protected void btnAdd_Click(object sender, EventArgs e)
{
double number;
bool isNumber = double.TryParse(txtNewNumber.Text, out number); // Testing if textbox value is numeric
if (isNumber) // if numeric add number to total
{
calc.Addition(number);
lblTotal.Text = (calc.Total).ToString();
}
else // Display error
{
txtNewNumber.Text = string.Empty;
txtNewNumber.Focus();
lblTotal.Text = "Please Enter A Numeric Value";
}
}