实现:

this.textBox1.Focus(); 
   SendKeys.Send("asdjfkl;");//输入字符
  
    SendKeys.Send("^a");//ctrl+a,全选
  
    SendKeys.Send("{DEL}");//删除
  
    SendKeys.Send("+(ec)");//输入大写 EC
  
    SendKeys.Send("{ENTER}");//回车
  
    SendKeys.Send("+ec");//输入Ec
  
    SendKeys.Send("ec");//输入ec
  
    SendKeys.Send("{ENTER}");
  
    SendKeys.Send("{h 10}"); //输入10个h
  
    SendKeys.Send("{ENTER}");