ListView.PagePropertiesChanging Event
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Occurs when the page properties change, but before the ListView control sets the new values.
public:
event EventHandler<System::Web::UI::WebControls::PagePropertiesChangingEventArgs ^> ^ PagePropertiesChanging;public event EventHandler<System.Web.UI.WebControls.PagePropertiesChangingEventArgs> PagePropertiesChanging;member this.PagePropertiesChanging : EventHandler<System.Web.UI.WebControls.PagePropertiesChangingEventArgs> Public Custom Event PagePropertiesChanging As EventHandler(Of PagePropertiesChangingEventArgs) Event Type
Examples
The following example shows how create an event handler for the PagePropertiesChanging event.
<%@ 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">
// <Snippet2>
protected void DeleteButton_Click(object sender, EventArgs e)
{
//Check if an item is selected to delete it.
if (ContactsListView.SelectedIndex >= 0)
ContactsListView.DeleteItem(ContactsListView.SelectedIndex);
else
Message.Text = "No contact was selected.";
}
// </Snippet2>
protected void ContactsListView_ItemDeleted(object sender, ListViewDeletedEventArgs e)
{
//Check if an exception occurred to display an error message.
if (e.Exception != null)
{
Message.Text = "An exception occurred deleting the contact.";
e.ExceptionHandled = true;
}
else
{
// Clear the selected index.
ContactsListView.SelectedIndex = -1;
}
}
protected void ContactsListView_PagePropertiesChanging(object sender,
PagePropertiesChangingEventArgs e)
{
//Clear the selected index.
ContactsListView.SelectedIndex = -1;
}
protected void Page_Load(object sender, EventArgs e)
{
//Clear the message label.
Message.Text = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView DeleteItem Example</title>
<style type="text/css">
body
{
font-size: 10pt;
font-family: Trebuchet MS, Arial, Tahoma;
text-align:center;
}
.item { background-color: #E0FFFF }
.selectedItem { background-color: #B0E0E6 }
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView DeleteItem Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
DataKeyNames="ContactID"
OnItemDeleted="ContactsListView_ItemDeleted"
OnPagePropertiesChanging="ContactsListView_PagePropertiesChanging"
runat="server" >
<LayoutTemplate>
<table cellpadding="2" width="640px" id="tblProducts" runat="server">
<tr runat="server">
<th runat="server"> </th>
<th runat="server">ID</th>
<th runat="server">Account Number</th>
<th runat="server">LastName</th>
<th runat="server">Preferred Vendor</th>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager ID="ContactsDataPager" runat="server" PageSize="15">
<Fields>
<asp:NextPreviousPagerField ButtonType="Button"
ShowFirstPageButton="true"
ShowNextPageButton="false"
ShowPreviousPageButton="false" />
<asp:NumericPagerField ButtonCount="10" />
<asp:NextPreviousPagerField ButtonType="Button"
ShowLastPageButton="true"
ShowNextPageButton="false"
ShowPreviousPageButton="false" />
</Fields>
</asp:DataPager>
</LayoutTemplate>
<ItemTemplate>
<tr class="item" runat="server">
<td>
<asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
</td>
<td>
<asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
</td>
<td>
<asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr class="selectedItem" runat="server">
<td> </td>
<td>
<asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
</td>
<td>
<asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br />
<br />
<asp:Button ID="DeleteButton"
Text="Delete Selected Contact"
OnClick="DeleteButton_Click"
runat="server" />
<br />
<asp:Label ID="Message"
ForeColor="Red"
runat="server"/>
<br/>
<!-- 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="ContactsDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT ContactID, FirstName, LastName, EmailAddress
FROM Person.Contact"
DeleteCommand="DELETE FROM Person.Contact WHERE (ContactID = @ContactID)" >
</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">
' <Snippet2>
Protected Sub DeleteButton_Click(ByVal sender As Object, ByVal e As EventArgs)
' Check if an item is selected to delete it.
