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Control.NamingContainer Property

Gets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same Control.ID property value.

Namespace:  System.Web.UI
Assembly:  System.Web (in System.Web.dll)

public virtual Control NamingContainer { get; }

Property Value

Type: System.Web.UI.Control
The server control's naming container.

Each page in an ASP.NET Web application contains a hierarchy of controls. This hierarchy is not dependent on whether a control generates UI visible to the user. The naming container for a given control is the parent control above it in the hierarchy that implements the INamingContainer interface. A server control that implements this interface creates a unique namespace for the ID property values of its child server controls.

Creating a unique namespace for server controls is particularly important when you bind data against list Web server controls, such as the Repeater and DataList server controls. When multiple entries in the data source create multiple instances of a server control that is a child of the repeating control, the naming container ensures that each instance of these child controls have UniqueID property values that do not conflict. The default naming container for a page is the instance of the Page class generated when that page is requested.

You can use this property to determine the naming container where a specific server control is located.

The following example demonstrates using the NamingContainer property.

<% @ Import Namespace = "System.Data"  %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
<html xmlns="" >
            Control NamingContainer Example
<script language="C#" runat="server">
      // Build the DataSource.
      ICollection CreateDataSource()
         DataTable myDataTable = new DataTable();
         DataRow myDataRow;
         myDataTable.Columns.Add(new DataColumn("EmployeeName", typeof(string)));
         for (int i = 0; i < 10; i++) 
            myDataRow = myDataTable.NewRow();
            myDataRow[0] = "somename" + i.ToString();
         DataView myDataView = new DataView(myDataTable);
         return myDataView;

      void Page_Load(Object sender, EventArgs e) 
         if (!IsPostBack) 
            // Bind 'DataView' to the DataSource.
            myDataList.DataSource = CreateDataSource();
         // Attach EventHandler for SelectedIndexChanged event.
         myDataList.SelectedIndexChanged += new EventHandler(selectedItemChanged);

      // Handler function for 'SelectedIndexChanged' event. 
      void selectedItemChanged(Object sender,EventArgs e)
         DataListItem myCurrentItem = myDataList.SelectedItem;
         Control myNamingContainer = myCurrentItem.Controls[0].NamingContainer;
         // Display the NamingContainer.
         myLabel1.Text = "The NamingContainer is : " + myNamingContainer.UniqueID;
         // Display the UniqueID.
         myLabel2.Text = "The UniqueID is : " + ((Control)(myCurrentItem.Controls[0])).UniqueID;

      <form runat="server" id="Form1">
            Control NamingContainer Example
            Click an item to view it's Naming Container and UniqueID
         <asp:Label ID="myLabel1" Runat="server"></asp:Label>
         <br />
         <asp:Label ID="myLabel2" Runat="server"></asp:Label>
         <br />
         <asp:DataList id="myDataList" runat="server" BorderColor="black">
            <HeaderStyle BackColor="#aaaadd"></HeaderStyle>
            <SelectedItemStyle BackColor="lightgreen"></SelectedItemStyle>
               <asp:LinkButton id="button1" Text='<%# DataBinder.Eval(Container.DataItem, "EmployeeName") %>' CommandName="select" runat="server" />

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0