[RESOLVED] Help with check boxes in a repeater

[Ameera]

Hi

I am trying to use a check box within a repeater in an asp.net vb application. Basically, i am have an application that allows users to create blog posts and then other users can comment on them. I am using a check box to provide the user with functionality to like the posts comments.

When the user clicks on like, it is supposed to fire the event which will insert or update the users like record. However, this even does not seem to be firing.

i set up the check box within a table within the repeater as follows:

                                                <td class = "LikeCellRepeat">
                                                    Like: <asp:CheckBox ID="chkLikeComment" 
                                                    runat="server" 
                                                    ToolTip="Like" 
                                                    AutoPostBack="True"
                                                    OnCheckedChanged="chkLikeComment_CheckedChanged"/>                                                    
                                                    <asp:ToggleButtonExtender ID="Toggle_chkLikeComment" runat="server" 
                                                    Enabled="True" 
                                                    TargetControlID="chkLikeComment" 
                                                    CheckedImageAlternateText="Liked" 
                                                    CheckedImageUrl="~/Images/Liked.png" 
                                                    UncheckedImageUrl="~/Images/Unselected.png" 
                                                    ImageHeight="19" 
                                                    ImageWidth="19">
                                                    </asp:ToggleButtonExtender>                                                        
                                                </td>

and here is the check changed event:

    Protected Sub chkLikeComment_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        MsgBox("like clicked")
        Dim CommentItem As RepeaterItem = sender.NamingContainer
        Dim HiddenID As HiddenField = CType(CommentItem.FindControl("HiddenCommentID"), HiddenField)
        Dim CommentID As Integer = Convert.ToInt32(HiddenID.Value)

        Dim isCommentLiked As Boolean = ExistingCommentLike(CommentID)
        Dim isCommentDisliked As Boolean = ExistingCommentDislike(CommentID)

        If (isCommentLiked = False And isCommentDisliked = False) Then
            'user did not previously like or dislike comment, so insert record'
            AddUserCommentLike(DirectCast(sender, CheckBox).Checked, CommentID)
        Else
            'user previously liked or disliked comment, so update record'
            UpdateUserCommentLike(DirectCast(sender, CheckBox).Checked, CommentID)
        End If

        'Display how many likes and dislikes there are on this comment'
        DisplayCommentLikesAndDislikes()

    End Sub

i included a Msgbox in the event to see if i would at least get that and then the problem might be something else, but i don't even get the msgbox to pop up which is why i'm thinking the check changed event is not even firing.

I've been searching the net for solutions on how to get it to fire, but what i've found so far either does not work or i am not using it properly. I saw something about re-subscribing to the event in repeater's on item data bound, and tried to set up that the way they had, but i am not sure if i did it right, as i get an error that says the checkedchanged cannot be called directly and to use raise event instead...

    Protected Sub rptComments_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles rptComments.ItemDataBound
        Dim CheckLike As CheckBox = CType(e.Item.FindControl("chkLikeComment"), CheckBox)
        CheckLike.AutoPostBack = True

        CheckLike.CheckedChanged += New EventHandler(chkLikeComment_CheckedChanged)
    End Sub

I have been trying to get this to work for about a week now with no luck. Would appreciate any help i can get...

Thanks!

[gep13]

Hello,

Since this question is about ASP.NET, I am going to move it to the ASP.NET Forum.

Gary

[gep13]

Hello Ameera,

Welcome to the forums!!

When you are posting code into the forum, can you please remember to surround it in [code][/code] or [highlight][/highlight] tags? It makes it a lot easier to read. I have done this for you in your above post.

Gary

[gep13]

Hello Ameera,

A couple of questions..

Are you testing this application by deploying it onto a Web Server, or are you running directly out of Visual Studio?

The reason that I ask is two fold...

If you are running directly out of Visual Studio, setting a breakpoint on the line of code that you are interested in, is a much easier and simpler way to test the code execution path, rather than using a MsgBox.

Secondly, if you are running the site deployed to a Web Server, then you are never going to see the MsgBox. It runs in the same process as the application is running, so you are never going to see it on the client machine.

Gary

[Ameera]

Hi Gary

Thanks...

I am running the app out of visual studio.

I tried using the break point by placing it within the chek change event but nothing happens. I am assuming maybe because the check event is not even firing within the repeater?

Should i try placing the break point elsewhere? Not sure where though..

Regards

Ameera

[Lightning]

You need to re-subscribe to the events in every pageload for every dynamic created control

[Ameera]

You need to re-subscribe to the events in every pageload for every dynamic created control

Thanks. i saw that while searching for help online but i am not sure how to do that.
This is the code for my page load

 
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Not Page.IsPostBack Then
            GetPostDetails()
            DisplayPostRatings()
            DisplayPostLikesAndDislikes()
        End If
        GetPostComments()
        DisplayCommentRatings()
        DisplayCommentLikesAndDislikes()

    End Sub

the repeater data bind takes place in GetPostComments().

Thanks

Ameera

[gep13]

Hi Gary

Thanks...

I am running the app out of visual studio.

I tried using the break point by placing it within the chek change event but nothing happens. I am assuming maybe because the check event is not even firing within the repeater?

Should i try placing the break point elsewhere? Not sure where though..

Regards

Ameera

Ah, ok, now we are getting somewhere...

In this scenario, you would need to attach Visual Studio "remotely" to the IIS instance in order to have your code stop on a particular breakpoint. This is known as remote debugging.

