Question

这是:

http://msdn.microsoft.com/en-us/library/system.windows.forms. Control.keypress.aspx

...indicates that I should have access to e.KeyCode in the KeyPress event, but I don t seem to. I m trying to allow only 1,2,3, and backspace:

private void textBoxQH1_KeyPress(object sender, KeyPressEventArgs e) {
  if ((e.KeyChar !=  1 ) &&
      (e.KeyChar !=  2 ) &&
      (e.KeyChar !=  3 ) &&
      (e.KeyChar != (Keys.Back))) {
    e.Handled = true; 
  }
}

......但“......”没有像例子所示显示的“KeyCode”价值,也没有用钥匙审判Char。后面的老板,“主人!”不能适用于类型的果园和系统。 Windows.Forms.Keys “

因此,我如何能够做到这一点?

Answer 1

try comparing e.KeyChar != (char)Keys.Back, you should cast it to char since Keys is an enumeration

见http://msdn.microsoft.com/es-es/library/system.windows.forms.keypresseventargs.keychar%28v=vs80%29.aspx>KeyPressEventArgs.KeyChar 。

Answer 2

我确信,我只用<代码>KeyDown活动解决了这一问题;它有不同的活动理由。

Answer 3

提出这样的条件:

<><>Code>:

 if (e.KeyCode == (Keys.Back))
 {
        if(textBox1.Text.Length >=3)
        {
             if (textBox1.Text.Contains("-"))
             {
                 textBox1.Text.Replace("-", "");
             }
        }
 }

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