0 Hi,
In a button click event
you simply check like
firstname.Text.Lengh<1
or firstname.Text==""
[firstname refers Textbox]...
for zip
if(zip.Text.Length==5))
{
//add you code
}
else
MessageBox.Show("zip must be 5 chars","Error");
[zip refers Textbox]
you can combine these conditions with the help of && operator
try it..