DeclarativeCatalogPart.GetWebPart Method (WebPartDescription)
Returns a reference to a WebPart control based on the value of the description passed into the method.
Assembly: System.Web (in System.Web.dll)
Parameters
- description
-
Type:
System.Web.UI.WebControls.WebParts.WebPartDescription
A WebPartDescription that contains details about the control.
Return Value
Type: System.Web.UI.WebControls.WebParts.WebPartA WebPart control whose description matches the values in description.
| Exception | Condition |
|---|---|
| ArgumentNullException | Description is null. |
| ArgumentException | Description is not an available WebPartDescription instance. |
The GetWebPart method returns a reference to a WebPart control whose description details match the values of the WebPartDescription object passed into the method. Typically, this method is used together with the GetAvailableWebPartDescriptions method, which is used to retrieve the descriptions of all the controls in the catalog. Individual WebPart controls can then be retrieved or manipulated as needed by passing individual WebPartDescription objects to the GetWebPart method.
The following code example shows how to use the GetWebPart method. This example has four parts:
A user control that enables you to change display modes on a Web Parts page.
A source code file that contains two custom WebPart controls.
A Web page that contains a CatalogZone control and a DeclarativeCatalogPart control that references several server controls. The page also contains the event-handling code that calls the GetWebPart method.
An explanation of how the example works when you load the page in a browser.
The first part of this code example is the user control that enables users to change display modes on a Web page. For details about display modes and a description of the source code in this control, see Walkthrough: Changing Display Modes on a Web Parts Page.
<%@ control language="vb" classname="DisplayModeMenuVB"%> <script runat="server"> ' Use a field to reference the current WebPartManager. Dim _manager As WebPartManager Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs) AddHandler Page.InitComplete, AddressOf InitComplete End Sub Sub InitComplete(ByVal sender As Object, ByVal e As System.EventArgs) _manager = WebPartManager.GetCurrentWebPartManager(Page) Dim browseModeName As String = WebPartManager.BrowseDisplayMode.Name ' Fill the dropdown with the names of supported display modes. Dim mode As WebPartDisplayMode For Each mode In _manager.SupportedDisplayModes Dim modeName As String = mode.Name ' Make sure a mode is enabled before adding it. If mode.IsEnabled(_manager) Then Dim item As New ListItem(modeName, modeName) DisplayModeDropdown.Items.Add(item) End If Next mode ' If shared scope is allowed for this user, display the scope-switching ' UI and select the appropriate radio button for the current user scope. If _manager.Personalization.CanEnterSharedScope Then Panel2.Visible = True If _manager.Personalization.Scope = PersonalizationScope.User Then RadioButton1.Checked = True Else RadioButton2.Checked = True End If End If End Sub ' Change the page to the selected display mode. Sub DisplayModeDropdown_SelectedIndexChanged(ByVal sender As Object, _ ByVal e As EventArgs) Dim selectedMode As String = DisplayModeDropdown.SelectedValue Dim mode As WebPartDisplayMode = _ _manager.SupportedDisplayModes(selectedMode) If Not (mode Is Nothing) Then _manager.DisplayMode = mode End If End Sub ' Set the selected item equal to the current display mode. Sub Page_PreRender(ByVal sender As Object, ByVal e As EventArgs) Dim items As ListItemCollection = DisplayModeDropdown.Items Dim selectedIndex As Integer = _ items.IndexOf(items.FindByText(_manager.DisplayMode.Name)) DisplayModeDropdown.SelectedIndex = selectedIndex End Sub ' Reset all of a user's personalization data for the page. Protected Sub LinkButton1_Click(ByVal sender As Object, _ ByVal e As EventArgs) _manager.Personalization.ResetPersonalizationState() End Sub ' If not in User personalization scope, toggle into it. Protected Sub