If ContactsListView.SelectedIndex >= 0 Then
ContactsListView.DeleteItem(ContactsListView.SelectedIndex)
Else
Message.Text = "No contact was selected."
End If
End Sub
' </Snippet2>
Protected Sub ContactsListView_ItemDeleted(ByVal sender As Object, _
ByVal e As ListViewDeletedEventArgs)
' Check if an exception occurred to display an error message.
If Not (e.Exception Is Nothing) Then
Message.Text = "An exception occurred deleting the contact."
e.ExceptionHandled = True
Else
' Clear the selected index.
ContactsListView.SelectedIndex = -1
End If
End Sub
Protected Sub ContactsListView_PagePropertiesChanging(ByVal sender As Object, _
ByVal e As PagePropertiesChangingEventArgs)
' Clear the selected index.
ContactsListView.SelectedIndex = -1
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
' Clear the message label.
Message.Text = ""
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView DeleteItem Example</title>
<style type="text/css">
body
{
font-size: 10pt;
font-family: Trebuchet MS, Arial, Tahoma;
text-align:center;
}
.item { background-color: #E0FFFF }
.selectedItem { background-color: #B0E0E6 }
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView DeleteItem Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
DataKeyNames="ContactID"
OnItemDeleted="ContactsListView_ItemDeleted"
OnPagePropertiesChanging="ContactsListView_PagePropertiesChanging"
runat="server" >
<LayoutTemplate>
<table cellpadding="2" width="640px" id="tblProducts" runat="server">
<tr runat="server">
<th runat="server"> </th>
<th runat="server">ID</th>
<th runat="server">Account Number</th>
<th runat="server">LastName</th>
<th runat="server">Preferred Vendor</th>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager ID="ContactsDataPager" runat="server" PageSize="15">
<Fields>
<asp:NextPreviousPagerField ButtonType="Button"
ShowFirstPageButton="true"
ShowNextPageButton="false"
ShowPreviousPageButton="false" />
<asp:NumericPagerField ButtonCount="10" />
<asp:NextPreviousPagerField ButtonType="Button"
ShowLastPageButton="true"
ShowNextPageButton="false"
ShowPreviousPageButton="false" />
</Fields>
</asp:DataPager>
</LayoutTemplate>
<ItemTemplate>
<tr class="item" runat="server">
<td>
<asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
</td>
<td>
<asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
</td>
<td>
<asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr class="selectedItem" runat="server">
<td> </td>
<td>
<asp:Label ID="ContactIDLabel" runat="server" Text='<%# Eval("ContactID") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
</td>
<td>
<asp:Label ID="LastNameLabel" runat="server" Text='<%# Eval("LastName") %>' />
</td>
<td>
<asp:Label ID="EmailLabel" runat="server" Text='<%# Eval("EmailAddress") %>' />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br />
<br />
<asp:Button ID="DeleteButton"
Text="Delete Selected Contact"
OnClick="DeleteButton_Click"
runat="server" />
<br />
<asp:Label ID="Message"
ForeColor="Red"
runat="server"/>
<br/>
<!-- 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="ContactsDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT ContactID, FirstName, LastName, EmailAddress
FROM Person.Contact"
DeleteCommand="DELETE FROM Person.Contact WHERE (ContactID = @ContactID)" >
</asp:SqlDataSource>
</form>
</body>
</html>
Remarks
The PagePropertiesChanging event is raised when the page properties change, but before the ListView control sets the new values by using the SetPageProperties method. This enables you to perform a custom routine whenever this event occurs, such as clearing the SelectedIndex or EditIndex properties.
A PagePropertiesChangingEventArgs object is passed to the event handler, which enables you to determine the index of the first record displayed on the page. It also lets you determine the maximum number of items to display on a single page.
For more information about how to handle events, see Handling and Raising Events.
Applies to
See also
Tee yhteistyötä kanssamme GitHubissa
Tämän sisällön lähde on GitHubissa, jossa voit myös luoda ja tarkastella ongelmia ja pull-pyyntöjä. Katso lisätietoja osallistujan oppaasta.
