下面的代码示例演示如何以编程方式使用 CatalogDisplayMode 字段。代码使用受页支持的显示模式（在此示例中是浏览、设计和目录模式）填充一个下拉列表。由于网页中的 <asp:CatalogZone> 元素及其子元素，目录模式可用。注意，在 Page_PreRender 方法中，代码会检查当前 DisplayMode 属性是否设置为 CatalogDisplayMode。如果是，则 Label1 将可见；否则 Label1 将隐藏。
<%@ Page Language="VB" %>
<script runat="server">
Protected Sub Page_Init(ByVal sender As Object, _
ByVal e As EventArgs)
Dim mode As WebPartDisplayMode
For Each mode In mgr.SupportedDisplayModes
Dim modeName As String = mode.Name
If mode.IsEnabled(mgr) Then
Dim item As ListItem = New ListItem(modeName, modeName)
DisplayModeDropdown.Items.Add(item)
End If
Next
End Sub
Protected Sub DisplayModeDropdown_SelectedIndexChanged(ByVal _
sender As Object, ByVal e As EventArgs)
Dim selectedMode As String = _
DisplayModeDropdown.SelectedValue
Dim mode As WebPartDisplayMode = _
mgr.SupportedDisplayModes(selectedMode)
If mode IsNot Nothing Then
mgr.DisplayMode = mode
End If
End Sub
Protected Sub Page_PreRender(ByVal sender As Object, _
ByVal e As System.EventArgs)
If mgr.DisplayMode.Equals(WebPartManager.CatalogDisplayMode) Then
Label1.Visible = True
Else
Label1.Visible = False
End If
End Sub
</script>
<html >
<head id="Head1" runat="server">
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:WebPartManager ID="mgr" runat="server">
</asp:WebPartManager>
<asp:WebPartZone ID="WebPartZone1" runat="server">
<ZoneTemplate>
<asp:BulletedList
DisplayMode="HyperLink"
ID="BulletedList1"
runat="server"
Title="My Links">
<asp:ListItem Value="http://www.microsoft.com">
Microsoft
</asp:ListItem>
<asp:ListItem Value="http://www.msn.com">
MSN
</asp:ListItem>
<asp:ListItem Value="http://www.contoso.com">
Contoso Corp.
</asp:ListItem>
</asp:BulletedList>
</ZoneTemplate>
</asp:WebPartZone>
<asp:WebPartZone ID="WebPartZone2" runat="server" />
<asp:CatalogZone ID="CatalogZone1" runat="server">
<ZoneTemplate>
<asp:DeclarativeCatalogPart
ID="DeclarativeCatalogPart1"
runat="server">
<WebPartsTemplate>
<asp:Calendar ID="Calendar1" runat="server"
Title="My Calendar" />
</WebPartsTemplate>
</asp:DeclarativeCatalogPart>
</ZoneTemplate>
</asp:CatalogZone>
<hr />
<asp:Label ID="Label1" runat="server"
Text="Currently in Catalog Mode"
Font-Bold="true"
Font-Size="125%" />
<br />
<asp:DropDownList ID="DisplayModeDropdown"
runat="server"
AutoPostBack="true"
Width="120"
OnSelectedIndexChanged=
"DisplayModeDropdown_SelectedIndexChanged">
</asp:DropDownList>
</div>
</form>
</body>
</html>
<%@ Page Language="C#" %>
<script runat="server">
protected void Page_Init(object sender, EventArgs e)
{
foreach (WebPartDisplayMode mode in mgr.SupportedDisplayModes)
{
string modeName = mode.Name;
if (mode.IsEnabled(mgr))
{
ListItem item = new ListItem(modeName, modeName);
DisplayModeDropdown.Items.Add(item);
}
}
}
protected void DisplayModeDropdown_SelectedIndexChanged(object
sender, EventArgs e)
{
String selectedMode = DisplayModeDropdown.SelectedValue;
WebPartDisplayMode mode =
mgr.SupportedDisplayModes[selectedMode];
if (mode != null)
mgr.DisplayMode = mode;
}
protected void Page_PreRender(object sender, EventArgs e)
{
if (mgr.DisplayMode == WebPartManager.CatalogDisplayMode)
Label1.Visible = true;
else
Label1.Visible = false;
}
</script>
<html >
<head runat="server">
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:WebPartManager ID="mgr" runat="server">
</asp:WebPartManager>
<asp:WebPartZone ID="WebPartZone1" runat="server">
<ZoneTemplate>
<asp:BulletedList
DisplayMode="HyperLink"
ID="BulletedList1"
runat="server"
Title="My Links">
<asp:ListItem Value="http://www.microsoft.com">
Microsoft
</asp:ListItem>
<asp:ListItem Value="http://www.msn.com">
MSN
</asp:ListItem>
<asp:ListItem Value="http://www.contoso.com">
Contoso Corp.
</asp:ListItem>
</asp:BulletedList>
</ZoneTemplate>
</asp:WebPartZone>
<asp:WebPartZone ID="WebPartZone2" runat="server" />
<asp:CatalogZone ID="CatalogZone1" runat="server">
<ZoneTemplate>
<asp:DeclarativeCatalogPart
ID="DeclarativeCatalogPart1"
runat="server">
<WebPartsTemplate>
<asp:Calendar ID="Calendar1" runat="server"
Title="My Calendar" />
</WebPartsTemplate>
</asp:DeclarativeCatalogPart>
</ZoneTemplate>
</asp:CatalogZone>
<hr />
<asp:Label ID="Label1" runat="server"
Text="Currently in Catalog Mode"
Font-Bold="true"
Font-Size="125%" />
<br />
<asp:DropDownList ID="DisplayModeDropdown"
runat="server"
AutoPostBack="true"
Width="120"
OnSelectedIndexChanged=
"DisplayModeDropdown_SelectedIndexChanged">
</asp:DropDownList>
</div>
</form>
</body>
</html>
默认情况下，在浏览器中加载页后会处于浏览模式。注意，页上的标签是隐藏的。使用下拉列表控件将页切换至目录模式。注意，由于 Page_PreRender 方法中的代码，该标签现在可见。可以在目录中选择控件，再将它添加至页上两个区域中的任何一个中。