ListControl.AppendDataBoundItems Property (System.Web.UI.WebControls)

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.NET Framework Class Library
ListControl.AppendDataBoundItems Property

Gets or sets a value that indicates whether list items are cleared before data binding.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)
Syntax
Visual Basic
<ThemeableAttribute(False)> _
Public Overridable Property AppendDataBoundItems As Boolean
C#
[ThemeableAttribute(false)]
public virtual bool AppendDataBoundItems { get; set; }
Visual C++
[ThemeableAttribute(false)]
public:
virtual property bool AppendDataBoundItems {
	bool get ();
	void set (bool value);
}
F#
[<ThemeableAttribute(false)>]
abstract AppendDataBoundItems : bool with get, set
[<ThemeableAttribute(false)>]
override AppendDataBoundItems : bool with get, set
ASP.NET
<asp:ListControl AppendDataBoundItems="True|False" />

Property Value

Type: System.Boolean
true if list items are not cleared before data binding; otherwise, false, if the items collection is cleared before data binding is performed. The default is false.
Remarks

The AppendDataBoundItems property allows you to add items to the ListControl object before data binding occurs. After data binding, the items collection contains both the items from the data source and the previously added items.

The value of this property is stored in view state.

This property cannot be set by themes or style sheet themes. For more information, see ThemeableAttribute and ASP.NET Themes and Skins.

Examples

The following code example demonstrates how to include both data-bound items and items that are not data-bound in a ListBox control. In the Load event for the Page, one item is added to the Items collection and the AppendDataBoundItems property is set to true. Then, the ListBox control is bound to a DataTable control. The resulting ListBox control contains both the data-bound items and the item that was added individually.

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
 <script language="vb" runat="server">

    Function CreateDataSource() As ICollection
        Dim dt As New DataTable()
        Dim dr As DataRow

        dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
        dt.Columns.Add(New DataColumn("DateTimeValue", GetType(DateTime)))
        dt.Columns.Add(New DataColumn("BoolValue", GetType(Boolean)))
        dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))

        Dim i As Integer
        For i = 0 To 8
            dr = dt.NewRow()

            dr(0) = i
            dr(1) = "Item " + i.ToString()
            dr(2) = DateTime.Now
            If (i Mod 2) <> 0 Then
                dr(3) = True
            Else
                dr(3) = False
            End If
            dr(4) = 1.23 *(i + 1)

            dt.Rows.Add(dr)
        Next i

        Dim dv As New DataView(dt)
        Return dv
    End Function

    Sub Page_Load(sender As Object, e As EventArgs)
         If Not IsPostBack Then
             RadioButtonList1.Items.Add("Non-databound item.")
             RadioButtonList1.AppendDataBoundItems = True
             RadioButtonList1.DataSource = CreateDataSource()
             RadioButtonList1.DataTextField = "StringValue"
             RadioButtonList1.DataValueField = "CurrencyValue"
             RadioButtonList1.DataBind()
         End If
    End Sub

    Sub Index_Changed(sender As Object, e As EventArgs)        
        Label1.Text = "You selected " & RadioButtonList1.SelectedItem.Text & _
            " with a value of : " & RadioButtonList1.SelectedItem.Value & "."
    End Sub

 </script>

 <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>

    <form id="form1" runat="server">

       <asp:RadioButtonList id="RadioButtonList1" 
            OnSelectedIndexChanged="Index_Changed"
            AutoPostBack="true"
            runat="server"/>

       <br />

       <asp:Label id="Label1" runat="server"/>

    </form>

 </body>
 </html>
C#

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
 <script language="c#" runat="server">

    ICollection CreateDataSource() {
       DataTable dt = new DataTable();
       DataRow dr;

       dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
       dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
       dt.Columns.Add(new DataColumn("DateTimeValue", typeof(DateTime)));
       dt.Columns.Add(new DataColumn("BoolValue", typeof(bool)));
       dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));

       for (int i = 0; i < 9; i++) {
          dr = dt.NewRow();

          dr[0] = i;
          dr[1] = "Item " + i.ToString();
          dr[2] = DateTime.Now;
          dr[3] = (i % 2 != 0) ? true : false;
          dr[4] = 1.23 * (i+1);

          dt.Rows.Add(dr);
       }

       DataView dv = new DataView(dt);
       return dv;
    }

    void Page_Load(Object sender, EventArgs e) {
       if (!IsPostBack) {
          RadioButtonList1.Items.Add("Non-databound item.");
          RadioButtonList1.AppendDataBoundItems = true;
          RadioButtonList1.DataSource = CreateDataSource();
          RadioButtonList1.DataTextField="StringValue";
          RadioButtonList1.DataValueField="CurrencyValue";
          RadioButtonList1.DataBind();
       }
    }

    void Index_Changed(Object sender, EventArgs e) {

       Label1.Text = "You selected " + RadioButtonList1.SelectedItem.Text +
                     " with a value of $" + RadioButtonList1.SelectedItem.Value +
                     ".";

    }

 </script>

 <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>

    <form id="form1" runat="server">

       <asp:RadioButtonList id="RadioButtonList1" 
            OnSelectedIndexChanged="Index_Changed"
            AutoPostBack="true"
            runat="server"/>

       <br />

       <asp:Label id="Label1" runat="server"/>

    </form>

 </body>
 </html>
Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
See Also

Reference

ListControl Class
System.Web.UI.WebControls Namespace
DataSource