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PageCatalogPart.GetAvailableWebPartDescriptions Method

Returns a collection of descriptions of the available WebPart controls in a catalog.

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

public override WebPartDescriptionCollection GetAvailableWebPartDescriptions()

Return Value

Type: System.Web.UI.WebControls.WebParts.WebPartDescriptionCollection
A WebPartDescriptionCollection that contains a WebPartDescription for each closed WebPart control in a page catalog.

The GetAvailableWebPartDescriptions method provides an implementation for the abstract base method declared in the CatalogPart class. The GetAvailableWebPartDescriptions method returns description information for each control in a catalog. A WebPartDescription object contains essential information about a WebPart control, including its ID, an object reference to the control, and the values of several important properties that are inherited from the Part class, such as Title and Description.

The GetAvailableWebPartDescriptions method improves performance. When a catalog is created, it needs some information about each control it contains, including a title, a description, an icon (if one exists), and an ID. Rather than having to create an instance of each control to get this information, a CatalogZoneBase zone that creates a catalog calls the GetAvailableWebPartDescriptions method for each control that will be in the catalog, and the call returns only the description information for the control.

The following code example shows how to use the GetAvailableWebPartDescriptions 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 PageCatalogPart control that references several server controls. The page also contains the event-handling code that calls the GetAvailableWebPartDescriptions 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="C#" classname="DisplayModeMenuCS"%>
<script runat="server">

 // Use a field to reference the current WebPartManager.
  WebPartManager _manager;

  void Page_Init(object sender, EventArgs e)
  {
    Page.InitComplete += new EventHandler(InitComplete);

  }  

  void InitComplete(object sender, System.EventArgs e)
  {
    _manager = WebPartManager.GetCurrentWebPartManager(Page);

    String browseModeName = WebPartManager.BrowseDisplayMode.Name;

    // Fill the dropdown with the names of supported display modes. 
    foreach (WebPartDisplayMode mode in _manager.SupportedDisplayModes)
    {
      String modeName = mode.Name;
      // Make sure a mode is enabled before adding it. 
      if (mode.IsEnabled(_manager))
      {
        ListItem item = new ListItem(modeName, modeName);
        DisplayModeDropdown.Items.Add(item);
      }
    }

    // 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)
    {
      Panel2.Visible = true;
      if (_manager.Personalization.Scope == PersonalizationScope.User)
        RadioButton1.Checked = true;
      else
        RadioButton2.Checked = true;
    }

  }

  // Change the page to the selected display mode. 
  void DisplayModeDropdown_SelectedIndexChanged(object sender, EventArgs e)
  {
    String selectedMode = DisplayModeDropdown.SelectedValue;

    WebPartDisplayMode mode = _manager.SupportedDisplayModes[selectedMode];
    if (mode != null)
      _manager.DisplayMode = mode;
  }

  // Set the selected item equal to the current display mode. 
  void Page_PreRender(object sender, EventArgs e)
  {
    ListItemCollection items = DisplayModeDropdown.Items;
    int selectedIndex = 
      items.IndexOf(items.FindByText(_manager.DisplayMode.Name));
    DisplayModeDropdown.SelectedIndex = selectedIndex;
  }

  // Reset all of a user's personalization data for the page. 
  protected void LinkButton1_Click(object sender, EventArgs e)
  {
    _manager.Personalization.ResetPersonalizationState();
  }

  // If not in User personalization scope, toggle into it. 
  protected void RadioButton1_CheckedChanged(object sender, EventArgs e)
  {
    if (_manager.Personalization.Scope == PersonalizationScope.Shared)
      _manager.Personalization.ToggleScope();
  }

  // If not in Shared scope, and if user is allowed, toggle the scope. 
  protected void RadioButton2_CheckedChanged(object sender, EventArgs e)
  {
    if (_manager.Personalization.CanEnterSharedScope && 
        _manager.Personalization.Scope == PersonalizationScope.User)
      _manager.Personalization.ToggleScope();
  }
</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="&nbsp;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.

