sender, System.EventArgs e)
        {//End
            this.richTextBox1.Focus();
            SendKeys.Send("{End}");        
        }
        private void button7_Click(object sender, System.EventArgs e)
        {//Enter
            this.richTextBox1.Focus();
            SendKeys.Send("{Enter}");        
        }
        private void button8_Click(object sender, System.EventArgs e)
        {//Delete
            this.richTextBox1.Focus();
            SendKeys.Send("{Delete}");        
        }
        private void button2_Click(object sender, System.EventArgs e)
        {//Shift+Home
            this.richTextBox1.Focus();
            SendKeys.Send("+{Home}");               
        }
        private void button9_Click(object sender, System.EventArgs e)
        {//Shift+End
            this.richTextBox1.Focus();
            SendKeys.Send("+{End}");               
        }
 看下方法的说明
public class SendKeys : System.Object
    System.Windows.Forms 的成员
摘要:
 提供将键击发送到应用程序的方法。   
public static void Send ( System.String keys )
    System.Windows.Forms.SendKeys 的成员
摘要:
 向活动应用程序发送击键。   
public static void Sleep ( System.TimeSpan timeout )
    System.Threading.Thread 的成员
摘要:
 将当前线程阻塞指定的时间。   
public static void Flush (  )
    System.Windows.Forms.SendKeys 的成员