Here are the setup instructions for Visual Studio 2010:

http://msdn.microsoft.com/en-us/library/bt727f1t.aspx

Gary

[gep13]

You need to re-subscribe to the events in every pageload for every dynamic created control

Unless I am missing something, I don't see a direct need to create the CheckBox dynamically, rather simply set the Checked property of the CheckBox that is already contained within the ItemTemplate.

Gary

[Lightning]

Controls in a repeater are always dynamically created

[Ameera]

Hi

Thanks.. would anyone be able to guide me on resubscribe to the event in the page load? i am seeing this a lot online as the solution to the problem, but i don't know how to do that.

would it be something like:

 ChkLikeComment.CheckedChanged += New EventHandler(chkLikeComment_CheckedChanged)

i tried doing that in the repeater item databound but it was underlined with an error stating that it is an event and cannot be called directly and to use raise event instead..

i also tried doing that in the page load but it does not recognise ChklikeComment becuase it is in the repeater and also underlined (chkLikeComment_CheckedChanged) wiht an error that says

"Delegate 'System.EventHandler' requires an 'AddressOf' expression or lambda expression as the only argument to it's constructor"

i am really lost as to how to get this check box to work within the repeater.. i need to get this done for a school project as soon as possible.... would appreciate any help i can get.

[Lightning]

If you rebind the data in the pre-init event, you can foreach thru the items in the repeater. Using item.FindControl("chkLikeComment") you can get all the "likecommennt checkboxes" and add the eventhandlers

[gep13]

Depending on exactly what you are trying to achieve, simplifying this slightly might be the right approach. Here is one technique which doesn't require an individual event handler, but rather uses a common one:

http://www.codeproject.com/Articles/...ew-or-Repeater

Gary

[gep13]

Controls in a repeater are always dynamically created

Doh! Good point well made

[Ameera]

Depending on exactly what you are trying to achieve, simplifying this slightly might be the right approach. Here is one technique which doesn't require an individual event handler, but rather uses a common one:

http://www.codeproject.com/Articles/...ew-or-Repeater

Gary

Hi

I don't think that will work for me as my problem is not getting the id of the item, but rather getting the change event to fire. I'm actually using the checkbox to indicate if a person likes a blog comment. The blog comments are stored in one table, the likes and dislikes in another. Upon page load, the repeater will display the comments, and will display if the logged in user already likes or dislikes each comment.
Hence some of the checkboxes will already, upon loading, have a status of checked if you've already liked or dislike that comment.
If he has not yet liked or disliked it, it will display as unchecked. i need to track each like by each user.... so everytime the like or dislike checkbox is clicked, it's supposed to check if you've already liked or disliked the comment and if not, insert a new record in the like table with the comment id, your user id and the store the like / dislike accordingly. If you have, it will find your record and update it, based on what you clicked.

So the key thing is that i need it to respond when the users click on it, wheter or not they are now adding a like / dislike or updating thier existing like / dislike. I went in the db and manually created a like entry for a user and it displays correctly when the page is loaded. The problem is just upon clicking on the checkbox... *sigh*

If you can think of a way i can do this, using the methods described in the link you provided, i will be gratefull as it does indeed seem a lot simpler.

[Ameera]

If you rebind the data in the pre-init event, you can foreach thru the items in the repeater. Using item.FindControl("chkLikeComment") you can get all the "likecommennt checkboxes" and add the eventhandlers

Ok, so i tried to set up the pre-init as follows:

    Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit
        rptComments.DataSource = GetPostComments()
        rptComments.DataBind()
        For Each CommentItem As RepeaterItem In rptComments.Items
            Dim CheckLike As CheckBox = CType(CommentItem.FindControl("chkLikeComment"), CheckBox)
            CheckLike.AutoPostBack = True
            CheckLike.CheckedChanged += New EventHandler(chkLikeComment_CheckedChanged)            
        Next

    End Sub

However, the statement

 CheckLike.CheckedChanged += New EventHandler(chkLikeComment_CheckedChanged)

get blue underlined with an error in 2 places

CheckLike.CheckedChanged gets the error stating that it is an event and cannot be called directly and to use raise event instead..

chkLikeComment_CheckedChanged gets the error stating that "Delegate 'System.EventHandler' requires an 'AddressOf' expression or lambda expression as the only argument to it's constructor"

Am i adding the event handlers wrong? Or have i set up the preinit wrong in some way?

[gep13]

Hello,

Did you try the sample that I directed you to in that article?

From a very brief read, it would seem to do exactly what you want.

Gary

[gep13]

Am i adding the event handlers wrong? Or have i set up the preinit wrong in some way?

Hey,

Looks like you are using the C# syntax, rather than the VB.NET Syntax.

Have a look at the documentation here:

http://msdn.microsoft.com/en-us/libr...edchanged.aspx

Gary

[Ameera]

Hi

I am using the AddHandler now and it works!!!! i had to do it in the repeater's on item data bound and then ensure that i bind the data to the repeater in the Is Not post back section of my page load, and it finally fired the event, and i got the Msgbox as well

I can now successfully like or dislike a comment in the repeater thank you so much

Regards

Ameera

[gep13]

Hello,

Glad to hear that you got it working!

For the benefit of other people who might have a similar issue, would it be possible for you to share your final working code?

Also, since your question is now answered, can you go back and mark your thread as resolved?

If you are not sure how to do this, you will find a link in my signature for help with this.

Gary

[Ameera]

Sure, I've marked it as resolved.

i don't mind sharing the final code, but it's school project that i have to pass through a plagiarism detector that searches online. I wouldn't want it to return a positive find on the code, so after i hand up the project on Sep. 10, i'll post the code then.

[gep13]

Not a problem at all.

Thanks for sharing. Hopefully you get a good mark!

Gary