[RESOLVED] Error: cannot obtain value in Watch

[scsfdev]

Hi all,

I'm facing a strange problem in VS.Net 2003 Debugger mode.

I'm testing a window application which was written in VB.Net 2003.
I set a few BreakPoints and Debug the project.
When the debugger hit one of the breakpoints, it stops at there. Its correct.
But when I try to add one of the variables to "Watch", it said "error: cannot obtain value".

I tried to search the Net and found that some said "its because of structures", some said "its because of passing too many parameters." and some said "its because of too many line of codes (LOCs)".

but my problem is not in passing parameters or too many line of code.
the function i set breakpoint has only around 300 LOCs (including around 100 line of comments)

And the value I tried to get is from my TreeView which is on my Win Forms.
its very strange that I can't even get the value from Forms.
I assign this TreeView value to another TreeView (this one is declare in code.)
And this second TreeView also can't view Watch.

What can I do for that?
Any suggestions or any fixes?

I'm using Visual Studio 2003 in VB.Net with SQL Server 2000 for the above project.

Thanks.

[jmcilhinney]

If you are having a problem with some specific code, would it not be a good idea to show us that code?

[scsfdev]

Hi jmcilhinney,
Sorry, I thought it didn't related to my code. So, I didn't put it here.
Here is some of my code.

Private Sub PrintIDCard(ByVal dtCard As DataTable, ByVal LabelType As String, ByVal Category As String)
        Dim iCount As Integer : Dim LabelSize As String : Dim LoopTree As Int16 : Dim LabelID As Integer
 
        For iCount = 0 To dtCard.Rows.Count - 1
            'If CStr(dtCard.Rows(iCount).Item("Label_Type")).ToUpper = LabelType.ToUpper And _
            'CStr(dtCard.Rows(iCount).Item("Category")).ToUpper = Category.ToUpper Then
 
            Dim PrintData As String : Dim StuID As String : Dim CardID As String
            Dim Status As Char
 
            If dtCard.Rows(iCount).Item("LABEL_TYPE").ToString.Equals(LabelType) And dtCard.Rows(iCount).Item("Category").ToString.Equals(Category) Then
                Dim Qty As Integer = 0
          
                If StuID Is Nothing Then
                    StuID = dtCard.Rows(iCount).Item("StuID").ToString
                End If
 
                CardID = dtCard.Rows(iCount).Item("CardID").ToString
 
                Dim getSelected As Boolean = False
 
                If (LabelType.Equals("StuLabel1") Or LabelType.Equals("StuLabel2")) Then
                    Dim SelectedTreeView As TreeView
                    Dim SelectedTreeView2 As TreeView
 
                    If LabelType.Equals("StuLabel1") And Category.Equals("C") Then
                        SelectedTreeView = TreeStu1
                    ElseIf LabelType.Equals("StuLabel2") And Category.Equals("C") Then
                        SelectedTreeView = TreeStu2
                    ElseIf LabelType.Equals("StuLabel1") And Category.Equals("P") Then
                        SelectedTreeView = TreePStu1
                        SelectedTreeView2 = TreePStu2
                    ElseIf LabelType.Equals("StuLabel2") And Category.Equals("P") Then
                        SelectedTreeView = TreePStu3
                        SelectedTreeView2 = TreePStu4
                    End If
 
                    getSelected = getPrintData(SelectedTreeView, CardID, StuID, dtCard.Rows(iCount).Item("SEQ").ToString, Category, SelectedTreeView2)
                    If getSelected = True Then
                        PrintData = ""
                    End If
                Else
                    getSelected = True
                End If
 
                If getSelected = True Then
                    Dim LType As String = ""
                    If LabelType.Equals("LibrLabel") Then
                        LType = "H"
                    ElseIf LabelType.Equals("StuLabel1") Or LabelType.Equals("StuLabel2") Then
                        LType = "C"
                    Else
                        LType = ""
                    End If
 
                    If Format(CDate(dtCard.Rows(iCount).Item("Printed_date")), "yyyy/MM/dd").Equals("1900/01/01") Then
                        'is a new card
                        Status = "N"
                    Else
                        ' this is a reprint card
                        Status = "R"
                    End If
 
               '..... and so on. sorry I can't show up all the code here. Please understand me.
 
