WebPartZoneBase.HelpVerb Vlastnost

public:
 virtual property System::Web::UI::WebControls::WebParts::WebPartVerb ^ HelpVerb { System::Web::UI::WebControls::WebParts::WebPartVerb ^ get(); };

[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public virtual System.Web.UI.WebControls.WebParts.WebPartVerb HelpVerb { get; }

[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.HelpVerb : System.Web.UI.WebControls.WebParts.WebPartVerb

Public Overridable ReadOnly Property HelpVerb As WebPartVerb

Hodnota vlastnosti

A WebPartVerb , který uživatelům umožňuje přístup k obsahu nápovědy ovládacích WebPart prvků v zóně.

Atributy

PersistenceModeAttribute

Příklady

Následující příklad kódu ukazuje použití HelpVerb vlastnosti v ovládacím prvku WebPartZone .

Aby příklad kódu fungoval, potřebujete kromě následujícího kódu také vlastní WebPart ovládací prvek. Můžete buď použít vlastní ovládací prvek, nebo použít kód pro vlastní TextDisplayWebPart ovládací prvek, který najdete v části Příklad v přehledu WebPart třídy.

Tento příklad kódu obsahuje uživatelský ovládací prvek, který umožňuje měnit režimy zobrazení na webové stránce. Další informace o režimech zobrazení a zdrojovém kódu v tomto ovládacím prvku najdete v tématu Návod: Změna režimů zobrazení na stránce webových částí.

<%@ 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=" 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=" 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>

Tento příklad kódu obsahuje také stránku HTML, která může obsahovat obsah nápovědy pro ovládací TextDisplayWebPart prvek. Aby tento příklad fungoval, musíte následující kód uložit do souboru s názvem Textwebparthelp.htm a umístit ho do stejného adresáře webu jako .aspx stránka, která je hostitelem TextDisplayWebPart ovládacího prvku.

<html>  
<head runat="server">  
    <title>Text Content WebPart Help</title>  
</head>  
<body>  
  <div>  
  <h1>Text Content WebPart Help</h1>  
  To make the WebPart control work...  
  </div>  
</body>  
</html>  

Příklad kódu obsahuje také následující částečnou třídu, která obsahuje kód pro zpracování událostí na stránce .aspx.

using System;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

public partial class WebPartZoneBase_verbs : System.Web.UI.Page
{
  protected void Page_Load(Object sender, EventArgs e)
  {
    if (WebPartZone1.WebParts.Count == 0)
      Table1.Visible = false;
    else
      Table1.Visible = true;

    // Enable all verbs on the first page load.
    if (!IsPostBack)
    {
      foreach (ListItem item in CheckBoxList1.Items)
        item.Selected = true;
      CheckBoxList1_SelectedItemIndexChanged(sender, e);
    } 
  }

  protected void CheckBoxList1_SelectedItemIndexChanged(Object sender, EventArgs e)
  {
    foreach (ListItem item in CheckBoxList1.Items)
    {
      WebPartVerb theVerb;
      switch (item.Value)
      {
        case "close":
          theVerb = WebPartZone1.CloseVerb;
          break;
        case "export":
          theVerb = WebPartZone1.ExportVerb;
          break;
        case "delete":
          theVerb = WebPartZone1.DeleteVerb;
          break;
        case "minimize":
          theVerb = WebPartZone1.MinimizeVerb;
          break;
        case "restore":
          theVerb = WebPartZone1.RestoreVerb;
          break;
        default:
          theVerb = null;
          break;
      }

      if (item.Selected)
        theVerb.Enabled = true;
      else
        theVerb.Enabled = false;
    }
  }
}

Imports System.Text
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts

Public Partial Class WebPartZoneBase_verbs

  Inherits System.Web.UI.Page

  Protected Sub Page_Load(ByVal sender As [Object], ByVal e As EventArgs)
    If WebPartZone1.WebParts.Count = 0 Then
      Table1.Visible = False
    Else
      Table1.Visible = True
    End If

    ' Enable all verbs on the first page load.
    If Not IsPostBack Then
      Dim item As ListItem
      For Each item In CheckBoxList1.Items
        item.Selected = True
      Next item
      CheckBoxList1_SelectedItemIndexChanged(sender, e)
    End If
  End Sub
    
  Protected Sub CheckBoxList1_SelectedItemIndexChanged(ByVal sender As [Object], ByVal e As EventArgs)
    Dim item As ListItem
    For Each item In CheckBoxList1.Items
      Dim theVerb As WebPartVerb
      Select Case item.Value
        Case "close"
          theVerb = WebPartZone1.CloseVerb
        Case "export"
          theVerb = WebPartZone1.ExportVerb
        Case "delete"
          theVerb = WebPartZone1.DeleteVerb
        Case "minimize"
          theVerb = WebPartZone1.MinimizeVerb
        Case "restore"
          theVerb = WebPartZone1.RestoreVerb
        Case Else
          theVerb = Nothing
      End Select

      If item.Selected Then
        theVerb.Enabled = True
      Else
        theVerb.Enabled = False
      End If
    Next item

  End Sub

End Class

Druhou částí příkladu kódu je stránka .aspx, která je hostitelem TextDisplayWebPart ovládacího prvku a ukazuje použití HelpVerb vlastnosti. Všimněte si, že v horní části stránky se používá deklarace, <@ Register %> která odkazuje na zkompilovaný TextDisplayWebPart ovládací prvek, který by měl být umístěn do podsložky s názvem Bin.

