problem with 'if else' in c# winform

hi friends;
i am having a problem working with my loging form which i design in winform here is my code

private void btnLogin_Click(object sender, EventArgs e)
      {
          user = txtUsername.Text;
          pass = txtPassword.Text;
          role = cbRole.Text;
          SqlConnection con = new SqlConnection();
          con.ConnectionString = "Data Source=ESE-HP;Initial Catalog=PIMS;User ID=sa;PWD=ese";
          con.Open();
          SqlCommand cmd = new SqlCommand("select * from employee where  occupation = '" + role + "' and password = '" + pass + "' and username = '" + user + "' ", con);
          SqlDataReader dr = cmd.ExecuteReader();


          while (dr.Read())
          {
              if ((dr["Password"].ToString() == pass && dr["Username"].ToString() == user && dr["Occupation"].ToString() == role))
              {
                  messageBox.Show("Login Successful");
              }

             else
              {
                  MessageBox.Show("LOGIN NOT SUCCESSFUL );
              }
            }
      }

i have a login form that has username, password and role textbox when i run the code and enter my correct credentials, it displays the message "LOGIN SUCCESSFUL", but if i did not enter the correct information in the boxes, it wont display the 'else' message which is "LOGIN NOT SUCCESSFUL", i do not know what the problem is, can someone help me out? thanks.

Tags: C#