ListView.PagePropertiesChanging ListView.PagePropertiesChanging ListView.PagePropertiesChanging ListView.PagePropertiesChanging Event

Definition

Tritt ein, wenn die Seiteneigenschaften geändert werden, jedoch bevor das ListView-Steuerelement die neuen Werte festlegt.Occurs when the page properties change, but before the ListView control sets the new values.

public:
 event EventHandler<System::Web::UI::WebControls::PagePropertiesChangingEventArgs ^> ^ PagePropertiesChanging;
public event EventHandler<System.Web.UI.WebControls.PagePropertiesChangingEventArgs> PagePropertiesChanging;
member this.PagePropertiesChanging : EventHandler<System.Web.UI.WebControls.PagePropertiesChangingEventArgs> 
Public Custom Event PagePropertiesChanging As EventHandler(Of PagePropertiesChangingEventArgs) 

Beispiele

Im folgenden Beispiel wird gezeigt, wie ein Ereignishandler für PagePropertiesChanging das-Ereignis erstellt wird.The following example shows how create an event handler for the PagePropertiesChanging event.

<%@ Page language="C#" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
  
  // <Snippet2>
  protected void DeleteButton_Click(object sender, EventArgs e)
  {
    //Check if an item is selected to delete it.
    if (ContactsListView.SelectedIndex >= 0)
      ContactsListView.DeleteItem(ContactsListView.SelectedIndex);
    else
      Message.Text = "No contact was selected.";
  }
  // </Snippet2>

  protected void ContactsListView_ItemDeleted(object sender, ListViewDeletedEventArgs e)
  {
    //Check if an exception occurred to display an error message.
    if (e.Exception != null)
    {
      Message.Text = "An exception occurred deleting the contact.";
      e.ExceptionHandled = true;
    }
    else
    {
      // Clear the selected index.
      ContactsListView.SelectedIndex = -1;
    }
  }

  protected void ContactsListView_PagePropertiesChanging(object sender, 
    PagePropertiesChangingEventArgs e)
  {
    //Clear the selected index.
    ContactsListView.SelectedIndex = -1;
  }

  protected void Page_Load(object sender, EventArgs e)
  {
    //Clear the message label.
    Message.Text = "";
  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView DeleteItem Example</title>
    <style type="text/css">
      body
      {
        font-size: 10pt;
        font-family: Trebuchet MS, Arial, Tahoma;
        text-align:center;
      }
      .item { background-color: #E0FFFF }
      .selectedItem { background-color: #B0E0E6 }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView DeleteItem Example</h3>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource"
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"
        OnPagePropertiesChanging="ContactsListView_PagePropertiesChanging"
        runat="server" >
        <LayoutTemplate>
          <table cellpadding="2" width="640px" id="tblProducts" runat="server">
            <tr runat="server">
              <th runat="server">&nbsp;</th>
              <th runat="server">ID</th>
              <th runat="server">Account Number</th>
              <th runat="server">LastName</th>
              <th runat="server">Preferred Vendor</th>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager ID="ContactsDataPager" runat="server" PageSize="15">
            <Fields>
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowFirstPageButton="true"
                ShowNextPageButton="false"
                ShowPreviousPageButton="false" />
              <asp:NumericPagerField ButtonCount="10" />
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowLastPageButton="true"
                ShowNextPageButton="false"
                ShowPreviousPageButton="false" />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr class="item" runat="server">
            <td>
              <asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
            </td>
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <SelectedItemTemplate>
          <tr class="selectedItem" runat="server">
            <td>&nbsp;</td>
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
            </td>
          </tr>
        </SelectedItemTemplate>
      </asp:ListView>
      <br />
      <br />
           
      <asp:Button ID="DeleteButton"       
        Text="Delete Selected Contact"
        OnClick="DeleteButton_Click"
        runat="server" />
      <br />

      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>

      <!-- This example uses Microsoft SQL Server and connects      -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET    -->
      <!-- expression to retrieve the connection string value       -->
      <!-- from the Web.config file.                                -->
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"            
        SelectCommand="SELECT ContactID, FirstName, LastName, EmailAddress 
          FROM Person.Contact" 
        DeleteCommand="DELETE FROM Person.Contact WHERE (ContactID = @ContactID)" >
      </asp:SqlDataSource>      
    </form>
  </body>
</html>
<%@ Page language="VB" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
  
