Check whether variable value is Numeric or not.

private void NumericCheckMethod()
{
    var inputString = "DotNetFunda";
    if (!IsNumeric(inputString))
    {
        MessageBox.Show("Valid WebSite.");
    }
    var fundaUserId = "12345";
    if (IsNumeric(fundaUserId))
    {
        MessageBox.Show("Valid User.");
    }
}

/// <summary>
/// Check whether a provided input is numeric or not.
/// </summary>
/// <param name="input"></param>
/// <returns>True: if input is numeric</returns>
private bool IsNumeric(object input)
{
    var isNumeric = false;
    int actualValue;
    if (input != null && int.TryParse(input.ToString(), out actualValue))
    {
        isNumeric = true;
    }

    return isNumeric;
}