I am writing a piece of code which asks for the age of the user. I have validated the input to only allow numerics, however to validate being between 16 and 90years old on .leave of txtBox an error has been made saying :

   Cast from string "" to type 'Double' is not valid.

Does anyone have a clue how to fix this...I have read up on the error but unfortunatly, because I am just new to programing, the terminology is way above me...I only understand the literal basics...Sorry!
Please help me!!
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The variable you think has the age really has a blank string (""), and when you treat it as a number it produces the error. So...

1. Your not reading the appropriate variable
2. Your input is not reaching the correct place.

In any case, after you get the input you should first check if its not blank, like so:

if not strX = "" then
     'your code here...
end if

Can you send the code?

J

Thank you sooooo much for getting back to me. I have copied my code about an age below:

  'change the color of the text box if under 18 or over 90 years to draw attenion to the error
        If txtOrgAge.Text < 18 Or txtOrgAge.Text > 90 Then
            txtOrgAge.BackColor = System.Drawing.Color.Red
            MessageBox.Show("Sorry, you have to be between 18 and 90 to participate in this event", "MINIMUM AGE 18", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            txtOrgAge.Clear()
        End If

Can you see where I have gone wrong? Remeber that I have validated the txtbox to only input numeric data...is this the cause?
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