ListView.Sorting 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 a sort operation is requested, but before the ListView control handles the sort operation.
public:
event EventHandler<System::Web::UI::WebControls::ListViewSortEventArgs ^> ^ Sorting;public event EventHandler<System.Web.UI.WebControls.ListViewSortEventArgs> Sorting;member this.Sorting : EventHandler<System.Web.UI.WebControls.ListViewSortEventArgs> Public Custom Event Sorting As EventHandler(Of ListViewSortEventArgs) Event Type
Examples
The following example shows how create an event handler for the Sorting 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>
void ContactsListView_Sorting(Object sender, ListViewSortEventArgs e)
{
// Check the sort direction to set the image URL accordingly.
string imgUrl;
if (e.SortDirection == SortDirection.Ascending)
imgUrl = "~/images/ascending.gif";
else
imgUrl = "~/images/descending.gif";
// Check which field is being sorted
// to set the visibility of the image controls.
Image sortImage1 = (Image) ContactsListView.FindControl("SortImage1");
Image sortImage2 = (Image)ContactsListView.FindControl("SortImage2");
Image sortImage3 = (Image)ContactsListView.FindControl("SortImage3");
switch (e.SortExpression)
{
case "FirstName":
sortImage1.Visible = true;
sortImage1.ImageUrl = imgUrl;
sortImage2.Visible = false;
sortImage3.Visible = false;
break;
case "LastName":
sortImage1.Visible = false;
sortImage2.Visible = true;
sortImage2.ImageUrl = imgUrl;
sortImage3.Visible = false;
break;
case "EmailAddress":
sortImage1.Visible = false;
sortImage2.Visible = false;
sortImage3.Visible = true;
sortImage3.ImageUrl = imgUrl;
break;
}
}
//</Snippet2>
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView Sorting Example</title>
<style type="text/css">
body { font: 10pt Trebuchet MS, Arial, Tahoma; }
td { border: 1px solid #E6E6FA; }
.header { background: #B0C4DE; }
.alternatingItem { background: #edf5fd; }
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView Sorting Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
OnSorting="ContactsListView_Sorting"
runat="server">
<LayoutTemplate>
<table width="640px" runat="server" id="tblContacts">
<tr class="header" align="center" runat="server">
<td>
<asp:LinkButton runat="server" ID="SortByFirstNameButton"
CommandName="Sort" Text="First Name"
CommandArgument="FirstName"/>
<asp:Image runat="server" ID="SortImage1"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
<td>
<asp:LinkButton runat="server" ID="SortByLastNameButton"
CommandName="Sort" Text="Last Name"
CommandArgument="LastName" />
<asp:Image runat="server" ID="SortImage2"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
<td>
<asp:LinkButton runat="server" ID="SortByEmailButton"
CommandName="Sort" Text="Email Address"
CommandArgument="EmailAddress" />
<asp:Image runat="server" ID="SortImage3"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
<Fields>
<asp:NextPreviousPagerField
ShowFirstPageButton="true" ShowLastPageButton="true"
FirstPageText="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</Fields>
</asp:DataPager>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<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>
<AlternatingItemTemplate>
<tr class="alternatingItem" runat="server">
<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>
</AlternatingItemTemplate>
</asp:ListView>
<!-- 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" >
</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>
Sub ContactsListView_Sorting(ByVal sender As Object, ByVal e As ListViewSortEventArgs)
' Check the sort direction to set the image URL accordingly.
Dim imgUrl As String
If e.SortDirection = SortDirection.Ascending Then
imgUrl = "~/images/ascending.gif"
Else
imgUrl = "~/images/descending.gif"
End If
' Check which field is being sorted
' to set the visibility of the image controls.
Dim sortImage1 As Image = CType(ContactsListView.FindControl("SortImage1"), Image)
Dim sortImage2 As Image = CType(ContactsListView.FindControl("SortImage2"), Image)
Dim sortImage3 As Image = CType(ContactsListView.FindControl("SortImage3"), Image)
Select Case e.SortExpression
Case "FirstName"
sortImage1.Visible = True
sortImage1.ImageUrl = imgUrl
sortImage2.Visible = False
sortImage3.Visible = False
Case "LastName"
sortImage1.Visible = False
sortImage2.Visible = True
sortImage2.ImageUrl = imgUrl
sortImage3.Visible = False
Case "EmailAddress"
sortImage1.Visible = False
sortImage2.Visible = False
sortImage3.Visible = True
sortImage3.ImageUrl = imgUrl
End Select
End Sub
'</Snippet2>
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView Sorting Example</title>
<style type="text/css">
body { font: 10pt Trebuchet MS, Arial, Tahoma; }
td { border: 1px solid #E6E6FA; }
.header { background: #B0C4DE; }
.alternatingItem { background: #edf5fd; }
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView Sorting Example</h3>
<asp:ListView ID="ContactsListView"
DataSourceID="ContactsDataSource"
OnSorting="ContactsListView_Sorting"
runat="server">
<LayoutTemplate>
<table width="640px" runat="server" id="tblContacts">
<tr class="header" align="center" runat="server">
<td>
<asp:LinkButton runat="server" ID="SortByFirstNameButton"
CommandName="Sort" Text="First Name"
CommandArgument="FirstName"/>
<asp:Image runat="server" ID="SortImage1"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
<td>
<asp:LinkButton runat="server" ID="SortByLastNameButton"
CommandName="Sort" Text="Last Name"
CommandArgument="LastName" />
<asp:Image runat="server" ID="SortImage2"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
<td>
<asp:LinkButton runat="server" ID="SortByEmailButton"
CommandName="Sort" Text="Email Address"
CommandArgument="EmailAddress" />
<asp:Image runat="server" ID="SortImage3"
ImageUrl="~/images/ascending.gif" Visible="false" />
</td>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
<asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
<Fields>
<asp:NextPreviousPagerField
ShowFirstPageButton="true" ShowLastPageButton="true"
FirstPageText="|<< " LastPageText=" >>|"
NextPageText=" > " PreviousPageText=" < " />
</Fields>
</asp:DataPager>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<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>
<AlternatingItemTemplate>
<tr class="alternatingItem" runat="server">
<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>
</AlternatingItemTemplate>
</asp:ListView>
<!-- 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" >
</asp:SqlDataSource>
</form>
</body>
</html>
Remarks
The Sorting event is raised when a Sort button is clicked or the Sort method is called, but before the ListView control handles the sort operation. (A Sort button is a button control whose CommandName property is set to "Sort".) This enables you to perform a custom routine whenever this event occurs, such as customizing the sort expression.
A ListViewSortEventArgs object is passed to the event handler, which enables you to determine the sort expression for the column. It also lets you indicate that the sort operation should be canceled. To cancel the sort operation, set the Cancel property of the ListViewSortEventArgs object to true.
For more information about how to handle events, see Handling and Raising Events.
Applies to
See also
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