//SignIn private void button1_Click(object sender, EventArgs e) { try { command = "SELECT UserName, Password, LastName, CustomerId FROM Customer.dbo.Customer WHERE UserName='******' AND Password='******'"; SelectData(command); if (usernamecheck.Contains(textBox1.Text) && passwordcheck.Contains(textBox2.Text)) { this.Visible = false; Shop objShop = new Shop(); objShop.Show(); } else { throw new Exception("Please check again your 'User Name' and 'Password'!"); } } catch (Exception ex) { MessageBox.Show(ex.Message.ToString()); } }