Question

Hello Fellow C# and Windows phone developers,

For my windows phone application, I have a textfield requiring the user to enter their age. During debugging mode I entered the number .8. and clicked proceed and the application unexpectedly closed. What code do I need to add so I can post a message box informing the user that numbers with more than 1 decimal point is unacceptable. Please Help

Answer 1

Assuming the input is a string, try:

if (input.IndexOf('.') == -1 || input.LastIndexOf('.') == input.IndexOf('.'))
{
    //good
}
else
    MessageBox.Show("More than one decimal point");

A better way though would be to use TryParse which will check the number for formatting

float age;
if (float.TryParse(input, out age))
{
    //good
}
else
    MessageBox.Show("Invalid age.");