DetailsViewModeEventHandler Delegato
Definizione
Importante
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Rappresenta il metodo che gestisce l'evento ModeChanging di un controllo DetailsView.
public delegate void DetailsViewModeEventHandler(System::Object ^ sender, DetailsViewModeEventArgs ^ e);public delegate void DetailsViewModeEventHandler(object sender, DetailsViewModeEventArgs e);type DetailsViewModeEventHandler = delegate of obj * DetailsViewModeEventArgs -> unitPublic Delegate Sub DetailsViewModeEventHandler(sender As Object, e As DetailsViewModeEventArgs)Parametri
- sender
- Object
Origine dell'evento.
Oggetto DetailsViewModeEventArgs che contiene i dati dell'evento.
Esempio
Nell'esempio di codice seguente viene illustrato come aggiungere a livello di codice un DetailsViewModeEventHandler delegato all'evento ModeChanging di un DetailsView 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 Page_Load(Object sender, EventArgs e)
{
// Create a new DetailsView object.
DetailsView customerDetailsView = new DetailsView();
// Set the DetailsView object's properties.
customerDetailsView.ID = "CustomerDetailsView";
customerDetailsView.DataSourceID = "DetailsViewSource";
customerDetailsView.AutoGenerateRows = true;
customerDetailsView.AutoGenerateEditButton = true;
customerDetailsView.AllowPaging = true;
customerDetailsView.DataKeyNames = new String[1] { "CustomerID" };
// Programmatically register the event-handling method
// for the ItemInserted event of a DetailsView control.
customerDetailsView.ModeChanging += new DetailsViewModeEventHandler(this.CustomerDetailsView_ModeChanging);
// Add the DetailsView object to the Controls collection
// of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(customerDetailsView);
}
void CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
{
// Use the sender parameter to access the DetailsView
// control that raised the event.
DetailsView customerDetailsView = (DetailsView)sender;
// Use the NewMode property to determine the mode to which the
// DetailsView control is transitioning.
switch (e.NewMode)
{
case DetailsViewMode.Edit:
// Hide the pager row and clear the Label control
// when transitioning to edit mode.
customerDetailsView.AllowPaging = false;
MessageLabel.Text = "";
break;
case DetailsViewMode.ReadOnly:
// Display the pager row and confirmation message
// when transitioning to edit mode.
customerDetailsView.AllowPaging = true;
if (e.CancelingEdit)
{
MessageLabel.Text = "Update canceled.";
}
else
{
MessageLabel.Text = "Update completed.";
}
break;
case DetailsViewMode.Insert:
// Cancel the mode change if the DetailsView
// control attempts to transition to insert
// mode.
e.Cancel = true;
break;
default:
MessageLabel.Text = "Unsupported mode.";
break;
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewModeEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewModeEventHandler Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated DetailsView control. -->
<asp:PlaceHolder id="DetailsViewPlaceHolder"
runat="server"/>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)
' Create a new DetailsView object.
Dim customerDetailsView As New DetailsView()
' Set the DetailsView object's properties.
customerDetailsView.ID = "CustomerDetailsView"
customerDetailsView.DataSourceID = "DetailsViewSource"
customerDetailsView.AutoGenerateRows = True
customerDetailsView.AutoGenerateEditButton = True
customerDetailsView.AllowPaging = True
Dim keyArray() As String = {"CustomerID"}
customerDetailsView.DataKeyNames = keyArray
' Programmatically register the event-handling method
' for the ItemInserted event of a DetailsView control.
AddHandler customerDetailsView.ModeChanging, AddressOf CustomerDetailsView_ModeChanging
' Add the DetailsView object to the Controls collection
' of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(customerDetailsView)
End Sub
Sub CustomerDetailsView_ModeChanging(ByVal sender As Object, ByVal e As DetailsViewModeEventArgs)
' Use the sender parameter to access the DetailsView
' control that raised the event.
Dim customerDetailsView As DetailsView = CType(sender, DetailsView)
' Use the NewMode property to determine the mode to which the
' DetailsView control is transitioning.
