[RESOLVED] Dynamic button text changes

[lleemon]

I have a page that I create 5 sections dynamically each with a
1) textbox
2) button
3) label.

If I enter text into say textbox 2 and hit button 2 the label 2 is populated correct. Then if I click any button the last button I pushed will change it's text to what was entered into the last populated label.

Any thoughts on how I stop this from doing that?

Thanks.

<asp:placeholder id="plhContest" Runat="server"></asp:placeholder>

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        Dim intCnt As Integer

        If Not IsPostBack Then
            For intCnt = 1 To 5
                AddContest(intCnt)
            Next
        Else
            For intCnt = 1 To 5
                AddContest(intCnt)
            Next
        End If
    End Sub

    Sub AddContest(ByVal sContestNum As String)
        Dim litLabel As LiteralControl
        Dim txtTextBox As TextBox
        Dim btnButton As Button
        Dim lblOutput As Label

        'Add Literal Control
        litLabel = New LiteralControl()
        litLabel.Text = "<strong>Contest " & sContestNum & ":</strong>"
        plhContest.Controls.Add(litLabel)

        'Add Textbox Control
        txtTextBox = New TextBox()
        txtTextBox.ID = "txtContest" & sContestNum
        plhContest.Controls.Add(txtTextBox)

        'Add Button Control
        btnButton = New Button()
        btnButton.ID = "btnButton" & sContestNum
        btnButton.Text = "Check Contest"
        AddHandler btnButton.Click, AddressOf btnCheckContest_Click
        plhContest.Controls.Add(btnButton)


        litLabel.Text = "<br>"
        plhContest.Controls.Add(litLabel)

        lblOutput = New Label()
        lblOutput.Text = ""
        lblOutput.ID = "lblContest" & sContestNum
        plhContest.Controls.Add(lblOutput)

        litLabel.Text = "<br><br>"
        plhContest.Controls.Add(litLabel)

    End Sub

    Protected Sub btnCheckContest_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim sButton As String = CType(sender, Button).ID
        Dim sButtonID As String
        sButtonID = sButton.Replace("btnButton", "")

        Dim lbl As Label
        lbl = CType(Page.FindControl("lblContest" & sButtonID), Label)
        Dim txt As TextBox
        txt = CType(Page.FindControl("txtContest" & sButtonID), TextBox)

        lbl.Text = "Value entered was:" & txt.Text
    End Sub

[gep13]

Hey,

Have you tried stepping through the code in the debugger? Set a couple breakpoints, and follow the code through. This should help you figure out what is going on.

Gary

[lleemon]

Greg - Yes I did. It doesn't change in AddContest routine or the btnCheckContest_Click routine. Clueless.

[mendhak]

Am I understanding this right?

You click Button2 and Label2 gets the text "2".
You then click Button 4 and then Button2 gets the text "2"?

[lleemon]

mendhak - That is correct.

The proper label always get populated but the last button text changes after the first click.

[lleemon]

I thought I would provide a few screenshots to illustrate what is happening.

1) After I enter text and click the corresponding button.


2) Now I enter text in the 3rd textbox down and click the corresponding button and it populates the corresponding label properly but the first button changes it's text as shown below:

[gep13]

Hey,

I have just taken the code that you provided, and I have been able to replicate the issue that you are having, but at this point I can't offer a reason why it is happening, and how you would go about fixing it?!?

I suspect it has something to do with the fact that you are generating the controls each time the page is created, but I haven't really got enough time to look into it just now.

What is the reason that you are dynamically creating the controls?

Gary

[lleemon]

Hi Gary,

I am creating a quiz/contest type page where we will provide X contests stored in a database and on submit compares to answer and then provides points.

Is there a better way to do this?

Thanks for the time.

[mendhak]

Fascinating. I had a look as well, and the 'change' happens right between these two lines of code:

        plhContest.Controls.Add(btnButton)


        litLabel.Text = "<br>"

So it's right after it's added to the controls collection that it appears that the viewstate for the previous label gets assigned. I suspect that this has something to do with the order in which the items were added to the viewstate on the page. I'm also currently trying to deserialize the viewstate to take a look but VS 2010 keeps crashing. Mysteriouser!

[rjv_rnjn]

lleemon/Mendhak/Gary: did you guys ever figure out what was going wrong or how to fix it? I couldn't make head or tail of this situation and in the process read 2-3 ViewState related articles multiple times.

[mendhak]

Nope, nothing here. Maybe this should be submitted to MS Connect.

[gep13]

Nope, I remember the issue well, but I couldn't for the life of me figure out what was going on.

Gary

[rjv_rnjn]

Shouldn't MVP's be reporting such things without delay..
Hey Mendhak, if you can please do that (I am not sure how MS Connect works) and let us know if they get back with any reason for it or solution.

