Binding to Asp DataSource components
RadDropDownList supports binding to all ASP.NET 2.0 DataSource components, including:
SqlDataSource
LinqDataSource
EntityDataSource
ObjectDataSource
XmlDataSource
To bind to a DataSource component, all you need to do is set the DataSourceID property of RadDropDownList to the ID of the DataSource component. You should also set the DataTextField and DataValueField properties of RadDropDownList to map the Text and Value properties of the items to the respective columns / fields from the data source.
If you need to map additional columns from the data source to properties of RadDropDownList items, you can use the ItemDataBound event. The event arguments passed to the event, e.Item and e.Item.DataItem, hold the instance of RadDropDownList item being bound and the DataItem to which it is bound. You can map a property from the DataItem to the corresponding property of RadDropDownList item. Be sure to cast the DataItem object to the proper data type first.
protected void RadDropDownList1_ItemDataBound(object o, DropDownListItemEventArgs e)
{
DataRowView dataSourceRow = (DataRowView)e.Item.DataItem;
e.Item.Enabled = (bool)dataSourceRow["Enabled"];
e.Item.Attributes["customAttribute"] = dataSourceRow["CustomAttribute"].ToString();
}
Protected Sub RadDropDownList1_ItemDataBound(o As Object, e As DropDownListItemEventArgs)
Dim dataSourceRow As DataRowView = DirectCast(e.Item.DataItem, DataRowView)
e.Item.Enabled = CBool(dataSourceRow("Enabled"))
e.Item.Attributes("customAttribute") = dataSourceRow("CustomAttribute").ToString()
End Sub
SqlDataSource
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ComboConnectionString %>"
SelectCommand="SELECT * FROM [Links]"></asp:SqlDataSource>
<telerik:raddropdownlist
id="RadDropDownList1"
runat="server"
datatextfield="Text"
datavaluefield="Value"
datasourceid="SqlDataSource1"
onitemdatabound="RadDropDownList1_ItemDataBound">
</telerik:raddropdownlist>
LinqDataSource
<asp:LinqDataSource runat="server" ID="LinqDataSource1" ContextTypeName="LinqToSqlReadOnly.NorthwindReadOnlyDataContext"
OrderBy="ContactName" Select="new (ContactName, City, ContactTitle)" TableName="Customers">
</asp:LinqDataSource>
<telerik:raddropdownlist
id="RadDropDownList2"
runat="server"
runat="server"
datasourceid="LinqDataSource1"
datatextfield="ContactName">
</telerik:raddropdownlist>
EntityDataSource
<asp:EntityDataSource ID="EntityDataSource1" runat="server" ConnectionString="name=NorthwindEntities35"
DefaultContainerName="NorthwindEntities35" EntitySetName="Customers" Select="it.[ContactName], it.[City], it.[ContactTitle]"
AutoPage="true" OrderBy="it.[ContactName]">
</asp:EntityDataSource>
<telerik:raddropdownlist
id="RadDropDownList3"
runat="server"
datasourceid="EntityDataSource1"
datatextfield="ContactName">
</telerik:raddropdownlist>
ObjectDataSource
<telerik:raddropdownlist
id="RadDropDownList4"
runat="server"
datavaluefield="ID"
datatextfield="Text"
datasourceid="ObjectDataSource1">
</telerik:raddropdownlist>
<asp:ObjectDataSource ID="ObjectDataSource1" TypeName="DropDownListDataObject" SelectMethod="GetItems"
runat="server"></asp:ObjectDataSource>
public class DropDownListDataObject
{
public DropDownListDataObject() { }
public static List<DropDownListDataItem> GetItems()
{
List<DropDownListDataItem> itemsList = new List<DropDownListDataItem>();
itemsList.Add(new DropDownListDataItem(1, "item 1"));
itemsList.Add(new DropDownListDataItem(2, "item 2"));
itemsList.Add(new DropDownListDataItem(3, "item 3"));
return itemsList;
}
public class DropDownListDataItem
{
private string _text;
private int _id;
public string Text
{
get
{
return _text;
}
set
{
_text = value;
}
}
public int ID
{
get
{
return _id;
}
set
{
_id = value;
}
}
public DropDownListDataItem(int id, string text)
{
_id = id;
_text = text;
}
}
}
Public Class DropDownListDataObject
Public Sub New()
End Sub
Public Shared Function GetItems() As List(Of DropDownListDataItem)
Dim itemsList As New List(Of DropDownListDataItem)()
itemsList.Add(New DropDownListDataItem(1, "item 1"))
itemsList.Add(New DropDownListDataItem(2, "item 2"))
itemsList.Add(New DropDownListDataItem(3, "item 3"))
Return itemsList
End Function
Public Class DropDownListDataItem
Private _text As String
Private _id As Integer
Public Property Text() As String
Get
Return _text
End Get
Set(value As String)
_text = value
End Set
End Property
Public Property ID() As Integer
Get
Return _id
End Get
Set(value As Integer)
_id = value
End Set
End Property
Public Sub New(id As Integer, text As String)
_id = id
_text = text
End Sub
End Class
End Class
XmlDataSource
<telerik:RadDropDownList
id="RadDropDownList5"
runat="server"
datasourceid="XmlDataSource1"
datatextfield="Text"
datavaluefield="Value">
</telerik:RadDropDownList>
<asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/ContentFile.xml"></asp:XmlDataSource>
When using an XmlDataSource, the XML file should have the format shown below:
<items>
<Item Text="New York" Value="1" />
<Item Text="Paris" Value="2" />
<Item Text="London" Value="3" />
</items>
You can also load the XML file directly, rather than using a DataSource component as an intermediary.