        Next iCount
    End Sub

First call from btnPrint_Click to PrintJob Function.
In PrintJob function it will check input data and Load the necessary data.
From PrintJob, it will go to PrintIDCard function by passing the DataTable to it.

I can't get the dataTable value also. It said the same error.
And for same for below two code, it always said can't obtain value error.
SelectedTreeView = TreePStu1
SelectedTreeView2 = TreePStu2

This TreePStu1 and TreePStu2 are my TreeViews. I put these 2 TreeView in Designer. By right, I can get the value of each view.
So strange is I can get the value of each TreeView while I'm in btnPrint_Click and PrintJob functions.

But when I arrived PrintIDCard function it said:
TreePStu1.nodes.count - Expression cannot be evaluated at this time.
TreePStu1 - error: cannot obtain value.

Hope the code I provided is OK with you.

Here is my Print Click function

Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click
        Cursor.Current = Cursors.WaitCursor
        PrintJob()
        Cursor.Current = Cursors.Default
        Me.Close()
    End Sub

Here is the another function (PrintJob)

Private Sub PrintJob()
        Dim StuDS As DataSet
        Dim StuDT As DataTable
        StuDS = GetReprintStudentList(txtStuStart.Text, txtStuEnd.Text)
 
        StuDT = StuDS.Tables(0)
        With DGridList
            .DataSource = StuDS.Tables(1)
            .Refresh()
        End With
 
        If Me.chkPStu1.Checked And chkPStu1.Visible = True Then PrintIDCard(StuDT, "StuLabel1", "P")
        If Me.chkPStu2.Checked And chkPStu2.Visible = True Then PrintIDCard(StuDT, "StuLabel2", "P")
    End Sub

[scsfdev]

Currently, should I say "I'm blind trace and debugging the program!"
Although I can't get the value directly, I can get Nodes Count in-directly.

Dim iNodeCount As Integer = TreePStu1.Nodes.Count

I can get the Nodes count from PrintIDCard function from above code but actually I need is what inside the TreeView's Nodes.
so, now, I just assume this time - value A, next time - value B in TreeNode loop etc.
Although it seems to work now, I'm not sure when the data accuracy will raise issue/error.
So, I'm trying to find a way to get the value in Watch.

I hope i don't need to change the code logic too much. (Since I took over this project, lots of errors to fix and very short time frame to deliver )
If I need to change the way passing parameters or change some array, class or something, etc, I sure gonna have sleepless nights

[jmcilhinney]

It looks like that may be a bug in VS that was never actually fixed in VS.NET 2003.

http://connect.microsoft.com/VisualS...dbackID=237556

[scsfdev]

It looks like that may be a bug in VS that was never actually fixed in VS.NET 2003.

http://connect.microsoft.com/VisualS...dbackID=237556

Hi jmcilhinney,

Thanks for your precious information.
This is my first time I surf that web site. May be later it will surely useful for me.
If not because of ur link, I may digging the Net and my time will tick, tick

So, I only have a chance of blind debug.
Anyway, I may need to put a little extra effort while debugging.
Thanks again.

[jmcilhinney]

Note that I simply Googled your error message, i.e. error: cannot obtain value, and that page was near the top of the results. I'm guessing that you could have done that.

[scsfdev]

Note that I simply Googled your error message, i.e. error: cannot obtain value, and that page was near the top of the results. I'm guessing that you could have done that.

Really???
So strange!
I only found these data
http://www.google.com/search?rlz=1C1...t+obtain+value

Error: Cannot obtain value - SOLUTION

Error: Cannot obtain Metadata

and channel9.msdn.com, forums.asp.net, tech-archive.net, pcreview.co.uk, syncfusion.com, bytes.com, and also this thread too!!!
but not ur link. I think google return the result based on region or based on user activity. I checked up to Page no 1, 2, 3 and 4 in Google and still no such site listed

anyway, i got a new useful link from you!!