  ' <Snippet2>
  Protected Sub DeleteButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    
    ' Check if an item is selected to delete it.
    If ContactsListView.SelectedIndex >= 0 Then
      ContactsListView.DeleteItem(ContactsListView.SelectedIndex)
    Else
      Message.Text = "No contact was selected."
    End If
    
  End Sub
  ' </Snippet2>
    
  Protected Sub ContactsListView_ItemDeleted(ByVal sender As Object, _
    ByVal e As ListViewDeletedEventArgs)
    
    ' Check if an exception occurred to display an error message.
    If Not (e.Exception Is Nothing) Then
      Message.Text = "An exception occurred deleting the contact."
      e.ExceptionHandled = True
    Else
      ' Clear the selected index.
      ContactsListView.SelectedIndex = -1
    End If
    
  End Sub

  Protected Sub ContactsListView_PagePropertiesChanging(ByVal sender As Object, _
    ByVal e As PagePropertiesChangingEventArgs)
    
    ' Clear the selected index.
    ContactsListView.SelectedIndex = -1
    
  End Sub

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    ' Clear the message label.
    Message.Text = ""
  End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView DeleteItem Example</title>
    <style type="text/css">
      body
      {
        font-size: 10pt;
        font-family: Trebuchet MS, Arial, Tahoma;
        text-align:center;
      }
      .item { background-color: #E0FFFF }
      .selectedItem { background-color: #B0E0E6 }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView DeleteItem Example</h3>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource"
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"
        OnPagePropertiesChanging="ContactsListView_PagePropertiesChanging"
        runat="server" >
        <LayoutTemplate>
          <table cellpadding="2" width="640px" id="tblProducts" runat="server">
            <tr runat="server">
              <th runat="server">&nbsp;</th>
              <th runat="server">ID</th>
              <th runat="server">Account Number</th>
              <th runat="server">LastName</th>
              <th runat="server">Preferred Vendor</th>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager ID="ContactsDataPager" runat="server" PageSize="15">
            <Fields>
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowFirstPageButton="true"
                ShowNextPageButton="false"
                ShowPreviousPageButton="false" />
              <asp:NumericPagerField ButtonCount="10" />
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowLastPageButton="true"
                ShowNextPageButton="false"
                ShowPreviousPageButton="false" />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr class="item" runat="server">
            <td>
              <asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
            </td>
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <SelectedItemTemplate>
          <tr class="selectedItem" runat="server">
            <td>&nbsp;</td>
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
            </td>
          </tr>
        </SelectedItemTemplate>
      </asp:ListView>
      <br />
      <br />
           
      <asp:Button ID="DeleteButton"       
        Text="Delete Selected Contact"
        OnClick="DeleteButton_Click"
        runat="server" />
      <br />

      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>

      <!-- This example uses Microsoft SQL Server and connects      -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET    -->
      <!-- expression to retrieve the connection string value       -->
      <!-- from the Web.config file.                                -->
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"            
        SelectCommand="SELECT ContactID, FirstName, LastName, EmailAddress 
          FROM Person.Contact" 
        DeleteCommand="DELETE FROM Person.Contact WHERE (ContactID = @ContactID)" >
      </asp:SqlDataSource>      
    </form>
  </body>
</html>

Hinweise

Das PagePropertiesChanging -Ereignis wird ausgelöst, wenn die Seiteneigenschaften geändert werden, ListView aber bevor das-Steuerelement die neuen SetPageProperties Werte mithilfe der-Methode festlegt.The PagePropertiesChanging event is raised when the page properties change, but before the ListView control sets the new values by using the SetPageProperties method. Dies ermöglicht es Ihnen, bei jedem Auftreten dieses Ereignisses eine benutzerdefinierte Routine auszuführen, z SelectedIndex . EditIndex b. das Löschen der-oder-Eigenschaften.This enables you to perform a custom routine whenever this event occurs, such as clearing the SelectedIndex or EditIndex properties.

Ein PagePropertiesChangingEventArgs -Objekt wird an den-Ereignishandler weitergegeben, sodass Sie den Index des ersten auf der Seite angezeigten Datensatzes ermitteln können.A PagePropertiesChangingEventArgs object is passed to the event handler, which enables you to determine the index of the first record displayed on the page. Außerdem können Sie die maximale Anzahl von Elementen ermitteln, die auf einer einzelnen Seite angezeigt werden sollen.It also lets you determine the maximum number of items to display on a single page.

Weitere Informationen zum Behandeln von Ereignissen finden Sie unter behandeln und Auslösen von Ereignissen.For more information about how to handle events, see Handling and Raising Events.

Gilt für:

Siehe auch