[mendhak]

Hmm, I just tried to recreate the bug (but in C#), I got this:

        protected void Page_Load(object sender, EventArgs e)
        {
            int count;
            for (count = 1; count <= 5; count++)
            {
                AddContest(count);
            }
        }

        private void AddContest(int count)
        {
            Literal lit = new Literal();
            TextBox txt1 = new TextBox();
            Button btn1 = new Button();
            Label lbl = new Label();
            Label output = new Label();

            lit.Text = "<strong>Contest " + count.ToString() + ":</strong>";
            plhContest.Controls.Add(lit);

            txt1.ID = "txtContest" + count.ToString();
            plhContest.Controls.Add(txt1);

            btn1.ID = "btnButton" + count.ToString();
            btn1.Text = "Check Contest";
            btn1.Click += new EventHandler(btn1_Click);
            plhContest.Controls.Add(btn1);

            lbl.Text = "<br />";
            plhContest.Controls.Add(lbl);

            output.Text = String.Empty;
            output.ID = "lblContest" + count.ToString();
            plhContest.Controls.Add(output);

            lbl.Text = "<br />";
            plhContest.Controls.Add(lbl);

       

        }

        void btn1_Click(object sender, EventArgs e)
        {
 

            string buttonId = ((Button)sender).ID;
            string id = buttonId.Replace("btnButton", String.Empty);

            Label lbl = Page.FindControl("lblContest" + id) as Label;
            TextBox txt = Page.FindControl("txtContest" + id) as TextBox;

            lbl.Text = "Value entered was: " + txt.Text;


        }

And the bug didn't show itself. I wonder...

[mendhak]

Now in VB, the bug doesn't happen anymore.

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        Dim intCnt As Integer
        For intCnt = 1 To 5
            AddContest(intCnt)
        Next
 
    End Sub
 
    Sub AddContest(ByVal sContestNum As String)
        Dim litLabel As New Literal()
        Dim txtTextBox As New TextBox()
        Dim btnButton As New Button()
        Dim lblOutput As New Label()
        Dim lbl As New Label()
 
 
 
        'Add Literal Control
        litLabel.Text = "<strong>Contest " & sContestNum & ":</strong>"
        plhContest.Controls.Add(litLabel)
 
        'Add Textbox Control
        txtTextBox.ID = "txtContest" & sContestNum
        plhContest.Controls.Add(txtTextBox)
 
        'Add Button Control
        btnButton.ID = "btnButton" & sContestNum
        btnButton.Text = "Check Contest"
        AddHandler btnButton.Click, AddressOf btnCheckContest_Click
        plhContest.Controls.Add(btnButton)
 
 
        lbl.Text = "<br>"
        plhContest.Controls.Add(lbl)
 
        lblOutput.Text = ""
        lblOutput.ID = "lblContest" & sContestNum
        plhContest.Controls.Add(lblOutput)
 
        lbl.Text = "<br><br>"
        plhContest.Controls.Add(lbl)
 
    End Sub
 
    Protected Sub btnCheckContest_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim sButton As String = CType(sender, Button).ID
        Dim sButtonID As String
        sButtonID = sButton.Replace("btnButton", "")
 
        Dim lbl As Label
        lbl = CType(Page.FindControl("lblContest" & sButtonID), Label)
        Dim txt As TextBox
        txt = CType(Page.FindControl("txtContest" & sButtonID), TextBox)
 
        lbl.Text = "Value entered was:" & txt.Text
    End Sub

The difference here is that as I habitually started cleaning up, I made new labels for the "<br>" instead of reusing it. Might that be it?

[gep13]

Interesting, when I found it the first time, I didn't bother cleaning up the code, I just did a blind copy of the data.

That is very interesting!!

Gary

[mendhak]

The bugs were... literally... lost in translation!

[gep13]

Oh my word, where do you get these

[lleemon]

Thanks guys for spending your time on this. Hope it helps others.

Dynamic controls seem a little touchy. Do a lot of people not use because of this?

[mendhak]

As much as possible, developers tend to use the controls such as repeaters/gridviews which do a lot of viewstate maintenance for you. It's only sometimes that you'd have to use dynamic controls to accomplish a certain task, but yes, people do use it without problems. You just got unlucky.

[gep13]

Thanks guys for spending your time on this. Hope it helps others.

Dynamic controls seem a little touchy. Do a lot of people not use because of this?

Hey,

I think I have had to use Dynamic Controls once, I have been able to do everything else using the built in controls.

Gary

[rjv_rnjn]

Wow! Great find. And I thought it's ViewState.

eDIT: And why should I "spread some Reputation around before giving it to mendhak again."? I don't remember that happening. A Session issue this time?

[gep13]

Hey,

Forum rules says that you can't simply keep giving reputation to the same person over and over again. This could lead to some people abusing the system by rep'ing each other all the time.

If I remember correctly, you have to rep 10 other people, before you can give rep to the same person again.

Gary