仅屏蔽数字文本框,但不接受BackSpace

if (Char.IsControl(e.KeyChar) != true && Char.IsNumber(e.KeyChar) != true)
{
    e.Handled = true;
}

if (!Char.IsControl(e.KeyChar) && !Char.IsNumber(e.KeyChar))
{
    e.Handled = true;
}

private void amount_PaidTextBox_KeyPress(object sender, KeyPressEventArgs e)
{
    e.Handled = !сhar.IsNumber(e.KeyChar) && (e.KeyChar != '\b');
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
    string text = (sender as TextBox).Text;

    StringBuilder builder = new StringBuilder(String.Empty);

    foreach (char character in text)
    {
        if (Char.IsDigit(character))
        {
            builder.Append(character);
        }
    }

    (sender as TextBox).Text = builder.ToString();
}

private void amount_PaidTextBox_KeyPress(object sender, KeyPressEventArgs e)
{
     if (!Char.IsNumber(e.KeyChar) && e.KeyCode != Keys.Back)
          e.Handled = True;
}

 private void amount_PaidTextBox_KeyPress(object sender, KeyPressEventArgs e)
 {
   e.Handled = !(Char.IsNumber(e.KeyChar) || (e.KeyChar==Keys.Back));
 }

How to allow only numeric (0-9) in HTML inputbox using jQuery?

private void txt_KeyPress(object sender, KeyPressEventArgs e)
{
    if (Char.IsDigit(e.KeyChar) || e.KeyChar == '\b')
    {
        // Allow Digits and BackSpace char
    }        
    else
    {
        e.Handled = true;
    }
}

另请参阅链接: Masking Textbox to accept only decimals

      private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!Char.IsDigit(e.KeyChar) & (e.KeyChar != 8)) e.Handled = true; 
    }

从事件中双击KeyPress

if( e.KeyChar <'0' || e.KeyChar > '9' )
if(e.KeyChar!=08)
e.Handled=true;