Validate TextBox control for float value

chandrabhan pradhan

Hi Techies,

I am making a windows form.

I am trying to validate a text box to accept only float value. Below is the code, where txtPurchasePrice is my textBox. The code below works fine:-

private void txtPurchasePrice_TextChanged(object sender, EventArgs e)
        {

            txtPurchasePrice.KeyPress += new KeyPressEventHandler(rtbQuantity_KeyPress);
        }

        private void rtbQuantity_KeyPress(object sender, KeyPressEventArgs e)
        {
            ////if ((e.KeyChar >= '0') || (e.KeyChar <= '9'))
            ////    e.Handled = true;

            if (!char.IsNumber(e.KeyChar) & (Keys)e.KeyChar != Keys.Back
            & e.KeyChar != '.')
            {
                e.Handled = true;
            }

            base.OnKeyPress(e);

        }

Problem: It accepts only first letter as alphabet, rest is OK. (means not working on first entered letter)

Help Plzz.
-------------------------------
Chandrabhan Pradhan
[email protected]

3 Replies

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Wim Sturkenboom12y ago
I'm not sure in which event I would put it; possibly 'Leave' event when the textbox looses the focus (so user input is assumed to be complete).

Code:
float f;

if (!float.TryParse(txtPurchasePrice.Text, f))
{
// not a valid float
}
Nilesh Wagh12y ago
This code works for numbers like 555.55 but user accidentally entered 555..55 then it stops execution.Can you please reply for the same?
Hirendra Sisodiya16y ago
Hello Chandrabhan
Why are you not using direct keypress event for txtPurchasePrice.
if you want to using common function you can try like this:
private void txtPurchasePrice_KeyPress(object sender, KeyPressEventArgs e)
{
Validate(e);
}

private void Validate(KeyPressEventArgs E)
{
if (!char.IsNumber(E.KeyChar) & (Keys)E.KeyChar != Keys.Back
& E.KeyChar != '.')
{
E.Handled = true;
}
}

thanks
Please mark as answere if it helps