ListView.ItemEditing Evento
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Si verifica quando viene richiesta un'operazione di modifica, ma prima che l'elemento ListView venga impostato sulla modalità di modifica.
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 evento
Esempio
Nell'esempio seguente viene illustrato come aggiungere un gestore eventi per l'evento ItemEditing .
Importante
L'esempio include una casella di testo che accetta l'input dell'utente e rappresenta quindi una potenziale minaccia alla sicurezza. Per impostazione predefinita, le pagine Web ASP.NET verificano che l'input dell'utente non includa script o elementi HTML. Per altre informazioni, vedere Cenni preliminari sugli attacchi tramite script.
<%@ 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="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</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="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</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>
Commenti
L'evento ItemEditing viene generato quando viene fatto clic sul pulsante Modifica di un elemento, ma prima che l'elemento ListView venga inserito in modalità di modifica. Un pulsante Modifica è un controllo pulsante la cui CommandName proprietà è impostata su "Modifica". Ciò consente di eseguire una routine personalizzata ogni volta che si verifica questo evento, ad esempio annullando l'operazione di modifica.
Un ListViewEditEventArgs oggetto viene passato al gestore eventi, che consente di determinare l'indice dell'elemento corrente. Consente inoltre di indicare che l'operazione di modifica deve essere annullata. Per annullare l'operazione di modifica, impostare la Cancel proprietà dell'oggetto ListViewEditEventArgs su true.
Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.
Si applica a
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