How to validate float variable in wpf textbox in both positive and negative

Question

How to validate float variable in wpf textbox in both positive and negative

Dinesh Kumar R 1

I tried with regular expression, it is not working, is there any pre-defined api, or binding with textbox or textbox property

Dinesh Kumar R 1

private void keyPress(object sender, TextCompositionEventArgs e)
{

        //e.Handled = false;
        /*           var regex = new Regex(@"[^0-9\s]");
                   Regex regex1 = new Regex(@"^-|^-?\d+(\.\d+)?$");
                   //e.Handled = !char.IsDigit(e.Text[0]);
                   if (!regex1.IsMatch(e.Text))
                   {
                       e.Handled = true;
                   }
       \*/
        //var regex1 = new Regex(@"^[0]{ 1 }$| ^[-]?[1 - 9]{ 1}\d *$");

    }

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Dinesh Kumar R 1 Reputation point

2022-04-21T16:54:17.853+00:00

private void keyPress(object sender, TextCompositionEventArgs e)
{

//e.Handled = false; /* var regex = new Regex(@"[^0-9\s]"); Regex regex1 = new Regex(@"^-|^-?\d+(\.\d+)?$"); //e.Handled = !char.IsDigit(e.Text[0]); if (!regex1.IsMatch(e.Text)) { e.Handled = true; } \*/ //var regex1 = new Regex(@"^[0]{ 1 }$| ^[-]?[1 - 9]{ 1}\d *$"); }

Answer 1

Viorel 122.5K

The validation can be done in this manner:

float f;
if( ! float.TryParse( textBox1.Text, out f ) )
{
    // Error. Show an error message or indicator
    // . . .
}
else
{
    // Success
    // . . .
}

It can be done after pressing the action button like "OK", "Save", etc.

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How to validate float variable in wpf textbox in both positive and negative

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