<%@ Page Language="C#" 
  Codefile="webpartzonebase_verbs.cs"
  Inherits="WebPartZoneBase_verbs"  %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuCS" 
  Src="DisplayModeMenuCS.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.CS.Controls" 
  Assembly="TextDisplayWebPartCS" %>

<!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" >
<head runat="server">
    <title>WebPartZoneBase Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <asp:WebPartManager ID="WebPartManager1" Runat="server" />
      <uc1:DisplayModeMenuCS ID="DisplayModeMenu1" runat="server" />
      <asp:WebPartZone ID="WebPartZone1" Runat="server">
        <CloseVerb Text="Close WebPart" />
        <HelpVerb Text="View Help" />
        <ExportVerb Text="Export WebPart Definition" />
        <DeleteVerb Text ="Delete WebPart" />
        <MinimizeVerb Description="Minimize the control" />
        <RestoreVerb Description="Restore the control" />
        <ZoneTemplate>
        </ZoneTemplate>  
      </asp:WebPartZone>
      <asp:CatalogZone ID="CatalogZone1" Runat="server">
        <ZoneTemplate>
          <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1" 
            Runat="server">
            <WebPartsTemplate>
              <aspSample:TextDisplayWebPart 
                runat="server"   
                id="textwebpart" 
                title = "Text Content WebPart" 
                width="350px" 
                AllowClose="true"
                ExportMode="All"
                HelpMode="Modal"
                HelpUrl="TextWebPartHelp.htm" />            
            </WebPartsTemplate>
          </asp:DeclarativeCatalogPart> 
          <asp:PageCatalogPart ID="PageCatalogPart1" Runat="server" />
        </ZoneTemplate>
      </asp:CatalogZone>
      <asp:Table ID="Table1" Runat="server">
        <asp:TableRow>
          <asp:TableCell>
            <asp:CheckBoxList ID="CheckBoxList1" Runat="server" 
              AutoPostBack="true" 
              OnSelectedIndexChanged="CheckBoxList1_SelectedItemIndexChanged">
              <asp:ListItem Value="close">Close Verb Enabled</asp:ListItem>
              <asp:ListItem Value="delete">Delete Verb Enabled</asp:ListItem>
              <asp:ListItem Value="export">Export Verb Enabled</asp:ListItem>
              <asp:ListItem Value="minimize">Minimize Verb Enabled</asp:ListItem>
              <asp:ListItem Value="restore">Restore Verb Enabled</asp:ListItem>
            </asp:CheckBoxList>
          </asp:TableCell>
        </asp:TableRow>
      </asp:Table>
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" 
  Codefile="webpartzonebase_verbs.vb"
  Inherits="WebPartZoneBase_verbs"  %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuVB" 
  Src="DisplayModeMenuVB.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.VB.Controls" 
  Assembly="TextDisplayWebPartVB" %>

<!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" >
<head runat="server">
    <title>WebPartZoneBase Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <asp:WebPartManager ID="WebPartManager1" Runat="server" />
      <uc1:DisplayModeMenuVB ID="DisplayModeMenu1" runat="server" />
      <asp:WebPartZone ID="WebPartZone1" Runat="server">
        <CloseVerb Text="Close WebPart" />
        <HelpVerb Text="View Help" />
        <ExportVerb Text="Export WebPart Definition" />
        <DeleteVerb Text ="Delete WebPart" />
        <MinimizeVerb Description="Minimize the control" />
        <RestoreVerb Description="Restore the control" />
        <ZoneTemplate>
        </ZoneTemplate>  
      </asp:WebPartZone>
      <asp:CatalogZone ID="CatalogZone1" Runat="server">
        <ZoneTemplate>
          <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1" 
            Runat="server">
            <WebPartsTemplate>
              <aspSample:TextDisplayWebPart 
                runat="server"   
                id="textwebpart" 
                title = "Text Content WebPart" 
                width="350px" 
                AllowClose="true"
                ExportMode="All"
                HelpMode="Modal"
                HelpUrl="TextWebPartHelp.htm" />            
            </WebPartsTemplate>
          </asp:DeclarativeCatalogPart> 
          <asp:PageCatalogPart ID="PageCatalogPart1" Runat="server" />
        </ZoneTemplate>
      </asp:CatalogZone>
      <asp:Table ID="Table1" Runat="server">
        <asp:TableRow>
          <asp:TableCell>
            <asp:CheckBoxList ID="CheckBoxList1" Runat="server" 
              AutoPostBack="true" 
              OnSelectedIndexChanged="CheckBoxList1_SelectedItemIndexChanged">
              <asp:ListItem Value="close">Close Verb Enabled</asp:ListItem>
              <asp:ListItem Value="delete">Delete Verb Enabled</asp:ListItem>
              <asp:ListItem Value="export">Export Verb Enabled</asp:ListItem>
              <asp:ListItem Value="minimize">Minimize Verb Enabled</asp:ListItem>
              <asp:ListItem Value="restore">Restore Verb Enabled</asp:ListItem>
            </asp:CheckBoxList>
          </asp:TableCell>
        </asp:TableRow>
      </asp:Table>
    </div>
    </form>
</body>
</html>

