GridView.RowCancelingEdit 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 fatto clic sul pulsante Annulla di una riga in modalità di modifica, ma prima che la riga esca da tale modalità.
public:
event System::Web::UI::WebControls::GridViewCancelEditEventHandler ^ RowCancelingEdit;public event System.Web.UI.WebControls.GridViewCancelEditEventHandler RowCancelingEdit;member this.RowCancelingEdit : System.Web.UI.WebControls.GridViewCancelEditEventHandler Public Custom Event RowCancelingEdit As GridViewCancelEditEventHandler Tipo evento
Esempio
Nell'esempio seguente viene illustrato come utilizzare l'evento RowCancelingEdit per visualizzare un messaggio di annullamento quando l'utente annulla l'operazione di aggiornamento di un GridView 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 CustomersGridView_RowCancelingEdit(Object sender, GridViewCancelEditEventArgs e)
{
// Retrieve the row that raised the event from the Rows
// collection of the GridView control.
GridViewRow row = CustomersGridView.Rows[e.RowIndex];
// The update operation was canceled. Display the
// primary key of the row. In this example, the primary
// key is displayed in the second column of the GridView
// control. To access the text of the column, use the Cells
// collection of the row.
Message.Text = "Update for item " + row.Cells[1].Text + " Canceled.";
}
void CustomersGridView_RowEditing(Object sender, GridViewEditEventArgs e)
{
// The GridView control is entering edit mode. Clear the message label.
Message.Text = "";
}
void CustomersGridView_RowUpdated(Object sender, GridViewUpdatedEventArgs e)
{
// The update operation was successful. Clear the message label.
Message.Text = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView RowCancelingEdit Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView RowCancelingEdit Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames attribute as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogenerateeditbutton="true"
allowpaging="true"
datakeynames="CustomerID"
onrowcancelingedit="CustomersGridView_RowCancelingEdit"
onrowediting="CustomersGridView_RowEditing"
onrowupdated="CustomersGridView_RowUpdated"
runat="server">
</asp:gridview>
<!-- 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="CustomersSqlDataSource"
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">
</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 CustomersGridView_RowCancelingEdit(ByVal sender As Object, ByVal e As GridViewCancelEditEventArgs)
' Retrieve the row that raised the event from the Rows
' collection of the GridView control.
Dim row As GridViewRow = CustomersGridView.Rows(e.RowIndex)
' The update operation was canceled. Display the
' primary key of the row. In this example, the primary
' key is displayed in the second column of the GridView
' control. To access the text of the column, use the Cells
' collection of the row.
Message.Text = "Update for item " & row.Cells(1).Text & " Canceled."
End Sub
Sub CustomersGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
' The GridView control is entering edit mode. Clear the message label.
Message.Text = ""
End Sub
Sub CustomersGridView_RowUpdated(ByVal sender As Object, ByVal e As GridViewUpdatedEventArgs)
' The update operation was successful. Clear the message label.
Message.Text = ""
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView RowCancelingEdit Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView RowCancelingEdit Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames attribute as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogenerateeditbutton="true"
allowpaging="true"
datakeynames="CustomerID"
onrowcancelingedit="CustomersGridView_RowCancelingEdit"
onrowediting="CustomersGridView_RowEditing"
onrowupdated="CustomersGridView_RowUpdated"
runat="server">
</asp:gridview>
<!-- 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="CustomersSqlDataSource"
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">
</asp:sqldatasource>
</form>
</body>
</html>
Nell'esempio seguente viene illustrato come utilizzare l'evento RowCancelingEdit per annullare l'operazione di aggiornamento quando l'origine dati viene impostata a livello di codice.
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
// Create a new table.
DataTable taskTable = new DataTable("TaskList");
// Create the columns.
taskTable.Columns.Add("Id", typeof(int));
taskTable.Columns.Add("Description", typeof(string));
taskTable.Columns.Add("IsComplete", typeof(bool) );
//Add data to the new table.
for (int i = 0; i < 20; i++)
{
DataRow tableRow = taskTable.NewRow();
tableRow["Id"] = i;
tableRow["Description"] = "Task " + i.ToString();
tableRow["IsComplete"] = false;
taskTable.Rows.Add(tableRow);
}
//Persist the table in the Session object.
Session["TaskTable"] = taskTable;
//Bind data to the GridView control.
BindData();
}
}
protected void TaskGridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
TaskGridView.PageIndex = e.NewPageIndex;
//Bind data to the GridView control.
BindData();
}
protected void TaskGridView_RowEditing(object sender, GridViewEditEventArgs e)
{
//Set the edit index.