RadioButton1_CheckedChanged(ByVal sender As Object, _ ByVal e As EventArgs) If _manager.Personalization.Scope = PersonalizationScope.Shared Then _manager.Personalization.ToggleScope() End If End Sub ' If not in Shared scope, and if user is allowed, toggle the scope. Protected Sub RadioButton2_CheckedChanged(ByVal sender As Object, _ ByVal e As EventArgs) If _manager.Personalization.CanEnterSharedScope AndAlso _ _manager.Personalization.Scope = PersonalizationScope.User Then _manager.Personalization.ToggleScope() End If End Sub </script> <div> <asp:Panel ID="Panel1" runat="server" Borderwidth="1" Width="230" BackColor="lightgray" Font-Names="Verdana, Arial, Sans Serif" > <asp:Label ID="Label1" runat="server" Text=" Display Mode" Font-Bold="true" Font-Size="8" Width="120" AssociatedControlID="DisplayModeDropdown"/> <asp:DropDownList ID="DisplayModeDropdown" runat="server" AutoPostBack="true" Width="120" OnSelectedIndexChanged="DisplayModeDropdown_SelectedIndexChanged" /> <asp:LinkButton ID="LinkButton1" runat="server" Text="Reset User State" ToolTip="Reset the current user's personalization data for the page." Font-Size="8" OnClick="LinkButton1_Click" /> <asp:Panel ID="Panel2" runat="server" GroupingText="Personalization Scope" Font-Bold="true" Font-Size="8" Visible="false" > <asp:RadioButton ID="RadioButton1" runat="server" Text="User" AutoPostBack="true" GroupName="Scope" OnCheckedChanged="RadioButton1_CheckedChanged" /> <asp:RadioButton ID="RadioButton2" runat="server" Text="Shared" AutoPostBack="true" GroupName="Scope" OnCheckedChanged="RadioButton2_CheckedChanged" /> </asp:Panel> </asp:Panel> </div>
The second part of the code example is the source code for the two custom WebPart controls. For the code example to run, you must compile this source code. You can compile it explicitly and put the resulting assembly in your Web site's Bin folder or the global assembly cache. Alternatively, you can put the source code in your site's App_Code folder, where it will be dynamically compiled at run time. For a walkthrough that demonstrates both methods of compiling, see Walkthrough: Developing and Using a Custom Web Server Control.
Imports System Imports System.Collections Imports System.ComponentModel Imports System.Drawing Imports System.Security.Permissions Imports System.Web Imports System.Web.UI Imports System.Web.UI.WebControls Imports System.Web.UI.WebControls.WebParts Namespace Samples.AspNet.VB.Controls <AspNetHostingPermission(SecurityAction.Demand, _ Level:=AspNetHostingPermissionLevel.Minimal)> _ <AspNetHostingPermission(SecurityAction.InheritanceDemand, _ Level:=AspNetHostingPermissionLevel.Minimal)> _ Public Class UserInfoWebPart Inherits WebPart Private server As HttpServerUtility = HttpContext.Current.Server Private _userNickName As String = "Add a nickname." Private _userPetName As String = "Add a pet's name." Private _userSpecialDate As DateTime = DateTime.Now Private _userIsCurrent As [Boolean] = True Private _userJobType As JobTypeName = JobTypeName.Unselected Public Enum JobTypeName Unselected = 0 Support = 1 Service = 2 Professional = 3 Technical = 4 Manager = 5 Executive = 6 End Enum Private NickNameLabel As Label Private PetNameLabel As Label Private SpecialDateLabel As Label Private IsCurrentCheckBox As CheckBox Private JobTypeLabel As Label ' Add the Personalizable and WebBrowsable attributes to the ' public properties, so that users can save property values ' and edit them with a PropertyGridEditorPart control. <Personalizable(), WebBrowsable(), WebDisplayName("Nickname")> _ Public Property NickName() As String Get Dim o As Object = ViewState("NickName") If Not (o Is Nothing) Then Return CStr(o) Else Return _userNickName End If End Get Set(ByVal value As String) _userNickName = server.HtmlEncode(value) End Set End Property <Personalizable(), WebBrowsable(), WebDisplayName("Pet Name")> _ Public Property PetName() As String Get Dim o As Object = ViewState("PetName") If Not (o Is Nothing) Then Return CStr(o) Else Return _userPetName End If End Get Set(ByVal value As String) _userPetName = server.HtmlEncode(value) End