How to Bind Data to ComboBox from Database in Windows Forms application C#.net || How to Set Default Select Item in ComboBox 0th index.

To bind data to ComboBox in Windows forms follow the steps below:

First Design form with One ComboBox from toolbox in visualstudio.

Then write one ComboBoxBind() method in code behind side and call that method in form load.

Form.cs Code :

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Data.SqlClient;

namespace combox_binding

{

    public partial class Form1 : Form

    {

        SqlConnection con = new SqlConnection("Data Source=naresh;Initial Catalog=employee;User ID=sa;Password=123");

        public Form1()

        {

            InitializeComponent();

            ComboBoxBind ();

        }

        private void ComboBoxBind ()

        {

            con.Open();

            SqlDataAdapter da = new SqlDataAdapter("Select empID,empname from emp", con);

            DataTable dt = new DataTable();

            da.Fill(dt);

            DataRow dr;

            dr = dt.NewRow();

            dr.ItemArray = new object[] { 0, "---Select an item---" };

            dt.Rows.InsertAt(dr, 0);

            comboBox1.DisplayMember = "empname";

            comboBox1.ValueMember = "empID";

            comboBox1.DataSource = dt;

            con.Close();

        }

    }

}

Then run the application and see the data will be bind to ComboBox.

OutPut :