The code-behind file for the Blog page in VS .NET

Draw Code 39 in VS .NET The code-behind file for the Blog page

The code-behind file for the Blog page must handle the PageLoad event to determine which post should be displayed In addition, it must handle the click events for the View Comments and Leave a Comment links so it can

set up the query strings passed to the Commentsaspx and Commentaspx page Listings 11-5 and 11-6 show the C# and Visual Basic versions of this code-behind file

Listing 11-5:

The code-behind file for the Blog page (C# version)

System; SystemData; SystemConfiguration; SystemCollections; SystemWeb; SystemWebSecurity; SystemWebUI; SystemWebUIWebControls; SystemWebUIWebControlsWebParts; SystemWebUIHtmlControls;

public partial class Blog : SystemWebUIPage { protected void Page_Load( object sender, EventArgs e) { if (!IsPostBack) { if (RequestQueryString[ post ] == null) GridView1SelectedIndex = 0; else { GridView1SelectedIndex = Int16Parse( RequestQueryString[ post ]); } thisDataBind(); } } protected void btnViewComments_Click( object sender, EventArgs e) { ResponseRedirect( Commentsaspx post= + GridView1SelectedIndexToString() + &postid= + GridView1SelectedValueToString() + &blog= + RequestQueryString[ blog ]); } protected void btnLeaveComment_Click( object sender, EventArgs e) { ResponseRedirect( Commentaspx post= + GridView1SelectedIndexToString() + &postid=

+ GridView1SelectedValueToString() + &blog= + RequestQueryString[ blog ]); } } The following paragraphs describe the three methods in this code-behind file:

The Page_Load method sets the SelectedIndex property of the GridView control to the value indicated by the post query string field, if the post query string is present If the post query string is missing, the SelectedIndex property is set to zero Then the DataBind method is called to bind the controls on the page The btnViewComments_Click method is called when the user clicks the View Comments link It simply redirects the user to the Commentsaspx page, passing query string fields that contain the ID of the selected post (postid), the index of the selected post (post), and the ID of the current blog (blog) The btnLeaveComment_Click method is called when the user clicks the Leave a Comment link It redirects the user to the Commentaspx page, passing the same query string fields as the btnViewComments_Click method

Listing 11-6:

The code-behind file for the Blog page (VB version)

Partial Class Blog Inherits SystemWebUIPage Protected Sub Page_Load( _ 1 ByVal sender As Object, _ ByVal e As SystemEventArgs) _ Handles MeLoad If Not IsPostBack Then If RequestQueryString( post ) Is Nothing Then GridView1SelectedIndex = 0 Else GridView1SelectedIndex _ = Int16Parse( _ RequestQueryString( post )) End If MeDataBind() End If End Sub Protected Sub btnViewComments_Click( _ ByVal sender As Object, _ ByVal e As SystemEventArgs) ResponseRedirect( Commentsaspx post= _

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Listing 11-6 (continued)

+ + + + + End Sub Protected Sub btnLeaveComment_Click( _ ByVal sender As Object, _ ByVal e As SystemEventArgs) _ End Sub End Class GridView1SelectedIndexToString() _ &postid= _ GridView1SelectedValueToString() _ &blog= _ RequestQueryString( blog ))

The Comments page uses a GridView control to display all comments left for a particular post The ID of the post whose comments are to be displayed is passed to the page via a query string field You can refer back to Figure 11-4 for a glimpse of what this page looks like

Listing 11-7 shows the Commentsaspx page As you can see, this page uses three SQL data sources, two FormView controls, and a GridView control to display the comments that have been created for the post

Listing 11-7:

<%@ Page Language= C# MasterPageFile= ~/MasterPagemaster AutoEventWireup= true CodeFile= Commentsaspxcs Inherits= Comments Title= Blog-O-Rama %> <asp:Content ID= Content1 Runat= Server ContentPlaceHolderID= ContentPlaceHolder1 > <asp:FormView ID= FormView2 runat= server DataSourceID= SqlDataSource1 DataKeyNames= postid > <ItemTemplate> <asp:Label ID= lblSubject runat= server Text= <%# Bind( subject , <h1>{0}</h1> ) %> > </asp:Label>

2 3

<asp:Label ID= lblDate runat= server 5 Text= <%# Bind( postdate , <h3>{0:F}</h3> ) %> > </asp:Label> </ItemTemplate> </asp:FormView> <asp:SqlDataSource ID= SqlDataSource1 6 runat= server ConnectionString = <%$ ConnectionStrings:BlogConnectionString %> SelectCommand= SELECT [postid], [blogid], [postdate], [subject] FROM [Posts] WHERE ([postid] = @postid) > <SelectParameters> <asp:QueryStringParameter 7 Name= postid QueryStringField= post Type=Int32 /> </SelectParameters> </asp:SqlDataSource> <br /> <asp:DataList ID= DataList1 runat= server 8 DataSourceID= SqlDataSource2 > <ItemTemplate> <hr> <asp:Label ID= lblUserName 9 runat= server Text= <%# Bind( username , Comment by {0} ) %> Font-Size= X-Small /> <asp:Label ID= lblDate runat= server 10 Text= <%# Bind( commentdate , Date: {0:G} ) %> Font-Size= X-Small /> <br /> <asp:Label ID= lblComment 11 runat= server Text= <%# Bind( comment ) %> Width= 300px /> </ItemTemplate> </asp:DataList> <asp:SqlDataSource ID= SqlDataSource2 12 runat= server ConnectionString = <%$ ConnectionStrings:BlogConnectionString %> SelectCommand= SELECT [commentdate], [username], [comment] FROM [Comments] WHERE ([postid] = @postid) ORDER BY [commentdate] > <SelectParameters>

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