This blog demonstrates how to bind a drop down list control using xml file.
This is little simple process but it's very useful. First of all drag and drop a Drop Down List control on page.

<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="ddlTitle" runat="server"></asp:DropDownList>
</div>
</form>
</body>


Add a namespace on code behind.

using System.Data;

and write few lines of code on page load event to fill drop down list.

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet dataSet = new DataSet();
dataSet.ReadXml(Server.MapPath("Advertisements.xml"));
DataView dataView = dataSet.Tables[0].DefaultView;

//Note Title is a column name which you want to bind in drop down list.

dataView.Sort = "Title";
ddlTitle.DataTextField = "Title";
ddlTitle.DataValueField = "Title";

ddlTitle.DataSource = dataView;
ddlTitle.DataBind();
}
}

After compiling application you will see result like this.

img1.jpg