Accept only numeric and float values in TextBox in Windows Application using Regular Expression

Hi ashishk,

You can use RegularExpressions for validation.

Check this example. Now please take its reference and correct your code.

For this example i have used TextBox KeyUp event. You can change it as per your requirement.

Form Design

Code

C#

private void txtNumber_KeyUp(object sender, KeyEventArgs e)
{
    if (txtNumber.Text.Length > 0)
    {
        System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex(@"^(?=.)([+-]?([0-9]*)(\.([0-9]+))?)$");
        System.Text.RegularExpressions.Match match = regex.Match(txtNumber.Text);
        if (match.Success)
        {
            MessageBox.Show("Valid");
        }
        else
        {
            MessageBox.Show("Invalid");
        }
    }
}

VB.Net

Private Sub txtNumber_KeyUp(ByVal sender As Object, ByVal e As KeyEventArgs)
    If txtNumber.Text.Length > 0 Then
        Dim regex As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex("^(?=.)([+-]?([0-9]*)(\.([0-9]+))?)$")
        Dim match As System.Text.RegularExpressions.Match = regex.Match(txtNumber.Text)
        If match.Success Then
            MessageBox.Show("Valid")
        Else
            MessageBox.Show("Invalid")
        End If
    End If
End Sub

Screenshot