How to update data C# to SQL via ADO.NET

using System.Data.SqlClient; SqlConnection cnn = new SqlConnection("Initial Catalog=Northwind;Data Source=localhost;Integrated Security=SSPI;"); private void button1_Click(object sender, EventArgs e) { cnn.Open(); SqlCommand cmd = new SqlCommand("UPDATE Employees SET FirstName = @CalisanAdi,LastName = @CalisanSoyadi WHERE EmployeeID = 1", cnn); cmd.Parameters.AddWithValue("@CalisanAdi", textBox1.Text); cmd.Parameters.AddWithValue("@CalisanSoyadi", textBox2.Text); cmd.ExecuteNonQuery(); cnn.Close(); }