Všimněte si také, že HelpVerb vlastnost se používá deklarativně u elementu <asp:WebPartZone> k nastavení textu pro sloveso, jak je znázorněno v následujícím příkladu kódu.

<asp:WebPartZone ID="WebPartZone1" Runat="server">
  <CloseVerb Text="Close WebPart" />
  <HelpVerb Text="View Help" />
  <ExportVerb Text="Export WebPart Definition" />
  <DeleteVerb Text ="Delete WebPart" />
  <MinimizeVerb Description="Minimize the control" />
  <RestoreVerb Description="Restore the control" />
  <ZoneTemplate>
  </ZoneTemplate>  
</asp:WebPartZone>

<asp:WebPartZone ID="WebPartZone1" Runat="server">
  <CloseVerb Text="Close WebPart" />
  <HelpVerb Text="View Help" />
  <ExportVerb Text="Export WebPart Definition" />
  <DeleteVerb Text ="Delete WebPart" />
  <MinimizeVerb Description="Minimize the control" />
  <RestoreVerb Description="Restore the control" />
  <ZoneTemplate>
  </ZoneTemplate>  
</asp:WebPartZone>

Nakonec si v následujícím příkladu kódu všimněte, že HelpUrl vlastnost je nastavena u elementu <aspSample:TextDisplayPart> , který poskytuje adresu URL souboru nápovědy.

<asp:CatalogZone ID="CatalogZone1" Runat="server">
  <ZoneTemplate>
    <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1" 
      Runat="server">
      <WebPartsTemplate>
        <aspSample:TextDisplayWebPart 
          runat="server"   
          id="textwebpart" 
          title = "Text Content WebPart" 
          width="350px" 
          AllowClose="true"
          ExportMode="All"
          HelpMode="Modal"
          HelpUrl="TextWebPartHelp.htm" />            
      </WebPartsTemplate>
    </asp:DeclarativeCatalogPart> 
    <asp:PageCatalogPart ID="PageCatalogPart1" Runat="server" />
  </ZoneTemplate>
</asp:CatalogZone>

<asp:CatalogZone ID="CatalogZone1" Runat="server">
  <ZoneTemplate>
    <asp:DeclarativeCatalogPart ID="DeclarativeCatalogPart1" 
      Runat="server">
      <WebPartsTemplate>
        <aspSample:TextDisplayWebPart 
          runat="server"   
          id="textwebpart" 
          title = "Text Content WebPart" 
          width="350px" 
          AllowClose="true"
          ExportMode="All"
          HelpMode="Modal"
          HelpUrl="TextWebPartHelp.htm" />            
      </WebPartsTemplate>
    </asp:DeclarativeCatalogPart> 
    <asp:PageCatalogPart ID="PageCatalogPart1" Runat="server" />
  </ZoneTemplate>
</asp:CatalogZone>

Po načtení stránky v prohlížeči kliknutím na položku nabídky Režim katalogu v ovládacím prvku rozevíracího seznamu Režim zobrazení přepněte stránku do režimu zobrazení katalogu. TextDisplayWebPart Přidejte ovládací prvek na stránku, zavřete katalog a vraťte stránku do normálního režimu procházení. Pokud kliknete na rozevírací nabídku sloves v záhlaví TextDisplayWebPart ovládacího prvku, můžete otevřít stránku nápovědy.

Poznámky

Vlastnost HelpVerb je přístupná buď deklarativním způsobem, nebo programově. Můžete k němu přistupovat deklarativně v rámci zóny pomocí elementu <asp:HelpVerb> k nastavení textu, popisu, zda je příkaz povolen a dalších atributů. Není však nutné deklarovat příkaz nápovědy pro zónu, protože je ve výchozím nastavení povolen. Jediným krokem, který je nutný k tomu, aby se příkaz nápovědy zobrazil v nabídce sloves ovládacích WebPart prvků v zóně za běhu, je přiřazení hodnoty HelpUrl vlastnosti pro jednotlivé WebPart ovládací prvky.

Platí pro

Viz také

• HelpUrl
• Návod: Změna režimů zobrazení na stránce webových částí
• ASP.NET ovládací prvky webových částí