If using TextBox2.Text
as the source for a numeric value, it must first be checked to see if a value exists, and then converted to integer.
If the text box is blank when Convert.ToInt32
is called, you will receive the System.FormatException
. Suggest trying:
protected void SetImageWidth()
{
try{
Image1.Width = Convert.ToInt32(TextBox1.Text);
}
catch(System.FormatException)
{
Image1.Width = 100; // or other default value as appropriate in context.
}
}