GridView.OnRowCommand(GridViewCommandEventArgs) Metodo
Definizione
Importante
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Genera l'evento RowCommand.
protected:
virtual void OnRowCommand(System::Web::UI::WebControls::GridViewCommandEventArgs ^ e);protected virtual void OnRowCommand (System.Web.UI.WebControls.GridViewCommandEventArgs e);abstract member OnRowCommand : System.Web.UI.WebControls.GridViewCommandEventArgs -> unit
override this.OnRowCommand : System.Web.UI.WebControls.GridViewCommandEventArgs -> unitProtected Overridable Sub OnRowCommand (e As GridViewCommandEventArgs)Parametri
GridViewCommandEventArgs in cui sono contenuti i dati dell'evento.
Esempio
Per accompagnare questo argomento, è disponibile un progetto di sito Web di Visual Studio con codice sorgente.
Nell'esempio seguente viene illustrato come fornire un metodo di gestione eventi per l'evento RowCommand . Quando si fa clic sul pulsante Aggiungi per una determinata riga del GridView controllo, il nome del cliente selezionato viene aggiunto a un ListBox controllo.
<%@ 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 ContactsGridView_RowCommand(Object sender, GridViewCommandEventArgs e)
{
// If multiple buttons are used in a GridView control, use the
// CommandName property to determine which button was clicked.
if(e.CommandName=="Add")
{
// Convert the row index stored in the CommandArgument
// property to an Integer.
int index = Convert.ToInt32(e.CommandArgument);
// Retrieve the row that contains the button clicked
// by the user from the Rows collection.
GridViewRow row = ContactsGridView.Rows[index];
// Create a new ListItem object for the contact in the row.
ListItem item = new ListItem();
item.Text = Server.HtmlDecode(row.Cells[2].Text) + " " +
Server.HtmlDecode(row.Cells[3].Text);
// If the contact is not already in the ListBox, add the ListItem
// object to the Items collection of the ListBox control.
if (!ContactsListBox.Items.Contains(item))
{
ContactsListBox.Items.Add(item);
}
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView RowCommand Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView RowCommand Example</h3>
<table width="100%">
<tr>
<td style="width:50%">
<asp:gridview id="ContactsGridView"
datasourceid="ContactsSource"
allowpaging="true"
autogeneratecolumns="false"
onrowcommand="ContactsGridView_RowCommand"
runat="server">
<columns>
<asp:buttonfield buttontype="Link"
commandname="Add"
text="Add"/>
<asp:boundfield datafield="ContactID"
headertext="Contact ID"/>
<asp:boundfield datafield="FirstName"
headertext="First Name"/>
<asp:boundfield datafield="LastName"
headertext="Last Name"/>
</columns>
</asp:gridview>
</td>
<td style="vertical-align:top; width:50%">
Contacts: <br/>
<asp:listbox id="ContactsListBox"
runat="server" Height="200px" Width="200px"/>
</td>
</tr>
</table>
<!-- 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="ContactsSource"
selectcommand="Select [ContactID], [FirstName], [LastName] From Person.Contact"
connectionstring="<%$ ConnectionStrings:AdventureWorks_DataConnectionString%>"
runat="server"/>
</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 ContactsGridView_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)
' If multiple buttons are used in a GridView control, use the
' CommandName property to determine which button was clicked.
If e.CommandName = "Add" Then
' Convert the row index stored in the CommandArgument
' property to an Integer.
Dim index As Integer = Convert.ToInt32(e.CommandArgument)
' Retrieve the row that contains the button clicked
' by the user from the Rows collection.
Dim row As GridViewRow = ContactsGridView.Rows(index)
' Create a new ListItem object for the contact in the row.
Dim item As New ListItem()
item.Text = Server.HtmlDecode(row.Cells(2).Text) & " " & _
Server.HtmlDecode(row.Cells(3).Text)
' If the contact is not already in the ListBox, add the ListItem
' object to the Items collection of the ListBox control.
If Not ContactsListBox.Items.Contains(item) Then
ContactsListBox.Items.Add(item)
End If
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>GridView RowCommand Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView RowCommand Example</h3>
<table width="100%">
<tr>
<td style="width:50%">
<asp:gridview id="ContactsGridView"
datasourceid="ContactsSource"
allowpaging="true"
autogeneratecolumns="false"
onrowcommand="ContactsGridView_RowCommand"
runat="server">
<columns>
<asp:buttonfield buttontype="Link"
commandname="Add"
text="Add"/>
<asp:boundfield datafield="ContactID"
headertext="Contact ID"/>
<asp:boundfield datafield="FirstName"
headertext="First Name"/>
<asp:boundfield datafield="LastName"
headertext="Last Name"/>
</columns>
</asp:gridview>
</td>
<td style="vertical-align:top; width:50%">
Contacts: <br/>
<asp:listbox id="ContactsListBox"
runat="server" Height="200px" Width="200px"/>
</td>
</tr>
</table>
<!-- 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="ContactsSource"
selectcommand="Select [ContactID], [FirstName], [LastName] From Person.Contact"
connectionstring="<%$ ConnectionStrings:AdventureWorks_DataConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Commenti
L'evento RowCommand viene generato quando viene fatto clic su un pulsante nel GridView controllo. Ciò consente di fornire un metodo di gestione eventi che esegue una routine personalizzata ogni volta che si verifica questo evento.
Quando viene generato un evento, il gestore dell'evento viene richiamato tramite un delegato. Per altre informazioni, vedere la gestione e generazione di eventi.
Il metodo OnRowCommand consente inoltre alle classi derivate di gestire l'evento senza associare un delegato. È la tecnica consigliata per la gestione dell'evento in una classe derivata.
Note per gli eredi
Quando si esegue l'override di OnRowCommand(GridViewCommandEventArgs) in una classe derivata, verificare di chiamare il metodo OnRowCommand(GridViewCommandEventArgs) della classe di base in modo che i delegati registrati ricevano l'evento.