TaskGridView.EditIndex = e.NewEditIndex;
//Bind data to the GridView control.
BindData();
}
protected void TaskGridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
//Reset the edit index.
TaskGridView.EditIndex = -1;
//Bind data to the GridView control.
BindData();
}
protected void TaskGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
//Retrieve the table from the session object.
DataTable dt = (DataTable)Session["TaskTable"];
//Update the values.
GridViewRow row = TaskGridView.Rows[e.RowIndex];
dt.Rows[row.DataItemIndex]["Id"] = ((TextBox)(row.Cells[1].Controls[0])).Text;
dt.Rows[row.DataItemIndex]["Description"] = ((TextBox)(row.Cells[2].Controls[0])).Text;
dt.Rows[row.DataItemIndex]["IsComplete"] = ((CheckBox)(row.Cells[3].Controls[0])).Checked;
//Reset the edit index.
TaskGridView.EditIndex = -1;
//Bind data to the GridView control.
BindData();
}
private void BindData()
{
TaskGridView.DataSource = Session["TaskTable"];
TaskGridView.DataBind();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>GridView example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="TaskGridView" runat="server"
AutoGenerateEditButton="True"
AllowPaging="true"
OnRowEditing="TaskGridView_RowEditing"
OnRowCancelingEdit="TaskGridView_RowCancelingEdit"
OnRowUpdating="TaskGridView_RowUpdating"
OnPageIndexChanging="TaskGridView_PageIndexChanging">
</asp:GridView>
</div>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Page_Load()
If Not Page.IsPostBack Then
' Create a new table.
Dim taskTable As New DataTable("TaskList")
' Create the columns.
taskTable.Columns.Add("Id", GetType(Integer))
taskTable.Columns.Add("Description", GetType(String))
taskTable.Columns.Add("IsComplete", GetType(Boolean))
'Add data to the new table.
For i = 0 To 19
Dim tableRow = taskTable.NewRow()
tableRow("Id") = i
tableRow("Description") = "Task " + i.ToString()
tableRow("IsComplete") = False
taskTable.Rows.Add(tableRow)
Next
'Persist the table in the Session object.
Session("TaskTable") = taskTable
'Bind data to the GridView control.
BindData()
End If
End Sub
Protected Sub TaskGridView_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)
TaskGridView.PageIndex = e.NewPageIndex
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
'Set the edit index.
TaskGridView.EditIndex = e.NewEditIndex
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowCancelingEdit()
'Reset the edit index.
TaskGridView.EditIndex = -1
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
'Retrieve the table from the session object.
Dim dt = CType(Session("TaskTable"), DataTable)
'Update the values.
Dim row = TaskGridView.Rows(e.RowIndex)
dt.Rows(row.DataItemIndex)("Id") = (CType((row.Cells(1).Controls(0)), TextBox)).Text
dt.Rows(row.DataItemIndex)("Description") = (CType((row.Cells(2).Controls(0)), TextBox)).Text
dt.Rows(row.DataItemIndex)("IsComplete") = (CType((row.Cells(3).Controls(0)), CheckBox)).Checked
'Reset the edit index.
TaskGridView.EditIndex = -1
'Bind data to the GridView control.
BindData()
End Sub
Private Sub BindData()
TaskGridView.DataSource = Session("TaskTable")
TaskGridView.DataBind()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>GridView example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="TaskGridView" runat="server"
AutoGenerateEditButton="True"
AllowPaging="true"
OnRowEditing="TaskGridView_RowEditing"
OnRowCancelingEdit="TaskGridView_RowCancelingEdit"
OnRowUpdating="TaskGridView_RowUpdating"
OnPageIndexChanging="TaskGridView_PageIndexChanging">
</asp:GridView>
</div>
</form>
</body>
</html>
Commenti
L'evento RowCancelingEdit viene generato quando si fa clic sul pulsante Annulla di una riga in modalità di modifica, ma prima che la riga esce dalla modalità di modifica. In questo modo è possibile fornire un metodo di gestione degli eventi che esegue una routine personalizzata, ad esempio l'arresto dell'operazione di annullamento se la riga viene inserita in uno stato indesiderato, ogni volta che si verifica questo evento.
Un GridViewCancelEditEventArgs oggetto viene passato al metodo di gestione degli eventi, che consente di determinare l'indice della riga corrente e di indicare che l'operazione di annullamento deve essere arrestata. Per arrestare l'operazione di annullamento, impostare la Cancel proprietà dell'oggetto GridViewCancelEditEventArgs su true.
Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.
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