How to bind DropDownlist using Xml file in ASP.NET

XML File Introduction

XML file is a text file. basically XML file is used for carry data.
Features of XML file
1. Its a Case sensitive language.
2. Use User defined tags
3. Used for communication purpose
4. Its not a presentation language .
5. Same as HTML language.
6. Use Tree based architecture

The DropDownList control displays the list of data as a drop-down list from which you can make a single selection. The DropDownList control exists within the System.Web.UI.WebControls namespace. You cannot select multiple items in this control because when you make a selection from the list, the list closes automatically.
The DropDownList control has no non-inherited methods or events. This class inherited the ListControl class.

Public Properties of DropDownList Class

SelectedIndex : Obtains or sets the index of the selected item in the control.

Application of DropDownList Control

• In Registration page where you can select your country in given DropDownList.
• In management project where you can select single option in given options.

Lets take an simple example to bind DropdownList 

Step-1. Create a XML file with <Countries> tag.

<?xml version="1.0" encoding="utf-8" ?>

<Countries>

  <country>

    <countryId>101</countryId>

    <countryName>USA</countryName>

   

  </country>

  <country>

    <countryId>102</countryId>

    <countryName>India</countryName>

  </country>

  <country>

    <countryId>103</countryId>

    <countryName>UK</countryName>

  </country> 

 

 

</Countries>

Step-2 : Drag one DropdownList from ToolBox and Drop to design window.

Step-3 : Create a DataSet instance 

Step-4 : Read XML file by ReadXML() method

Step-5 :Bind DropdownList with DataSet Instance.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

public partial class Default3 : System.Web.UI.Page

{

    protected voidPage_Load(object sender, EventArgs e)

    {

        DataSet ds = new DataSet();

      

        ds.ReadXml(Server.MapPath("countries.xml"));

        DropDownList1.DataSource = ds;

        DropDownList1.DataTextField = "countryName";

        DropDownList1.DataValueField = "countryId";

        DropDownList1.DataBind();

       

    }

}

Output