ImportCatalogPart.GetAvailableWebPartDescriptions Method

Reference

Definition

Namespace:: System.Web.UI.WebControls.WebParts

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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

public:
 override System::Web::UI::WebControls::WebParts::WebPartDescriptionCollection ^ GetAvailableWebPartDescriptions();

public override System.Web.UI.WebControls.WebParts.WebPartDescriptionCollection GetAvailableWebPartDescriptions ();

override this.GetAvailableWebPartDescriptions : unit -> System.Web.UI.WebControls.WebParts.WebPartDescriptionCollection

Public Overrides Function GetAvailableWebPartDescriptions () As WebPartDescriptionCollection

Returns

WebPartDescriptionCollection

A WebPartDescriptionCollection that contains a WebPartDescription for each control in a catalog.

Examples

The following code example demonstrates how to use the GetAvailableWebPartDescriptions method on a Web page. The example has four parts:

A user control that enables you to change display modes on a Web Parts page.
A Web page that contains a CatalogZone control and an ImportCatalogPart control, along with code that uses the GetAvailableWebPartDescriptions method.
A source code file that contains two custom WebPart controls.
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. You should place the following source code in a file and name it Displaymodemenucs.ascx or Displaymodemenuvb.ascx (depending on which language you are using). 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>

<%@ 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="&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 Web page. At the top of the page are two register directives, one for the user control and one for the compiled component that contains the two custom WebPart controls. Both of these controls are referenced declaratively in the markup of the page. On the declarative references to the WebPart controls (both begin with an aspSample prefix), note that each has an exportMode="all" attribute added to it. This attribute enables you to export a .WebPart description file for the control, which you will use in a later to step to import the control to a page.

Note

To enable users of a Web Parts application to export a description file for WebPart controls, you must also enable the export feature in the Web application by adding an enableExport="true" attribute to the <webParts> element (which is a child of the <system.web> element) in the Web.config file. Export is disabled by default, so if you have not yet enabled export for your application, edit the Web.config file and do it now.

The Web page also has a declarative reference to the ImportCatalogPart control, nested within the proper hierarchy of declarative elements. The GetAvailableWebPartDescriptions method is called within the code for the Button1_Click method.

<%@ page language="c#" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuCS" 
  Src="DisplayModeMenuCS.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.CS.Controls" %>
  
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  // <snippet3>
  protected void Button1_Click(object sender, EventArgs e)
  {
    WebPartDescriptionCollection descriptions =
      ImportCatalogPart1.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();     

  }
  // </snippet3>

  // <snippet4>
  protected void Button2_Click(object sender, EventArgs e)
  {
    WebPartDescriptionCollection descriptions =
      ImportCatalogPart1.GetAvailableWebPartDescriptions();

    if (descriptions.Count > 0)
    {
      WebPart partToAdd =
        ImportCatalogPart1.GetWebPart(descriptions[0]);
      WebPartManager1.AddWebPart(partToAdd, zone1, 0);
    }
  }
  // </snippet4>
  
  protected void Page_Load(object sender, EventArgs e)
  {
    Button1.Visible = false;
    Button2.Visible = false;
    Label1.Visible = false;
  }

  protected void ImportCatalogPart1_PreRender(object sender, 
    EventArgs e)
  {
    Button1.Visible = true;
    Button2.Visible = true;
    Label1.Visible = true;
  }


</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>
      ImportCatalogPart 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:Calendar ID="Calendar1" runat="server" Title="My Calendar" />
          <aspsample:textdisplaywebpart id="wp1" runat="server" 
            Title="Text Display WebPart" exportmode="all" 
            description="Dynamically displays text in a label"/>
          <aspsample:userinfowebpart id="wp2" runat="server" 
            Title="User Info WebPart" exportmode="all" 
            description="Gathers user information" />
        </zonetemplate>
      </asp:webpartzone> 
      <asp:CatalogZone ID="CatalogZone1" runat="server">
        <ZoneTemplate>
          <asp:ImportCatalogPart ID="ImportCatalogPart1" 
            runat="server" 
            OnPreRender="ImportCatalogPart1_PreRender" />
        </ZoneTemplate>
      </asp:CatalogZone>
      <hr />
      <asp:Button ID="Button1" runat="server" 
        Text="Get WebPart Description" 
        OnClick="Button1_Click" />
      <br />
      <asp:Button ID="Button2" runat="server" 
        Text="Use GetWebPart" 
        OnClick="Button2_Click" />
      <asp:Label ID="Label1" runat="server" Text=""></asp:Label>  
    </form>
  </body>
</html>

