FormViewUpdatedEventArgs.AffectedRows Egenskap
Definition
Viktigt
En del information gäller för förhandsversionen av en produkt och kan komma att ändras avsevärt innan produkten blir allmänt tillgänglig. Microsoft lämnar inga garantier, uttryckliga eller underförstådda, avseende informationen som visas här.
Hämtar antalet rader som påverkas av uppdateringsåtgärden.
public:
property int AffectedRows { int get(); };public int AffectedRows { get; }member this.AffectedRows : intPublic ReadOnly Property AffectedRows As IntegerEgenskapsvärde
Antalet rader som påverkas av uppdateringsåtgärden.
Exempel
I följande exempel visas hur du använder egenskapen AffectedRows för att verifiera att en post har uppdaterats.
<%@ 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_ItemUpdated(Object sender, FormViewUpdatedEventArgs e)
{
// Use the Exception property to determine whether an exception
// occurred during the update operation.
if (e.Exception == null)
{
// Sometimes an error might occur that does not raise an
// exception, but prevents the update operation from
// completing. Use the AffectedRows property to determine
// whether the record was actually updated.
if (e.AffectedRows == 1)
{
// Use the Keys property to get the value of the key field.
String keyFieldValue = e.Keys["EmployeeID"].ToString();
// Display a confirmation message.
MessageLabel.Text = "Record " + keyFieldValue +
" updated successfully. ";
// Display the new and original values.
DisplayValues((OrderedDictionary)e.NewValues, (OrderedDictionary)e.OldValues);
}
else
{
// Display an error message.
MessageLabel.Text = "An error occurred during the update operation.";
// When an error occurs, keep the FormView
// control in edit mode.
e.KeepInEditMode = true;
}
}
else
{
// Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message;
// Use the ExceptionHandled property to indicate that the
// exception has already been handled.
e.ExceptionHandled = true;
e.KeepInEditMode = true;
}
}
void DisplayValues(OrderedDictionary newValues, OrderedDictionary oldValues)
{
MessageLabel.Text += "<br/></br>";
// Iterate through the new and old values. Display the
// values on the page.
for (int i = 0; i < oldValues.Count; i++)
{
MessageLabel.Text += "Old Value=" + oldValues[i].ToString() +
", New Value=" + newValues[i].ToString() + "<br/>";
}
MessageLabel.Text += "</br>";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdatedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdatedEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
onitemupdated="EmployeeFormView_ItemUpdated"
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>
<td>
<b>Hire Date:</b>
</td>
<td>
<%# Eval("HireDate","{0:d}") %>
</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_ItemUpdated(ByVal sender As Object, ByVal e As FormViewUpdatedEventArgs) Handles EmployeeFormView.ItemUpdated
' Use the Exception property to determine whether an exception
' occurred during the update operation.
If e.Exception Is Nothing Then
' Sometimes an error might occur that does not raise an
' exception, but prevents the update operation from
' completing. Use the AffectedRows property to determine
' whether the record was actually updated.
If e.AffectedRows = 1 Then
' Use the Keys property to get the value of the key field.
Dim keyFieldValue As String = e.Keys("EmployeeID").ToString()
' Display a confirmation message.
MessageLabel.Text = "Record " & keyFieldValue & _
" updated successfully. "
' Display the new and original values.
DisplayValues(CType(e.NewValues, OrderedDictionary), CType(e.OldValues, OrderedDictionary))
Else
' Display an error message.
MessageLabel.Text = "An error occurred during the update operation."
' When an error occurs, keep the FormView
' control in edit mode.
e.KeepInEditMode = True
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception has already been handled.
e.ExceptionHandled = True
e.KeepInEditMode = True
End If
End Sub
Sub DisplayValues(ByVal newValues As OrderedDictionary, ByVal oldValues As OrderedDictionary)
MessageLabel.Text &= "<br/></br>"
' Iterate through the new and old values. Display the
' values on the page.
Dim i As Integer
For i = 0 To oldValues.Count - 1
MessageLabel.Text &= "Old Value=" & oldValues(i).ToString() & _
", New Value=" & newValues(i).ToString() & "<br/>"
Next
MessageLabel.Text &= "</br>"
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdatedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdatedEventArgs 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>
<td>
<b>Hire Date:</b>
</td>
<td>
<%# Eval("HireDate","{0:d}") %>
</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>
Kommentarer
Använd egenskapen AffectedRows för att fastställa antalet poster som påverkas av uppdateringsåtgärden. Den här egenskapen används ofta för att kontrollera att rätt antal poster har uppdaterats i följande situationer:
Kontrollera att endast en enskild post har uppdaterats. Ibland kan en felaktigt skriven uppdateringsinstrukation uppdatera flera poster.
Kontrollera att en post uppdaterades när ett fel inträffar under uppdateringsåtgärden som inte skapar ett undantag.
Kontrollera att en post uppdaterades när en datakällakontroll som stöder konfliktidentifiering (optimistisk samtidighetskontroll), till exempel SqlDataSource kontrollerna och ObjectDataSource , har dess ConflictDetection egenskap inställd på
ConflictOptions.CompareAllValuesuppräkningsvärdet. Enligt den här inställningen kanske inte en post som har ändrats av en annan användare samtidigt uppdateras.