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class UserInfoWebPart : WebPart
  {
    HttpServerUtility server = HttpContext.Current.Server;
    private String _userNickName = "Add a nickname.";
    private String _userPetName = "Add a pet's name.";
    private DateTime _userSpecialDate = DateTime.Now;
    private Boolean _userIsCurrent = true;
    private JobTypeName _userJobType = JobTypeName.Unselected;
    public enum JobTypeName
    {
      Unselected = 0,
      Support = 1,
      Service = 2,
      Professional = 3, 
      Technical = 4,
      Manager = 5,
      Executive = 6
    }
    Label NickNameLabel;
    Label PetNameLabel;
    Label SpecialDateLabel;
    CheckBox IsCurrentCheckBox;
    Label JobTypeLabel;

    // 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 String NickName
    {
      get 
      { 
        object o = ViewState["NickName"];
        if (o != null)
          return (string)o;
        else 
          return _userNickName;        
      } 

      set { _userNickName = server.HtmlEncode(value); }
    }

    [Personalizable(), WebBrowsable, WebDisplayName("Pet Name")]
    public String PetName
    {
      get 
      { 
        object o = ViewState["PetName"];
        if (o != null)
          return (string)o;
        else 
          return _userPetName;        
      }

      set { _userPetName = server.HtmlEncode(value); }
    }

    [Personalizable(), WebBrowsable(), WebDisplayName("Special Day")]
    public DateTime SpecialDay
    {
      get
      {
        object o = ViewState["SpecialDay"];
        if (o != null)
          return (DateTime)o;
        else 
          return _userSpecialDate;

      }

      set { _userSpecialDate = value; }
    }

    [Personalizable(), WebBrowsable(), WebDisplayName("Job Type")]
    public JobTypeName UserJobType
    {
      get
      {
        object o = ViewState["UserJobType"];
        if (o != null)
          return (JobTypeName)o;
        else 
          return _userJobType;
      }

      set { _userJobType = (JobTypeName)value; }
    }

    [Personalizable(), WebBrowsable(), WebDisplayName("Is Current")]
    public Boolean IsCurrent
    {
      get
      {
        object o = ViewState["IsCurrent"];
        if (o != null)
          return (Boolean)o;
        else 
          return _userIsCurrent;
      }

      set { _userIsCurrent = value; }
    }


    protected override void CreateChildControls()
    {
      Controls.Clear();

      NickNameLabel = new Label();
      NickNameLabel.Text = this.NickName;
      SetControlAttributes(NickNameLabel);

      PetNameLabel = new Label();
      PetNameLabel.Text = this.PetName;
      SetControlAttributes(PetNameLabel);

      SpecialDateLabel = new Label();
      SpecialDateLabel.Text = this.SpecialDay.ToShortDateString();
      SetControlAttributes(SpecialDateLabel);

      IsCurrentCheckBox = new CheckBox();
      IsCurrentCheckBox.Checked = this.IsCurrent;
      SetControlAttributes(IsCurrentCheckBox);

      JobTypeLabel = new Label();
      JobTypeLabel.Text = this.UserJobType.ToString();
      SetControlAttributes(JobTypeLabel);

      ChildControlsCreated = true;

    }

    private void SetControlAttributes(WebControl ctl)
    {
      ctl.BackColor = Color.White;
      ctl.BorderWidth = 1;
      ctl.Width = 200;
      this.Controls.Add(ctl);
    }

    protected override void RenderContents(HtmlTextWriter writer)
    {
      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);
    }
  }


  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class TextDisplayWebPart : WebPart
  {
    private String _contentText = null;
    TextBox input;
    Label DisplayContent;
    Literal lineBreak;

