C# how to restrict textbox decimal places to 2?

Question

I have this textbox where the decimal place should only be two, it works but it disables the back space afterwards

  try
        {
            if (string.IsNullOrWhiteSpace(textBox1.Text))
            {
                textBox2.Clear();
            }
            else
            {
                if (Convert.ToDouble(textBox1.Text) > Convert.ToDouble(grandTotal.Text))
                {
                    double change = Convert.ToDouble(textBox1.Text) - Convert.ToDouble(grandTotal.Text);
                    textBox2.Text = change.ToString("#,0.00");
                }
                else if (Convert.ToDouble(textBox1.Text) == Convert.ToDouble(grandTotal.Text))
                {
                    textBox2.Text = "0";
                }
                else
                {
                    textBox2.Clear();
                }
            }
        }
        catch(Exception)
        {

        }

When this code gets executed,? Tried exploring masked textbox? — Chetan, Sep 20 '17 at 01:25
Please **insert deity here**, teach the C# programmers of the world to stop doing `catch (Exception)` - it's a anti-pattern. — Enigmativity, Sep 20 '17 at 04:14

score 1 · Answer 1 · answered Sep 20 '17 at 03:08

You can do this on textbox KeyPress Event Handler:

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (e.KeyChar == '.' && textBox1.Text.Contains('.'))
            e.Handled = true;
        if (char.IsNumber(e.KeyChar) || e.KeyChar == '.')
        {
            if (Regex.IsMatch(
             textBox1.Text,
             "^\\d*\\.\\d{2}$")) e.Handled = true;
        }
        else e.Handled = e.KeyChar != (char)Keys.Back;
    }

Basically what it does is it limits the decimal places to two, it also limits decimal point into one. But the backspace should be working fine still.

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

0

Also you have alternative option rather than coding on selected control (textBox1). You can create reusable custom text box controller. This will guide you Decimal Textbox in Windows Forms

edited Jun 20 '20 at 09:12

Community

1
1

answered Sep 20 '17 at 04:06

dinesh subasingha

11
4

C# how to restrict textbox decimal places to 2?

2 Answers2

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