problem in select statement

I have a table called table1, it has 2 fields name and address.

now in visual c# windows application, i have two text boxes. if i enter value in tat text boxes, it should check with the table whether the value exists in the table, if it exist it should display message tat it already exists, if not it should  display tat value doesn't exist.

please help me out to solve this with a code snippet.