Set End Property <Personalizable(), WebBrowsable(), WebDisplayName("Special Day")> _ Public Property SpecialDay() As DateTime Get Dim o As Object = ViewState("SpecialDay") If Not (o Is Nothing) Then Return CType(o, DateTime) Else Return _userSpecialDate End If End Get Set(ByVal value As DateTime) _userSpecialDate = value End Set End Property <Personalizable(), WebBrowsable(), WebDisplayName("Job Type")> _ Public Property UserJobType() As JobTypeName Get Dim o As Object = ViewState("UserJobType") If Not (o Is Nothing) Then Return CType(o, JobTypeName) Else Return _userJobType End If End Get Set(ByVal value As JobTypeName) _userJobType = CType(value, JobTypeName) End Set End Property <Personalizable(), WebBrowsable(), WebDisplayName("Is Current")> _ Public Property IsCurrent() As [Boolean] Get Dim o As Object = ViewState("IsCurrent") If Not (o Is Nothing) Then Return CType(o, [Boolean]) Else Return _userIsCurrent End If End Get Set(ByVal value As [Boolean]) _userIsCurrent = value End Set End Property Protected Overrides Sub CreateChildControls() Controls.Clear() NickNameLabel = New Label() NickNameLabel.Text = Me.NickName SetControlAttributes(NickNameLabel) PetNameLabel = New Label() PetNameLabel.Text = Me.PetName SetControlAttributes(PetNameLabel) SpecialDateLabel = New Label() SpecialDateLabel.Text = Me.SpecialDay.ToShortDateString() SetControlAttributes(SpecialDateLabel) IsCurrentCheckBox = New CheckBox() IsCurrentCheckBox.Checked = Me.IsCurrent SetControlAttributes(IsCurrentCheckBox) JobTypeLabel = New Label() JobTypeLabel.Text = Me.UserJobType.ToString() SetControlAttributes(JobTypeLabel) ChildControlsCreated = True End Sub Private Sub SetControlAttributes(ByVal ctl As WebControl) ctl.BackColor = Color.White ctl.BorderWidth = 1 ctl.Width = 200 Me.Controls.Add(ctl) End Sub Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter) writer.Write("Nickname:") writer.WriteBreak() NickNameLabel.RenderControl(writer) writer.WriteBreak() writer.Write("Pet Name:") writer.WriteBreak() PetNameLabel.RenderControl(writer) writer.WriteBreak() writer.Write("Special Date:") writer.WriteBreak() SpecialDateLabel.RenderControl(writer) writer.WriteBreak() writer.Write("Job Type:") writer.WriteBreak() JobTypeLabel.RenderControl(writer) writer.WriteBreak() writer.Write("Current:") writer.WriteBreak() IsCurrentCheckBox.RenderControl(writer) End Sub End Class <AspNetHostingPermission(SecurityAction.Demand, _ Level:=AspNetHostingPermissionLevel.Minimal)> _ <AspNetHostingPermission(SecurityAction.InheritanceDemand, _ Level:=AspNetHostingPermissionLevel.Minimal)> _ Public Class TextDisplayWebPart Inherits WebPart Private _contentText As String = Nothing Private _fontStyle As String = Nothing Private input As TextBox Private DisplayContent As Label Private lineBreak As Literal <Personalizable(), WebBrowsable()> _ Public Property ContentText() As String Get Return _contentText End Get Set(ByVal value As String) _contentText = value End Set End Property Protected Overrides Sub CreateChildControls() Controls.Clear() DisplayContent = New Label() DisplayContent.BackColor = Color.LightBlue DisplayContent.Text = Me.ContentText Me.Controls.Add(DisplayContent) lineBreak = New Literal() lineBreak.Text = "<br />" Controls.Add(lineBreak) input = New TextBox() Me.Controls.Add(input) Dim update As New Button() update.Text = "Set Label Content" AddHandler update.Click, AddressOf Me.submit_Click Me.Controls.Add(update) End Sub Private Sub submit_Click(ByVal sender As Object, _ ByVal e As EventArgs) ' Update the label string. If input.Text <> String.Empty Then _contentText = input.Text + "<br />" input.Text = String.Empty DisplayContent.Text = Me.ContentText End If End Sub End Class End Namespace
The third part of the example is the Web page that contains the DeclarativeCatalogPart control. Notice that the Button2_Click method obtains the descriptions of the WebPart controls in the catalog, calls the GetWebPart method to retrieve a control that matches the description of the third control in the collection, and then adds that control to the page.
