试试这个： -

Try This one :-

protected void Button1_Click(object sender, EventArgs e)
       {
           Con = new SqlConnection("Your Connection String");

           Con.Open();
           Cmd = new SqlCommand("update employee set 
           Emp_Name='"+TextBox1.Text+"' where Emp_ID=5",Con);
           

          
           if (Cmd.ExecuteNonQuery() > 0)
           {

                   Con.Close();
                   Response.Write("Done..");
           }


          
       }