problem with databinding xml list to asp.net dropdownlist

I have this xml file, and now i will want to add new entries to my xml file

Before:

 <?xml version="1.0" encoding="utf-8"?>
<email>
  <builderemail>
    <builder>
      <id>1</id>
      <value>builder@xyz.com</value>
    </builder>
  </builderemail>
  <managerem开发者_运维百科ail>
    <manager>
      <id>1</id>
      <value>manager@xyz.com</value>
    </manager>
    </manageremail>
</email>

After:

 <?xml version="1.0" encoding="utf-8"?>
<email>
  <builderemail>
    <builder>
      <id>1</id>
      <value>builder@xyz.com</value>
      <id>2</id>
      <value>Others</value>
    </builder>
  </builderemail>
  <manageremail>
    <manager>
      <id>1</id>
      <value>manager@xyz.com</value>
      <id>2</id>
      <value>Others</value>
    </manager>
    </manageremail>
</email>

my code c# codes:

protected void Page_Load(object sender, EventArgs e)
{
    TextBox1.Visible = false;
    Button1.Visible = false;
    TextBox2.Visible = false;
    Button2.Visible = false;
    if (!IsPostBack)
    {
        PopulateDDLFromXMLFile();
    }
}
public void PopulateDDLFromXMLFile()
{
    DataSet ds = new DataSet();
    ds.ReadXml(MapPath("~/App_Data/builderemail.xml"));

    //get the dataview of table "Country", which is default table name
    DataView dv = ds.Tables["builder"].DefaultView;
    DataView dw = ds.Tables["manager"].DefaultView;
    //or we can use:
    //DataView dv = ds.Tables[0].DefaultView;

    //Now sort the DataView vy column name "Name"
    dv.Sort = "value";

    //now define datatext field and datavalue field of dropdownlist
    DropDownList1.DataTextField = "value";
    DropDownList1.DataValueField = "ID";
    DropDownList2.DataTextField = "value";
    DropDownList2.DataValueField = "ID";

    //now bind the dropdownlist to the dataview
    DropDownList1.DataSource = dv;
    DropDownList1.DataBind();
    DropDownList2.DataSource = dw;
    DropDownList2.DataBind();
}

However, this does not work. I will get a IndexOutOfRangeException error. how do i handle this?

The "IndexOutOfRange" exception is because of this line of code:

dv.Sort = "value"; //because the Table "builder" doesn't have the "value" column

The method PopulateDDLFromXMLFile works with the first version of xml. The later version of xml is not a valid one and doesn't represent what you want to / trying to do in PopulateDDLFromXMLFile method.

DataSet ds = new DataSet();
ds.ReadXml(MapPath("~/App_Data/builderemail.xml"));

Calling above code on the newer xml creates 6 tables, one for builderemail, builder, id, value, manageremail and manager.

But the code assumes that id and value would be columns inside builder table. Hence the above exception.

I would suggest you modify the xml as:

<?xml version="1.0" encoding="utf-8" ?>
<email>
    <builderemail>
        <builder>
            <id>1</id>
            <value>builder@xyz.com</value>
        </builder>
        <builder>
            <id>2</id>
            <value>Others</value>
            </builder>
    </builderemail>
    <manageremail>
        <manager>
            <id>1</id>
            <value>manager@xyz.com</value>
        </manager>
            <manger>
                <id>2</id>
                <value>Others</value>
            </manger>
    </manageremail>
</email>