<%@ page language="vb" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuVB" 
  Src="DisplayModeMenuVB.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.VB.Controls" %>
  
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

' <snippet3>
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim descriptions As WebPartDescriptionCollection = _
      ImportCatalogPart1.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("&nbsp;ID: " + _
        description.ID + "<br />")
      descriptionContent.AppendLine("&nbsp;Description: " + _
        description.Description + "<br /></div><hr />")
    Next description

    Label1.Text = "<h3>Catalog Contents</h3>" + descriptionContent.ToString()
End Sub
' </snippet3>

' <snippet4>
Protected Sub Button2_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim descriptions As WebPartDescriptionCollection = _
      ImportCatalogPart1.GetAvailableWebPartDescriptions
    If (descriptions.Count > 0) Then
        Dim partToAdd As WebPart = ImportCatalogPart1.GetWebPart(descriptions(0))
        WebPartManager1.AddWebPart(partToAdd, zone1, 0)
    End If
End Sub
' </snippet4>

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    Button1.Visible = false
    Button2.Visible = false
    Label1.Visible = false
End Sub

Protected Sub ImportCatalogPart1_PreRender(ByVal sender As Object, ByVal e As EventArgs)
    Button1.Visible = true
    Button2.Visible = true
    Label1.Visible = true
End Sub

</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>
      ImportCatalogPart 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:Calendar ID="Calendar1" runat="server" Title="My Calendar" />
          <aspsample:textdisplaywebpart id="wp1" runat="server" 
            Title="Text Display WebPart" exportmode="all" 
            description="Dynamically displays text in a label"/>
          <aspsample:userinfowebpart id="wp2" runat="server" 
            Title="User Info WebPart" exportmode="all" 
            description="Gathers user information" />
        </zonetemplate>
      </asp:webpartzone> 
      <asp:CatalogZone ID="CatalogZone1" runat="server">
        <ZoneTemplate>
          <asp:ImportCatalogPart ID="ImportCatalogPart1" 
            runat="server" 
            OnPreRender="ImportCatalogPart1_PreRender" />
        </ZoneTemplate>
      </asp:CatalogZone>
      <hr />
      <asp:Button ID="Button1" runat="server" 
        Text="Get WebPart Description" 
        OnClick="Button1_Click" />
      <br />
      <asp:Button ID="Button2" runat="server" 
        Text="Use GetWebPart" 
        OnClick="Button2_Click" />
      <asp:Label ID="Label1" runat="server" Text=""></asp:Label>  
    </form>
  </body>
</html>

The third part of the code example is the source code for the two 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. This code example uses dynamic compilation. 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 (!string.IsNullOrEmpty(input.Text))
      {
        _contentText = input.Text + @"<br />";
        input.Text = String.Empty;
        DisplayContent.Text = this.ContentText;
      }
    }
  }
}

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

Now run the code example. Load the Web page in a browser. The first step is export a .WebPart description file for each WebPart control (for the TextDisplayWebPart and for the UserInfoWebPart control). For each control, click the verbs menu on the control (represented by the downward arrow in the title bar), and click Export. Follow the instructions to save a .WebPart description file for the control. After you have exported a description file for each control, close the Web page, and edit the page source in an editor. Delete the <aspSample:userinfowebpart> and the <aspSample:textdisplaywebpart> control declaration elements, then save and close the file. (You are doing this step to simulate a user who does not yet have these controls, so you can import the controls to the page).

Load the Web page again in a browser. Use the Display Mode drop-down list control and select Catalog to switch the page to catalog mode. In the ImportCatalogPart control, click the Browse button, browse to the .WebPart files you created, select one, then click the Upload button. A reference to the control should appear with a check box next to it. Select the check box, then click Add to add the control to the page. Repeat this process for the other control.

While you are in this view of the page, click the Get WebPart Description button near the bottom of the page to see the effect of programmatically accessing the WebPartDescription object for the control description currently loaded in the ImportCatalogPart control. The method used to access the description details, found in the Button1_Click method of the page source, is the GetAvailableWebPartDescriptions method. A label below the button displays basic details about the control.

After adding the first control, repeat the process to add the second control to the page. Finally, click Close to exit catalog mode and return the page to browse mode. Both custom controls should now appear in the page, containing the values they had when you exported description files earlier.

Remarks

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. Note that in the case of an ImportCatalogPart control, there can be only one server control in the catalog at a time, even though the method would work if there were multiple controls.

A WebPartDescription object is an object that 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, and the call returns only the description information for the control rather than an instance of the control.

Applies to

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