private void textBox3_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
//阻止从键盘输入键
e.Handled = true;
if(e.KeyChar>=‘0‘ && e.KeyChar <=‘9‘)
{ e.Handled = false; }
}
多条件的：
private void TxtUser_KeyPress(object sender, KeyPressEventArgs e)
{
//阻止从键盘输入键
e.Handled = true;
if ((e.KeyChar >= ‘0‘ && e.KeyChar <= ‘9‘) || (e.KeyChar == (char)8))
{ if ((e.KeyChar == (char)8))
{ e.Handled = false; return; }
else { int len = TxtUser.Text.Length; if (len < 5)
{ if (len == 0 && e.KeyChar != ‘0‘)
{ e.Handled = false; return; }
else if(len == 0)
{ MessageBox.Show("编号不能以0开头！");
return; }
e.Handled = false; return; }
else { MessageBox.Show("编号最多只能输入5位数字！");
}
}
} else { MessageBox.Show("编号只能输入数字！");
}
}
//控制智能输入小数
private string perText;
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
var text = textBox1.Text;
double result;
Double.TryParse(textBox1.Text, out result);
if (result != 0)
{
perText = text;
}
else
{
textBox1.Text = perText;
this.textBox1.SelectionStart = this.textBox1.Text.Length;
this.textBox1.Focus();
}
}