Bind DropDownList using Asp .Net C#

Hi this post explains how to bind "DownDownList  with sql data using as asp .Net c#".For this tutorial I am using Customers Table from Northwind database.To download Northwind data base follow the link .

The Html Markup

The Following Html Markup consist drop down list ans status label to show selection  value.

<div>

        <asp:Label ID="lblCity" runat="server" Text="City:"></asp:Label>

        <asp:DropDownList ID="ddlCity" runat="server" 

            onselectedindexchanged="ddlCity_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>

            <br />

            <br />

        <asp:Label ID="lblStatus" runat="server" Text=""></asp:Label>

    </div>

C# Code:

Following code bind the data to the dropdown list.

protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

        {

            this.BindDropDownList();

        }

    }

    private void BindDropDownList()

    {

        SqlConnection conn = Connection();

        SqlCommand cmd = new SqlCommand();

        cmd.CommandText = "SELECT DISTINCT City from Customers";

        cmd.Connection = this.Connection();

        DataTable dTable = new DataTable(); 

        SqlDataAdapter sqlAdapter = new SqlDataAdapter(cmd);

        sqlAdapter.Fill(dTable);

        ddlCity.DataSource = dTable;        

        ddlCity.DataTextField = "City";

        ddlCity.DataValueField = "City";

        ddlCity.DataBind();

        ddlCity.Items.Insert(0, new ListItem("--SELECT CITY--", "-1"));

    }

//Connection String object creation

    private SqlConnection Connection()

    {

        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

        SqlConnection conn = new SqlConnection(constr);

        return conn;

    }

DropDownList Selection Index Changed:

The following code get the selected item from the dropdown list and shows it on the label.

protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)

    {

        lblStatus.Text = "Selected City:" + ddlCity.SelectedItem.Text;        

    }

ConnectionString:

Place the following connection string in the web config file.

<connectionStrings>

    <add name="constr" connectionString="Data Source=(local);Initial Catalog=NORTHWND;Integrated Security=True"

        providerName="System.Data.SqlClient" />

</connectionStrings>

Output:

Download Source Code

Source Code