FormView.ItemUpdating Kejadian
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Terjadi ketika tombol Perbarui dalam FormView kontrol diklik, tetapi sebelum operasi pembaruan.
public:
event System::Web::UI::WebControls::FormViewUpdateEventHandler ^ ItemUpdating;public event System.Web.UI.WebControls.FormViewUpdateEventHandler ItemUpdating;member this.ItemUpdating : System.Web.UI.WebControls.FormViewUpdateEventHandler Public Custom Event ItemUpdating As FormViewUpdateEventHandler Jenis Acara
Contoh
Contoh berikut menunjukkan cara menggunakan ItemUpdating peristiwa untuk membatalkan operasi pembaruan.
<%@ 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 EmployeeFormView_ItemUpdating(Object sender, FormViewUpdateEventArgs e)
{
// Validate the field values entered by the user. This
// example determines whether the user left any fields
// empty. The names of the empty fields are added to
// an ArrayList object.
// Use the NewValues property to access the new
// values entered by the user.
ArrayList emptyFieldList = ValidateFields((OrderedDictionary)e.NewValues);
if (emptyFieldList.Count > 0)
{
// The user left some fields empty. Display an error message.
// Use the Keys property to retrieve the key field value.
String keyValue = e.Keys["EmployeeID"].ToString();
MessageLabel.Text = "You must enter a value for each field of record " +
keyValue + ".<br/>The following fields are missing:<br/><br/>";
// Display the missing fields.
foreach (String value in emptyFieldList)
{
// Use the OldValues property to access the original value
// of a field.
MessageLabel.Text += value + " - Original Value = " +
e.OldValues[value].ToString() + "<br />";
}
// Cancel the update operation.
e.Cancel = true;
}
else
{
// The field values passed validation. Clear the
// error message label.
MessageLabel.Text = "";
}
}
ArrayList ValidateFields(OrderedDictionary list)
{
// Create an ArrayList object to store the
// names of any empty fields.
ArrayList emptyFieldList = new ArrayList();
// Iterate though the field values entered by
// the user and check for an empty field.
foreach (DictionaryEntry entry in list)
{
if (entry.Value.Equals(""))
{
// Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString());
}
}
return emptyFieldList;
}
void EmployeeFormView_ModeChanged(Object sender, EventArgs e)
{
// Clear the error message label.
MessageLabel.Text = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
onitemupdating="EmployeeFormView_ItemUpdating"
onmodechanged="EmployeeFormView_ModeChanged"
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<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="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
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 EmployeeFormView_ItemUpdating(ByVal sender As Object, ByVal e As FormViewUpdateEventArgs) Handles EmployeeFormView.ItemUpdating
' Validate the field values entered by the user. This
' example determines whether the user left any fields
' empty. The names of the empty fields are added to
' an ArrayList object.
' Use the NewValues property to access the new
' values entered by the user.
Dim emptyFieldList As ArrayList = ValidateFields(CType(e.NewValues, OrderedDictionary))
If emptyFieldList.Count > 0 Then
' The user left some fields empty. Display an error message.
' Use the Keys property to retrieve the key field value.
Dim keyValue As String = e.Keys("EmployeeID").ToString()
MessageLabel.Text = "You must enter a value for each field of record " & _
keyValue & ".<br/>The following fields are missing:<br/><br/>"
' Display the missing fields.
Dim value As String
For Each value In emptyFieldList
' Use the OldValues property access the original value
' of a field.
MessageLabel.Text &= value & " - Original Value = " & _
e.OldValues(value).ToString() & "<br />"
Next
' Cancel the update operation.
e.Cancel = True
Else
' The field values passed validation. Clear the
' error message label.
MessageLabel.Text = ""
End If
End Sub
Function ValidateFields(ByVal list As OrderedDictionary) As ArrayList
' Create an ArrayList object to store the
' names of any empty fields.
Dim emptyFieldList As New ArrayList()
' Iterate though the field values entered by
' the user and check for an empty field.
Dim entry As DictionaryEntry
For Each entry In list
If entry.Value.Equals("") Then
' Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString())
End If
Next
Return emptyFieldList
End Function
Sub EmployeeFormView_ModeChanged(ByVal sender As Object, ByVal e As EventArgs) Handles EmployeeFormView.ModeChanged
' Clear the error message label.
MessageLabel.Text = ""
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<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="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Keterangan
FormView Kontrol menaikkan ItemUpdating peristiwa saat tombol Perbarui (tombol dengan propertinya CommandName diatur ke "Perbarui") dalam kontrol diklik, tetapi sebelum FormView kontrol memperbarui rekaman. Ini memungkinkan Anda untuk menyediakan metode penanganan peristiwa yang melakukan rutinitas kustom, seperti HTML yang mengodekan nilai rekaman sebelum memperbaruinya di sumber data, setiap kali peristiwa ini terjadi.
Objek FormViewUpdateEventArgs diteruskan ke metode penanganan peristiwa, yang memungkinkan Anda menentukan nilai argumen perintah opsional yang dikirim ke FormView kontrol dan untuk menunjukkan bahwa operasi pembaruan harus dibatalkan. Nilai argumen perintah sesuai dengan CommandArgument properti tombol Perbarui. CommandArgument Saat properti tombol Perbarui diatur, gunakan CommandArgument properti untuk menentukan nilai argumen perintah. Untuk membatalkan operasi pembaruan, atur properti ke Canceltrue. Anda juga dapat membaca atau mengubah nilai baru yang dimasukkan oleh pengguna dengan menggunakan Keys properti dan NewValues . Properti Keys berisi bidang kunci, sementara NewValues properti berisi bidang non-kunci. Jika Anda perlu mengakses nilai bidang non-kunci asli, gunakan OldValues properti .
Untuk informasi selengkapnya tentang cara menangani peristiwa, lihat Menangani dan Menaikkan Peristiwa.
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