ListView.ItemInserting ListView.ItemInserting ListView.ItemInserting ListView.ItemInserting Event

Definition

Tritt ein, wenn ein Einfügevorgang angefordert wird, jedoch vor dem Ausführen des Einfügevorgangs durch das ListView-Steuerelement.Occurs when an insert operation is requested, but before the ListView control performs the insert.

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

Beispiele

Im folgenden Beispiel wird gezeigt, wie ein Ereignishandler für das ItemInserting -Ereignis hinzugefügt wird.The following example shows how to add an event handler for the ItemInserting event.

Wichtig

Dieses Beispiel enthält Steuerelemente, die Benutzereingaben akzeptieren, was eine potenzielle Sicherheitsbedrohung darstellt.This example contains controls that accept user input, which is a potential security threat. Standardmäßig stellen ASP.NET-Webseiten sicher, dass Benutzereingaben keine Skript- oder HTML-Elemente enthalten.By default, ASP.NET Web pages validate that user input does not include script or HTML elements. Weitere Informationen finden Sie unter Übersicht über Skriptangriffe.For more information, see Script Exploits Overview.

<%@ 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">
    
  void Page_Load()
  {
    Message.Text = String.Empty;
  }

  //<Snippet2>
  void ContactsListView_ItemInserting(Object sender, ListViewInsertEventArgs e)
  {
    // Iterate through the values to verify if they are not empty.
    foreach (DictionaryEntry de in e.Values)
    {
      if (de.Value == null)
      {
        Message.Text = "Cannot insert an empty value.";
        e.Cancel = true;
      }
    }
  }
  //</Snippet2>

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView.ItemInserting Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView.ItemInserting Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>
     
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemInserting="ContactsListView_ItemInserting"  
        InsertItemPosition="LastItem"
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" border="1" runat="server" id="tblProducts" width="640px">
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|&lt;&lt; " LastPageText=" &gt;&gt;|"
                NextPageText=" &gt; " PreviousPageText=" &lt; " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
              &nbsp;
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
              &nbsp;
            </td>
          </tr>
        </ItemTemplate>
        <InsertItemTemplate>
          <tr style="background-color:#B0C4DE">
            <td valign="top">
              <asp:Label runat="server" ID="FirstNameLabel" 
                AssociatedControlID="FirstNameTextBox" Text="First Name"/>
              <asp:TextBox ID="FirstNameTextBox" runat="server" 
                Text='<%#Bind("FirstName") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="LastNameLabel" 
                AssociatedControlID="LastNameTextBox" Text="Last Name" />
              <asp:TextBox ID="LastNameTextBox" runat="server" 
                Text='<%#Bind("LastName") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="EmailLabel" 
                AssociatedControlID="EmailTextBox" Text="Email" />
              <asp:TextBox ID="EmailTextBox" runat="server" 
                Text='<%#Bind("EmailAddress") %>' MaxLength="50" /><br />
            </td>
            <td>
              <asp:LinkButton ID="InsertButton" runat="server" CommandName="Insert" Text="Insert" />
            </td>
          </tr>
        </InsertItemTemplate>
      </asp:ListView>
            
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] 
          FROM Person.Contact"
        InsertCommand="INSERT INTO Person.Contact
                       ([FirstName], [LastName], [EmailAddress], [PasswordHash], [PasswordSalt]) 
                       Values(@FirstName, @LastName, @EmailAddress, '', '');
                       SELECT @ContactID = SCOPE_IDENTITY()">
        <InsertParameters>
          <asp:Parameter Name="FirstName" />
          <asp:Parameter Name="LastName" />
          <asp:Parameter Name="EmailAddress" />
          <asp:Parameter Name="ContactID" Type="Int32" Direction="Output" />
        </InsertParameters>
      </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">

  Sub Page_Load()
    Message.Text = String.Empty
  End Sub

  '<Snippet2>
  Sub ContactsListView_ItemInserting(ByVal sender As Object, _
                                     ByVal e As ListViewInsertEventArgs)
  
    ' Iterate through the values to verify if they are not empty.
    For Each de As DictionaryEntry In e.Values
      If de.Value Is Nothing Then
        Message.Text = "Cannot insert an empty value."
        e.Cancel = True
      End If
    Next
  End Sub
  '</Snippet2>

