ListView.ItemEditing Evento

Definição

Ocorre quando uma operação de edição é solicitada, mas antes que o item ListView seja colocado no modo de edição.Occurs when an edit operation is requested, but before the ListView item is put in edit mode.

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

Tipo de evento

EventHandler<ListViewEditEventArgs>

Exemplos

O exemplo a seguir mostra como adicionar um manipulador de eventos para o ItemEditing evento.The following example shows how to add an event handler for the ItemEditing event.

Importante

Este exemplo tem uma caixa de texto que aceita a entrada do usuário, que é uma possível ameaça à segurança.This example has a text box that accepts user input, which is a potential security threat. Por padrão, as páginas da Web do ASP.NET validam que a entrada do usuário não inclui elementos de script ou HTML.By default, ASP.NET Web pages validate that user input does not include script or HTML elements. Para obter mais informações, consulte Visão geral de explorações de script.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 ProductsListView_ItemEditing(Object sender, ListViewEditEventArgs e)
  {
    ListViewItem item = ProductsListView.Items[e.NewEditIndex];
    Label dateLabel = (Label)item.FindControl("DiscontinuedDateLabel");
    
    if (String.IsNullOrEmpty(dateLabel.Text))
      return;
    
    //Verify if the item is discontinued.
    DateTime discontinuedDate = DateTime.Parse(dateLabel.Text);
    if (discontinuedDate < DateTime.Now)
    {
      Message.Text = "You cannot edit a discontinued item.";
      e.Cancel = true;
      ProductsListView.SelectedIndex = -1;
    }       
  }
  //</Snippet2>

  void DiscontinuedDateCalendar_OnSelectionChanged(Object sender, EventArgs e)
  {
    TextBox dateTextBox = 
      (TextBox)ProductsListView.EditItem.FindControl("DiscontinuedDateTextBox");
    Calendar calendarObject = (Calendar)sender;
    dateTextBox.Text = calendarObject.SelectedDate.ToString("d");
  }

  DateTime GetDateTime(object dateValue)
  {
    if (dateValue == DBNull.Value)
      return DateTime.Now;
    else
      return (DateTime)dateValue;
  }

  protected void ProductsListView_PagePropertiesChanging(object sender, PagePropertiesChangingEventArgs e)
  {
    // Clears the edit index selection when paging.
    ProductsListView.EditIndex = -1;
  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView Edit Item Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView Edit Item Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>
     
      <asp:ListView ID="ProductsListView" 
        DataSourceID="ProductsDataSource" 
        DataKeyNames="ProductID"
        OnItemEditing="ProductsListView_ItemEditing" 
        ConvertEmptyStringToNull="true"        
        OnPagePropertiesChanging="ProductsListView_PagePropertiesChanging"
        runat="server" >
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblProducts" width="640px">
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ProductsDataPager" 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:LinkButton ID="EditButton" runat="server" Text="Edit" CommandName="Edit" />
            </td>
            <td valign="top">
              <asp:Label ID="NameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
            <td valign="top">
              <asp:Label ID="ProductNumberLabel" runat="server" Text='<%#Eval("ProductNumber") %>' />
            </td>
            <td>
              <asp:Label ID="DiscontinuedDateLabel" runat="server" 
                Text='<%#Eval("DiscontinuedDate", "{0:d}") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <EditItemTemplate>
          <tr style="background-color:#ADD8E6">
            <td valign="top">
              <asp:LinkButton ID="UpdateButton" runat="server" 
                CommandName="Update" Text="Update" /><br />
              <asp:LinkButton ID="CancelButton" runat="server" 
                CommandName="Cancel" Text="Cancel" />
            </td>
            <td valign="top" colspan="2">
              <asp:Label runat="server" ID="NameLabel" 
                AssociatedControlID="NameTextBox" 
                Text="Name"/>
              <asp:TextBox ID="NameTextBox" runat="server" 
                Text='<%#Bind("Name") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="ProductNumberLabel" 
                AssociatedControlID="ProductNumberTextBox" 
                Text="Product Number" />
              <asp:TextBox ID="ProductNumberTextBox" runat="server" 
                Text='<%#Bind("ProductNumber") %>' MaxLength="25" /><br />
            </td>
            <td>
              <asp:Label runat="server" ID="DiscontinuedDateLabel" 
                AssociatedControlID="DiscontinuedDateTextBox" 
                Text="Discontinued Date"/>
              <asp:TextBox ID="DiscontinuedDateTextBox" runat="server" 
                Text='<%# Bind("DiscontinuedDate", "{0:d}") %>'
                MaxLength="10" /><br />
              <asp:Calendar ID="DiscontinuedDateCalendar" runat="server" 
                SelectedDate='<%# GetDateTime(Eval("DiscontinuedDate")) %>'
                OnSelectionChanged="DiscontinuedDateCalendar_OnSelectionChanged" />
            </td>
          </tr>
        </EditItemTemplate>
      </asp:ListView>

      <!-- 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="ProductsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ProductID], [Name], [ProductNumber], [DiscontinuedDate] 
          FROM Production.Product"
        UpdateCommand="UPDATE Production.Product
          SET Name = @Name, ProductNumber = @ProductNumber, DiscontinuedDate = @DiscontinuedDate
          WHERE ProductID = @ProductID">
      </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 ProductsListView_ItemEditing(ByVal sender As Object, ByVal e As ListViewEditEventArgs)
    Dim item As ListViewItem = ProductsListView.Items(e.NewEditIndex)
    Dim dateLabel As Label = CType(item.FindControl("DiscontinuedDateLabel"), Label)
      
