Validate Textbox with Regular Expressions

Question

I had originally posted this in the Powershell forums since my entire script is in Powershell, but they had recommend I post it here.

I want to restrict the characters that the user inputs into a textbox on a form I have created. I want it restricted from between 7 and 11 digits (0-9). I am trying to use either regular expressions or a MaskedTextBox. I had almost gotten it to work with a MaskedTextBox, but then how do I validate it? My impression was that it would check as soon as focus is lost but that was not the case.

My knowledge of C# is very minimal so any dumbing down would be appreciated.

Answer 1

I do not test this code yet, but i believe that might help you

//allow only integer numbers

string nume = @"^\d+$";

//or

string num2 = @"^[0-9]+$";
Match match = Regex.Match("10", num2);

Label1.Text = "invalid";

if (match.Success)
{
  Label1.Text = "valid";
}

Answer 2

Or you even can try some logic looks like this

string valueFromTextBox = txt.Text;

if (Regex.IsMatch(valueFromTextBox , @"^[0-9]*$"))
{
  //works
}

Answer 3

Here is a code for you:

private void myTextBox_Leave(object sender, EventArgs e)
{
    Regex pattern = new Regex("[0-9]{7,11}");
    if (pattern.IsMatch(myTextBox.Text))
    {
        MessageBox.Show("OK");
    }
    else
    {
        MessageBox.Show("Invalid input");
    }
}

Noam B.

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