TextBox按键问题
各位大侠帮帮忙: 
 想实现捕捉TextBox中某个按键(如D),但是不显示D字母在TextBox中,又不清空之前的内容,该如何实现?   
------解决方案--------------------//用KeyPress事件处理,参考如下代码 
         private void textBox2_KeyPress(object sender, KeyPressEventArgs e) 
         { 
             switch (e.KeyChar) 
             { 
                 case  'd ': 
                 case  'D ': 
                     e.KeyChar =  '\0 '; 
                     break; 
             } 
         }
------解决方案--------------------TO:又不清空之前的内容是什么意思?   
 这样可以不?   
         private void textBox2_KeyPress(object sender, KeyPressEventArgs e) 
         { 
             e.Handled = (e.KeyChar == 'D ' || e.KeyChar == 'd ') ? true : false; 
         } 
------解决方案--------------------//e.Handled = (e.KeyChar == 'D ' || e.KeyChar == 'd ') ? true : false; 
 //e.Handled = (e.KeyChar == 'D ' || e.KeyChar == 'd '); //一样 
 //我用的是2005....那就用楼上的 
         private void textBox2_KeyPress(object sender, KeyPressEventArgs e) 
         { 
             e.Handled = char.ToUpper(e.KeyChar) ==  'D '; 
         }