ListView.SelectedIndexChanged Evento
Definição
Importante
Algumas informações dizem respeito a um produto pré-lançado que pode ser substancialmente modificado antes de ser lançado. A Microsoft não faz garantias, de forma expressa ou implícita, em relação à informação aqui apresentada.
Ocorre quando o botão Select de um item é clicado, depois de o ListView controlo tratar da operação de seleção.
public:
event EventHandler ^ SelectedIndexChanged;public event EventHandler SelectedIndexChanged;member this.SelectedIndexChanged : EventHandler Public Custom Event SelectedIndexChanged As EventHandler Tipo de Evento
Exemplos
O exemplo seguinte mostra como criar um gestor de eventos para o SelectedIndexChanged evento.
<%@ 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>
Observações
O SelectedIndexChanged evento é ativado quando o botão Select de um item é carregado, depois de o controlo ListView tratar da operação de seleção. (Um botão Select é um controlo de botão cuja CommandName propriedade está definida como "Select".) Isto permite-lhe executar uma rotina personalizada sempre que este evento ocorre, como atualizar uma etiqueta de estado com informações sobre o item atualmente selecionado.
Para mais informações sobre como gerir eventos, consulte Gestão e Levantamento de Eventos.