    [Personalizable(), WebBrowsable]
    public String ContentText
    {
      get { return _contentText; }
      set { _contentText = value; }
    }

    protected override void CreateChildControls()
    {
      Controls.Clear();
      DisplayContent = new Label();
      DisplayContent.BackColor = Color.LightBlue;
      DisplayContent.Text = this.ContentText;
      this.Controls.Add(DisplayContent);

      lineBreak = new Literal();
      lineBreak.Text = @"<br />";
      Controls.Add(lineBreak);

      input = new TextBox();
      this.Controls.Add(input);
      Button update = new Button();
      update.Text = "Set Label Content";
      update.Click += new EventHandler(this.submit_Click);
      this.Controls.Add(update);

    }

    private void submit_Click(object sender, EventArgs e)
    {
      // Update the label string. 
      if (input.Text != String.Empty)
      {
        _contentText = input.Text + @"<br />";
        input.Text = String.Empty;
        DisplayContent.Text = this.ContentText;
      }
    }

  }

}

The third part of the example is the Web page that contains the PageCatalogPart control. Notice that the Button1_Click method calls the GetAvailableWebPartDescriptions method, obtains the descriptions of the WebPart controls in the page catalog, and writes the details to a label.

<%@ page language="c#" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuCS" 
  Src="DisplayModeMenuCS.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.CS.Controls" 
  Assembly="UserInfoWebPartCS" %>

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

  protected void Page_Load(object sender, EventArgs e)
  {
    Button1.Visible = false;
    Button2.Visible = false;
    Label1.Visible = false;
  }

  protected void Button1_Click(object sender, EventArgs e)
  {
    WebPartDescriptionCollection descriptions =
      PageCatalogPart1.GetAvailableWebPartDescriptions();
    StringBuilder descriptionContent = new StringBuilder();
    foreach (WebPartDescription description in descriptions)
    {
      descriptionContent.AppendLine("<div><br /><strong>" + description.Title + 
        "</strong><br />");
      descriptionContent.AppendLine("&nbsp;ID: " + description.ID + "<br />");
      descriptionContent.AppendLine("&nbsp;Description: " + 
        description.Description + "<br /></div><hr />");
    }

    Label1.Text = "<h3>Catalog Contents</h3>" + descriptionContent.ToString();    
  }

  protected void Button2_Click(object sender, EventArgs e)
  {
    WebPartDescriptionCollection descriptions = 
      PageCatalogPart1.GetAvailableWebPartDescriptions();  

    if(descriptions.Count > 0)
    {
      ArrayList partList = new ArrayList();

      // Add the WebPart controls to a collection before you call  
      // AddWebPart on the WebPartManager.  If you try to add the  
      // controls directly by using AddWebPart, the WebPartAdded  
      // event fires each time you call AddWebPart, and it destroys   
      // the collection of descriptions before you finish adding  
      // all the WebPart controls. 
      foreach(WebPartDescription description in descriptions)
      {
        WebPart partToAdd = 
          PageCatalogPart1.GetWebPart(description);
        partList.Add(partToAdd);
      }

      foreach(WebPart part in partList)
      {
        WebPartManager1.AddWebPart(part, zone1, 0);
      }
    }  
  }

  protected void PageCatalogPart1_PreRender(object sender,
    EventArgs e)
  {
    Button1.Visible = true;
    Button2.Visible = true;
    Label1.Visible = true;
  }

</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:DisplayModeMenuCS 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 WebPart Controls" OnClick="Button2_Click" />
      <asp:Label ID="Label1" runat="server" Text="" />
      </div>
      <asp:CatalogZone ID="CatalogZone1" runat="server">
        <ZoneTemplate>
          <asp:PageCatalogPart ID="PageCatalogPart1" runat="server" 
            OnPreRender="PageCatalogPart1_PreRender" />
          <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1"  
            runat="server" 
            Description="Contains a user control with Web Parts and 
              an ASP.NET Calendar control." >
            <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. Add one or more controls to the page, and then use the Display Mode drop-down list control to return the page to browse mode. Click the verbs menu (the downward arrow) in the title bar of one or more of the controls, and click Close. Return the page to catalog mode, and notice that the control or controls you closed now appear in the page catalog, and are available to be added back to the page. Click the Display WebPart descriptions button to write the details about the controls in the page catalog to the label.

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
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