ListView.DeleteItem(Int32) ListView.DeleteItem(Int32) ListView.DeleteItem(Int32) ListView.DeleteItem(Int32) Method

Definizione

Elimina dall'origine dati il record in corrispondenza dell'indice specificato.Deletes the record at the specified index from the data source.

public:
 virtual void DeleteItem(int itemIndex);
public virtual void DeleteItem (int itemIndex);
abstract member DeleteItem : int -> unit
override this.DeleteItem : int -> unit
Public Overridable Sub DeleteItem (itemIndex As Integer)

Parametri

itemIndex
Int32 Int32 Int32 Int32

Indice dell'elemento da eliminare.The index of the item to delete.

Eccezioni

itemIndex è minore di 0.itemIndex is less than 0.

In alternativa-or- L'oggetto DataSourceView associato al controllo ListView è null.The DataSourceView object that is associated with the ListView control is null.

Esempi

Nell'esempio seguente viene illustrato come utilizzare il DeleteItem metodo per eliminare a livello di codice l'elemento selezionato ListView in un controllo dall'origine dati.The following example shows how to use the DeleteItem method to programmatically delete the selected item in a ListView control from the data source.

<%@ 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>

Commenti

Utilizzare il DeleteItem metodo per eliminare a livello di codice il record in corrispondenza dell'indice specificato dall'origine dati.Use the DeleteItem method to programmatically delete the record at the specified index from the data source. Questo metodo viene in genere usato per eliminare un record dall'esterno ListView del controllo, ad esempio da un controllo diverso nella pagina.This method is typically used to delete a record from outside the ListView control, such as from a different control on the page. Questo metodo genera gli ItemDeleted eventi ItemDeleting e.This method raises the ItemDeleted and ItemDeleting events.

Si applica a

Vedi anche