Filling Dropdown box using Code-Behinds in C#

ASP CODE

By: aspfree	Search For More Articles! Disclaimer Author Terms
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2003-01-01

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Code-Behinds in C#

This simple example shows how to use code-behinds in ASP.NET. The following code fills a dropdown box selecting data from the pubs database. This is an example method of separating presentation from business logic.

Here is the code:

The webpage.

<%@ Page Language="C#" Debug="False" Inherits="myCodeBehind" src="2.cs"%>
<html>
<head><title>Fill dropdown with C# and Sql DataReader</title></head>
       <body>
           <asp:Dropdownlist id="atMyDropDownList" DataValueField = "au_lname" DataTextField = "au_id" runat="server" />
       </body>
</html>

The Code-behind page

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public class myCodeBehind : System.Web.UI.Page
{
public DropDownList atMyDropDownList;

    private void Page_Load(object sender, System.EventArgs e)
    {
        string sqlText = "select * from authors";
        atMyDropDownList.DataSource = GetDr( sqlText );
        atMyDropDownList.DataBind();
    }
    private SqlDataReader GetDr( string sqlText)
    {
        SqlDataReader dr;
        SqlConnection sqlConn = new SqlConnection(ConnectionString());
        SqlCommand sqlCmd = new SqlCommand(sqlText,sqlConn);
        sqlCmd.Connection.Open();
        dr = sqlCmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
        return dr;
    }
    private string ConnectionString()
        {
            return ConfigurationSettings.AppSettings["DSN_pubs"];
        }

    private void Page_Init( object Sender, System.EventArgs e)
    {

    }//end Page_Init

} //End Class

Web.Config holding application settings

DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware.

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