    If String.IsNullOrEmpty(dateLabel.Text) Then _
      Return
      
    'Verify if the item is discontinued.
    Dim discontinuedDate As DateTime = DateTime.Parse(dateLabel.Text)
    If discontinuedDate < DateTime.Now Then
      Message.Text = "You cannot edit a discontinued item."
      e.Cancel = True
      ProductsListView.SelectedIndex = -1
    End If
  End Sub
  '</Snippet2>
  
  Sub DiscontinuedDateCalendar_OnSelectionChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim dateTextBox As TextBox = _
      CType(ProductsListView.EditItem.FindControl("DiscontinuedDateTextBox"), TextBox)
    Dim calendarObject As Calendar = CType(sender, Calendar)
    dateTextBox.Text = calendarObject.SelectedDate.ToString("d")
  End Sub

  Function GetDateTime(ByVal dateValue As Object) As DateTime
    If dateValue Is DBNull.Value Then
      Return DateTime.Now
    Else
      Return CType(dateValue, DateTime)
    End If
  End Function
  
  Protected Sub ProductsListView_PagePropertiesChanging(ByVal sender As Object, _
                                               ByVal e As PagePropertiesChangingEventArgs)
    ' Clears the edit index selection when paging.
    ProductsListView.EditIndex = -1
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView Edit Item Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView Edit Item Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>
     
      <asp:ListView ID="ProductsListView" 
        DataSourceID="ProductsDataSource" 
        DataKeyNames="ProductID"
        OnItemEditing="ProductsListView_ItemEditing" 
        ConvertEmptyStringToNull="true"        
        OnPagePropertiesChanging="ProductsListView_PagePropertiesChanging"
        runat="server" >
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblProducts" width="640px">
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ProductsDataPager" 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:LinkButton ID="EditButton" runat="server" Text="Edit" CommandName="Edit" />
            </td>
            <td valign="top">
              <asp:Label ID="NameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
            <td valign="top">
              <asp:Label ID="ProductNumberLabel" runat="server" Text='<%#Eval("ProductNumber") %>' />
            </td>
            <td>
              <asp:Label ID="DiscontinuedDateLabel" runat="server" 
                Text='<%#Eval("DiscontinuedDate", "{0:d}") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <EditItemTemplate>
          <tr style="background-color:#ADD8E6">
            <td valign="top">
              <asp:LinkButton ID="UpdateButton" runat="server" 
                CommandName="Update" Text="Update" /><br />
              <asp:LinkButton ID="CancelButton" runat="server" 
                CommandName="Cancel" Text="Cancel" />
            </td>
            <td valign="top" colspan="2">
              <asp:Label runat="server" ID="NameLabel" 
                AssociatedControlID="NameTextBox" 
                Text="Name"/>
              <asp:TextBox ID="NameTextBox" runat="server" 
                Text='<%#Bind("Name") %>' MaxLength="50" /><br />
              <asp:Label runat="server" ID="ProductNumberLabel" 
                AssociatedControlID="ProductNumberTextBox" 
                Text="Product Number" />
              <asp:TextBox ID="ProductNumberTextBox" runat="server" 
                Text='<%#Bind("ProductNumber") %>' MaxLength="25" /><br />
            </td>
            <td>
              <asp:Label runat="server" ID="DiscontinuedDateLabel" 
                AssociatedControlID="DiscontinuedDateTextBox" 
                Text="Discontinued Date"/>
              <asp:TextBox ID="DiscontinuedDateTextBox" runat="server" 
                Text='<%# Bind("DiscontinuedDate", "{0:d}") %>'
                MaxLength="10" /><br />
              <asp:Calendar ID="DiscontinuedDateCalendar" runat="server" 
                SelectedDate='<%# GetDateTime(Eval("DiscontinuedDate")) %>'
                OnSelectionChanged="DiscontinuedDateCalendar_OnSelectionChanged" />
            </td>
          </tr>
        </EditItemTemplate>
      </asp:ListView>

      <!-- 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="ProductsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ProductID], [Name], [ProductNumber], [DiscontinuedDate] 
          FROM Production.Product"
        UpdateCommand="UPDATE Production.Product
          SET Name = @Name, ProductNumber = @ProductNumber, DiscontinuedDate = @DiscontinuedDate
          WHERE ProductID = @ProductID">
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

Comentários

O ItemEditing evento é gerado quando um botão de edição de um item é clicado, mas antes de o ListView Item ser colocado no modo de edição.The ItemEditing event is raised when an item's Edit button is clicked, but before the ListView item is put in edit mode. (Um botão de edição é um controle de botão cuja CommandName propriedade está definida como "Editar".) Isso permite que você execute uma rotina personalizada sempre que esse evento ocorrer, como cancelar a operação de edição.(An Edit button is a button control whose CommandName property is set to "Edit".) This enables you to perform a custom routine whenever this event occurs, such as canceling the edit operation.

Um ListViewEditEventArgs objeto é passado para o manipulador de eventos, que permite que você determine o índice do item atual.A ListViewEditEventArgs object is passed to the event handler, which enables you to determine the index of the current item. Ele também permite que você indique que a operação de edição deve ser cancelada.It also lets you indicate that the edit operation should be canceled. Para cancelar a operação de edição, defina a Cancel Propriedade do ListViewEditEventArgs objeto como true .To cancel the edit operation, set the Cancel property of the ListViewEditEventArgs object to true.

Para obter mais informações sobre como lidar com eventos, consulte manipulando e gerando eventos.For more information about how to handle events, see Handling and Raising Events.

Aplica-se a

Confira também