Select Case e.NewMode
Case DetailsViewMode.Edit
' Hide the pager row and clear the Label control
' when transitioning to edit mode.
customerDetailsView.AllowPaging = False
MessageLabel.Text = ""
Case DetailsViewMode.ReadOnly
' Display the pager row and confirmation message
' when transitioning to edit mode.
customerDetailsView.AllowPaging = True
If e.CancelingEdit Then
MessageLabel.Text = "Update canceled."
Else
MessageLabel.Text = "Update completed."
End If
Case DetailsViewMode.Insert
' Cancel the mode change if the DetailsView
' control attempts to transition to insert
' mode.
e.Cancel = True
Case Else
MessageLabel.Text = "Unsupported mode."
End Select
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewModeEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewModeEventHandler Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated DetailsView control. -->
<asp:PlaceHolder id="DetailsViewPlaceHolder"
runat="server"/>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Nell'esempio di codice seguente viene illustrato come aggiungere in modo dichiarativo un DetailsViewModeEventHandler delegato all'evento ModeChanging di un DetailsView 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 CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
{
// Use the NewMode property to determine the mode to which the
// DetailsView control is transitioning.
switch (e.NewMode)
{
case DetailsViewMode.Edit:
// Hide the pager row and clear the Label control
// when transitioning to edit mode.
CustomerDetailsView.AllowPaging = false;
MessageLabel.Text = "";
break;
case DetailsViewMode.ReadOnly:
// Display the pager row and confirmation message
// when transitioning to edit mode.
CustomerDetailsView.AllowPaging = true;
if (e.CancelingEdit)
{
MessageLabel.Text = "Update canceled.";
}
else
{
MessageLabel.Text = "Update completed.";
}
break;
case DetailsViewMode.Insert:
// Cancel the mode change if the DetailsView
// control attempts to transition to insert
// mode.
e.Cancel = true;
break;
default:
MessageLabel.Text = "Unsupported mode.";
break;
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewModeEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewModeEventHandler Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
datakeynames="CustomerID"
autogeneraterows="true"
autogenerateeditbutton="true"
allowpaging="true"
onmodechanging="CustomerDetailsView_ModeChanging"
runat="server">
</asp:detailsview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" autoeventwireup="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub CustomerDetailsView_ModeChanging(ByVal sender As Object, ByVal e As DetailsViewModeEventArgs) Handles CustomerDetailsView.ModeChanging
' Use the NewMode property to determine the mode to which the
' DetailsView control is transitioning.
Select Case e.NewMode
Case DetailsViewMode.Edit
' Hide the pager row and clear the Label control
' when transitioning to edit mode.
CustomerDetailsView.AllowPaging = False
MessageLabel.Text = ""
Case DetailsViewMode.ReadOnly
' Display the pager row and confirmation message
' when transitioning to edit mode.
CustomerDetailsView.AllowPaging = True
If e.CancelingEdit Then
MessageLabel.Text = "Update canceled."
Else
MessageLabel.Text = "Update completed."
End If
Case DetailsViewMode.Insert
' Cancel the mode change if the DetailsView
' control attempts to transition to insert
' mode.
e.Cancel = True
Case Else
MessageLabel.Text = "Unsupported mode."
End Select
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewModeEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewModeEventHandler Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
datakeynames="CustomerID"
autogeneraterows="true"
autogenerateeditbutton="true"
allowpaging="true"
runat="server">
</asp:detailsview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Commenti
L'evento ModeChanging viene generato quando un DetailsView controllo tenta di modificare tra modifica, inserimento e modalità di sola lettura, ma prima che la modalità cambi effettivamente. In questo modo è possibile fornire un gestore eventi che esegue una routine personalizzata, ad esempio la configurazione del controllo per una modalità specifica o l'annullamento DetailsView della modifica della modalità, ogni volta che si verifica questo evento.
Quando si crea un delegato DetailsViewModeEventHandler, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato. Per altre informazioni sui delegati del gestore eventi, vedere Gestione e generazione di eventi.
Metodi di estensione
| GetMethodInfo(Delegate) |
Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato. |
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