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView.ItemInserting Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView.ItemInserting Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>
     
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemInserting="ContactsListView_ItemInserting"  
        InsertItemPosition="LastItem"
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" border="1" runat="server" id="tblProducts" width="640px">
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|&lt;&lt; " LastPageText=" &gt;&gt;|"
                NextPageText=" &gt; " PreviousPageText=" &lt; " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
              &nbsp;
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
              &nbsp;
            </td>
          </tr>
        </ItemTemplate>
        <InsertItemTemplate>
          <tr style="background-color:#B0C4DE">
            <td valign="top">
              <asp:Label runat="server" ID="FirstNameLabel" 
                AssociatedControlID="FirstNameTextBox" Text="First Name"/>
              <asp:TextBox ID="FirstNameTextBox" runat="server" 
                Text='<%#Bind("FirstName") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="LastNameLabel" 
                AssociatedControlID="LastNameTextBox" Text="Last Name" />
              <asp:TextBox ID="LastNameTextBox" runat="server" 
                Text='<%#Bind("LastName") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="EmailLabel" 
                AssociatedControlID="EmailTextBox" Text="Email" />
              <asp:TextBox ID="EmailTextBox" runat="server" 
                Text='<%#Bind("EmailAddress") %>' MaxLength="50" /><br />
            </td>
            <td>
              <asp:LinkButton ID="InsertButton" runat="server" CommandName="Insert" Text="Insert" />
            </td>
          </tr>
        </InsertItemTemplate>
      </asp:ListView>
            
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] 
          FROM Person.Contact"
        InsertCommand="INSERT INTO Person.Contact
                       ([FirstName], [LastName], [EmailAddress], [PasswordHash], [PasswordSalt]) 
                       Values(@FirstName, @LastName, @EmailAddress, '', '');
                       SELECT @ContactID = SCOPE_IDENTITY()">
        <InsertParameters>
          <asp:Parameter Name="FirstName" />
          <asp:Parameter Name="LastName" />
          <asp:Parameter Name="EmailAddress" />
          <asp:Parameter Name="ContactID" Type="Int32" Direction="Output" />
        </InsertParameters>
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

Hinweise

Das ListView -Steuerelement ItemInserting löst das-Ereignis aus, wenn InsertItemTemplate auf eine INSERT-Schalt InsertNewItem Fläche in der Vorlage geklickt wird oder ListView die-Methode aufgerufen wird, bevor das-Steuerelement den Datensatz einfügt.The ListView control raises the ItemInserting event when an Insert button in the InsertItemTemplate template is clicked or the InsertNewItem method is called, but before the ListView control inserts the record. (Eine Schaltfläche Einfügen ist ein Schaltflächen CommandName -Steuerelement, dessen-Eigenschaft auf "Insert" festgelegt ist.) Dies ermöglicht es Ihnen, bei jedem Auftreten dieses Ereignisses eine benutzerdefinierte Routine auszuführen, z. b. die HTML-Codierung der Werte eines Datensatzes, bevor dieser in die Datenquelle eingefügt wird.(An Insert button is a button control whose CommandName property is set to "Insert".) This enables you to perform a custom routine whenever this event occurs, such as HTML-encoding the values of a record before it is inserted in the data source.

Ein ListViewInsertEventArgs -Objekt wird an den-Ereignishandler übermittelt, mit dem Sie den Wert eines optionalen Befehls Arguments bestimmen können, ListView das an das-Steuerelement gesendet wird.A ListViewInsertEventArgs object is passed to the event handler, which enables you to determine the value of an optional command argument sent to the ListView control. Außerdem können Sie angeben, dass der Einfügevorgang abgebrochen werden soll.It also lets you indicate that the insert operation should be canceled. Legen Sie die Cancel -Eigenschaft auf truefest, um den INSERT-Vorgang abzubrechen.To cancel the insert operation, set the Cancel property to true. Sie können die Feldwerte für den neuen Datensatz lesen oder ändern, indem Sie Values die-Eigenschaft verwenden.You can read or modify the field values for the new record by using the Values property.

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