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مشاهدة النسخة كاملة : SQL error



C# Programming
11-11-2009, 08:22 AM
Hi,

I am using a text box on the UI to query the database using the entered text.
Following is the code snippet

string refNum = (from Example in db.Orders
where Example.Reference == textBox1.Text
select Example.OrderId).First().ToString();

My question is..

How to show a friendly error message if Example.Reference is not equal to input value in textBox OR if no value is entered into the text field ?

Because am getting this error "{"Sequence contains no elements"}" when no value is entered or if any wrong value is eneterd. Can any1 tell me how to catch this error and show it as a friendly message to the user.

Thanks,