I am using these lines of code to check if the record exists or not.
SqlCommand check_User_Name = new SqlCommand(\"SELECT * FROM Table WHERE ([user] = \'\" +
Use try catch:
try { SqlCommand check_User_Name = new SqlCommand("SELECT * FROM Table WHERE ([user] = '" + txtBox_UserName.Text + "') ", conn); int UserExist = (int)check_User_Name.ExecuteScalar(); // Update query } catch { // Insert query }