How to filter datagridview using multiple combobox c#?

Question

Hi all!

 

I am very new to coding and am trying to learn C# through little project. I spent a week or more trying to find solution but although there is many threads, none of them made sense for me and couldn't get it to work.

I have a form with datagridview and I want to create 6 comboboxes to filter it. All with same data source. I managed so far to get datagridview working with one combobox but don't know how to add more of them.

I'd much appreciate you help. 

Below is the code:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Data.SqlClient;

 

namespace TM_Hub

{

   public partial class frmEmpList : Form

   {

      public frmEmpList()

      {

         InitializeComponent();

      }

      private void frmEmpList_Load(object sender, EventArgs e)

      {

         this.PopulateCombobox();

         this.PopulateDataGridView();

      }

      private void PopulateCombobox()

      {

         string qry = "SELECT DISTINCT LastName FROM Employees";

         string constr = @"Data Source=DESKTOP-Q2B3UUH\SQLEXPRESS;Initial          Catalog=PeopleManager;Integrated Security=True";

         using (SqlConnection con = new SqlConnection(constr))

         {

            using (SqlDataAdapter sda = new SqlDataAdapter(qry, con))

            {

               DataTable dt = new DataTable();

               sda.Fill(dt);

               DataRow row = dt.NewRow();

               row[0] = "";

               dt.Rows.InsertAt(row, 0);

               cbLastName.DataSource = dt;

               cbLastName.DisplayMember = "LastName";

               cbLastName.ValueMember = "LastName";

              }

           }

      }

      private void PopulateDataGridView()

      {

         string query = "SELECT EmpID, FirstName, LastName, Role, Grade, Dept, Shift          FROM Employees";

         query += " WHERE LastName = @LastName";

         query += " OR ISNULL(@LastName, '') = ''";

         string constr = @"Data Source=DESKTOP-Q2B3UUH\SQLEXPRESS;Initial          Catalog=PeopleManager;Integrated Security=True";

         using (SqlConnection con = new SqlConnection(constr))

         {

            using (SqlCommand cmd = new SqlCommand(query, con))

            {

               cmd.Parameters.AddWithValue("@LastName", cbLastName.SelectedValue);

               using (SqlDataAdapter sda = new SqlDataAdapter(cmd))

               {

                  DataTable dt = new DataTable();

                  sda.Fill(dt);

                  dgEmpList.DataSource = dt;

               }

            }

         }

      }

      private void cbLastName_SelectionChangeCommitted(object sender, EventArgs e)

      {

         this.PopulateDataGridView();

      }

   }

}

 

 

Many thanks in advance!