Question

I have a input field that is supposed to take numbers only.

How can I validate the string?
Would this be ok:

string s = "12345";
double num;
bool isNum = double.TryParse(s, out num);

Or does .Net have a solution for this?

Answer 1

What you’ve done looks correct.

You could also create an extension method to make it easier:

    public static bool IsNumeric(this object _obj)
    {
        if (_obj == null)
            return false;

        bool isNum;
        double retNum;
        isNum = Double.TryParse(Convert.ToString(_obj), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);
        return isNum;
    }

So then you could do:

s.IsNumeric()