ListView.SelectedIndexChanged Evento
Definizione
Importante
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Si verifica quando viene fatto clic sul pulsante Select di un elemento, ma dopo che il controllo ListView ha gestito l'operazione di selezione.
public:
event EventHandler ^ SelectedIndexChanged;public event EventHandler SelectedIndexChanged;member this.SelectedIndexChanged : EventHandler Public Custom Event SelectedIndexChanged As EventHandler Tipo evento
Esempio
Nell'esempio seguente viene illustrato come creare un gestore eventi per l'evento SelectedIndexChanged .
<%@ 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">
//<Snippet3>
void ContactsListView_SelectedIndexChanged(Object sender, EventArgs e)
{
if (ContactsListView.SelectedIndex >= 0)
ViewState["SelectedKey"] = ContactsListView.SelectedValue;
else
ViewState["SelectedKey"] = null;
}
void ContactsListView_DataBound(Object sender, EventArgs e)
{
for (int i = 0; i < ContactsListView.Items.Count; i++)
{
// Ignore values that cannot be cast as integer.
try
{
if ((int)ContactsListView.DataKeys[i].Value == (int)ViewState["SelectedKey"])
ContactsListView.SelectedIndex = i;
}
catch { }
}
}
//</Snippet3>
void ContactsListView_PagePropertiesChanged(Object sender, EventArgs e)
{
ContactsListView.SelectedIndex = -1;
}
void ContactsListView_Sorting(Object sender, ListViewSortEventArgs e)
{
ContactsListView.SelectedIndex = -1;
}
void ClearButton_Click(Object sender, EventArgs e)
{
ViewState["SelectedKey"] = null;
ContactsListView.SelectedIndex = -1;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView SelectedIndex Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView SelectedIndex Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
DataKeyNames="ContactID"
OnDataBound="ContactsListView_DataBound"
OnSelectedIndexChanged="ContactsListView_SelectedIndexChanged"
OnPagePropertiesChanged="ContactsListView_PagePropertiesChanged"
OnSorting="ContactsListView_Sorting"
runat="server">
<LayoutTemplate>
<asp:Button runat="server" ID="SortButton"
CommandArgument="LastName" CommandName="Sort" Text="Sort" />
<asp:Button runat="server" ID="ClearButton"
OnClick="ClearButton_Click" Text="Clear Selection" /><br />
<table cellpadding="2" border="1" runat="server" id="tblContacts" width="640px">
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager runat="server" ID="PeopleDataPager" PageSize="20">
<Fields>
<asp:NextPreviousPagerField
ShowFirstPageButton="true" ShowLastPageButton="true"
FirstPageText="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</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") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
</td>
<td>
<asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr runat="server" style="background-color:#B0C4DE">
<td valign="top">
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
<asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
</td>
<td> </td>
</tr>
</SelectedItemTemplate>
</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="ContactsDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress]
FROM Person.Contact">
</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">
'<Snippet3>
Sub ContactsListView_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
If ContactsListView.SelectedIndex >= 0 Then
ViewState("SelectedKey") = ContactsListView.SelectedValue
Else
ViewState("SelectedKey") = Nothing
End If
End Sub
Sub ContactsListView_DataBound(ByVal sender As Object, ByVal e As EventArgs)
For i As Integer = 0 To ContactsListView.Items.Count - 1
' Ignore values that cannot be cast as integer.
Try
If Convert.ToInt32(ContactsListView.DataKeys(i).Value) = Convert.ToInt32(ViewState("SelectedKey")) Then _
ContactsListView.SelectedIndex = i
Catch
End Try
Next
End Sub
'</Snippet3>
Sub ContactsListView_PagePropertiesChanged(ByVal sender As Object, ByVal e As EventArgs)
ContactsListView.SelectedIndex = -1
End Sub
Sub ContactsListView_Sorting(ByVal sender As Object, ByVal e As ListViewSortEventArgs)
ContactsListView.SelectedIndex = -1
End Sub
Sub ClearButton_Click(ByVal sender As Object, ByVal e As EventArgs)
ViewState("SelectedKey") = Nothing
ContactsListView.SelectedIndex = -1
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView SelectedIndex Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView SelectedIndex Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
DataKeyNames="ContactID"
OnDataBound="ContactsListView_DataBound"
OnSelectedIndexChanged="ContactsListView_SelectedIndexChanged"
OnPagePropertiesChanged="ContactsListView_PagePropertiesChanged"
OnSorting="ContactsListView_Sorting"
runat="server">
<LayoutTemplate>
<asp:Button runat="server" ID="SortButton"
CommandArgument="LastName" CommandName="Sort" Text="Sort" />
<asp:Button runat="server" ID="ClearButton"
OnClick="ClearButton_Click" Text="Clear Selection" /><br />
<table cellpadding="2" border="1" runat="server" id="tblContacts" width="640px">
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager runat="server" ID="PeopleDataPager" PageSize="20">
<Fields>
<asp:NextPreviousPagerField
ShowFirstPageButton="true" ShowLastPageButton="true"
FirstPageText="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</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") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
</td>
<td>
<asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr runat="server" style="background-color:#B0C4DE">
<td valign="top">
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
<asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
</td>
<td> </td>
</tr>
</SelectedItemTemplate>
</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="ContactsDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress]
FROM Person.Contact">
</asp:SqlDataSource>
</form>
</body>
</html>
Commenti
L'evento SelectedIndexChanged viene generato quando si fa clic sul pulsante Select di un elemento, dopo che il ListView controllo gestisce l'operazione di selezione. Un pulsante Seleziona è un controllo pulsante la cui CommandName proprietà è impostata su "Seleziona". In questo modo è possibile eseguire una routine personalizzata ogni volta che si verifica questo evento, ad esempio l'aggiornamento di un'etichetta di stato con informazioni sull'elemento attualmente selezionato.
Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.
Si applica a
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