<%@ page language="VB" %> <%@ register TagPrefix="uc1" TagName="DisplayModeMenuVB" Src="DisplayModeMenuVB.ascx" %> <%@ register tagprefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="UserInfoWebPartVB" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Protected Sub Page_Load(ByVal sender As Object, _ ByVal e As System.EventArgs) Button1.Visible = False Button2.Visible = False Label1.Visible = False End Sub Shared editControlTitle As String Protected Sub Button1_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) Dim descriptions As WebPartDescriptionCollection = _ DeclarativeCatalogPart1.GetAvailableWebPartDescriptions() Dim descriptionContent As StringBuilder = New StringBuilder() Dim description As WebPartDescription For Each description In descriptions descriptionContent.AppendLine("<div><br /><strong>" + _ description.Title + "</strong><br />") descriptionContent.AppendLine(" ID: " + _ description.ID + "<br />") descriptionContent.AppendLine(" Description: " + _ description.Description + "<br /></div><hr />") Next description Label1.Text = "<h3>Catalog Contents</h3>" + descriptionContent.ToString() End Sub Protected Sub Button2_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) Dim descriptions As WebPartDescriptionCollection = _ DeclarativeCatalogPart1.GetAvailableWebPartDescriptions() Dim partToAdd As WebPart = _ DeclarativeCatalogPart1.GetWebPart(descriptions(2)) WebPartManager1.AddWebPart(partToAdd, zone1, 0) End Sub Protected Sub DeclarativeCatalogPart1_PreRender(ByVal _ sender As Object, ByVal e As System.EventArgs) Button1.Visible = True Button2.Visible = True Label1.Visible = True End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title> DeclarativeCatalogPart Control </title> </head> <body> <form id="form1" runat="server"> <asp:webpartmanager id="WebPartManager1" runat="server" /> <uc1:DisplayModeMenuVB ID="DisplayModeMenu1" runat="server" /> <asp:webpartzone id="zone1" runat="server" > <PartTitleStyle BorderWidth="1" Font-Names="Verdana, Arial" Font-Size="110%" BackColor="LightBlue" /> <zonetemplate> <asp:BulletedList ID="BulletedList1" Runat="server" DisplayMode="HyperLink" Title="Favorites"> <asp:ListItem Value="http://msdn.microsoft.com"> MSDN </asp:ListItem> <asp:ListItem Value="http://www.asp.net"> ASP.NET </asp:ListItem> <asp:ListItem Value="http://www.msn.com"> MSN </asp:ListItem> </asp:BulletedList> </zonetemplate> </asp:webpartzone> <div> <hr /> <asp:Button ID="Button1" runat="server" Text="Display WebPart descriptions" OnClick="Button1_Click" /> <br /> <asp:Button ID="Button2" runat="server" Text="Add TextDisplayWebPart" OnClick="Button2_Click" /> <asp:Label ID="Label1" runat="server" Text="" /> </div> <asp:CatalogZone ID="CatalogZone1" runat="server"> <ZoneTemplate> <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1" runat="server" Title="Web Parts Catalog" ChromeType="TitleOnly" Description="Contains a user control with Web Parts and an ASP.NET Calendar control." OnPreRender="DeclarativeCatalogPart1_PreRender"> <WebPartsTemplate> <asp:Calendar ID="Calendar1" runat="server" Title="My Calendar" Description="ASP.NET Calendar control used as a personal calendar." /> <aspSample:UserInfoWebPart runat="server" id="userinfo1" title = "User Information WebPart" Description ="Contains custom, editable user information for display on a page." /> <aspSample:TextDisplayWebPart runat="server" id="TextDisplayWebPart1" title = "Text Display WebPart" Description="Contains a label where users can dynamically update the text." /> </WebPartsTemplate> </asp:DeclarativeCatalogPart> </ZoneTemplate> </asp:CatalogZone> </form> </body> </html>
When you load the page in a browser, select Catalog Mode in the Display Mode drop-down list control to switch to catalog mode. In catalog mode, you can see the controls that are available to be added to the page. If you click the Add TextDisplayWebPart button, the control is added to the page without your having to add it through the normal catalog user interface (UI). Use the Display Mode drop-down list to return the page to normal browse mode; the control you added is visible on the page.
Available since 2.0