SelectedIndexChanged RESOLVED

[joef]

Hi

I have a function "Private Sub fillBoxes(ByVal recordPos As Integer)" which fills several text boxes in the page with the contents of a database table row. RecordPos is the number of the row in the table.

I can call this function in the pageload with fillBoxes(0), or fillBoxes(4) or whatever and it works fine. However, I am trying to call it from the SelectedIndexChanged event of a DropDownList, like this:

Private Sub ddlKey_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlKey.SelectedIndexChanged
fillBoxes(ddlKey.SelectedIndex)
End Sub

So basically the user selects a value from the list and the textboxes are filled with the corresponding data row. This throws an exception, however, saying "There is no row at position X". There is nothing wrong with the function as it works fine when I call it in the page load.

Any ideas what could be wrong?

Thanks
Joe

[mendhak]

Set a breakpoint on that line of code. What value does SelectedIndex hold?

[joef]

Thanks for the reply. I set the breakpoint, and selected the fourth item on from the DropDownList. Since it is zero-based, the value of SelectedIndex should be 3, and it is. Since there are 30-odd records in the database table, 3 should be fine, in theory...?

[mendhak]

Yes it should. Now go F11, into the function you made. Try following it until you get to the dataset's call based upon that index.

Try setting a quickwatch on the dataset too.

[joef]

Ok now this is weird. The function looks like this:

Private Sub fillBoxes(ByVal recordPos As Integer)
txtDesc.Text = DsAll1.HDSLMT(recordPos).DESCRIPTION

txtChoice1.Text = DsAll1.HDSLMT(recordPos).VALCHAR_1
txtChoice2.Text = DsAll1.HDSLMT(recordPos).VALCHAR_2
etc...
...
txtChoice9.Text = DsAll1.HDSLMT(recordPos).VALCHAR_9

txtDesc1.Text = DsAll1.HDSLMT(recordPos).VALTXT_1
txtDesc2.Text = DsAll1.HDSLMT(recordPos).VALTXT_2
etc...
...
txtDesc9.Text = DsAll1.HDSLMT(recordPos).VALTXT_9
End Sub

But none of those lines actually throw the exception. The exception is thrown at line 406, which is in a button click event handler, and that button hasn't even been clicked?!

I'm not a very experienced programmer and maybe I'm talking rubbish but to me that doesn't make sense.

[mendhak]

And you used F11 to break in?

[joef]

In my understanding F11 is just a shortcut for start program.

[mendhak]

Um... no, when you reach the line which calls the function you wrote, F11 will break into that function so you can follow the values being passed.

[joef]

I feel like I'm being really stupid here and just wasting your time. Sorry. This is a web application. I definitely should have said that at the start. All F11 does is alter the size of the browser window.

[nana_81]

by the way F8 will break into that function in my PC. so my advice is to double check

[joef]

Ahh, it's all clicked now

I'll see what I can find by this method.

[joef]

Yep, I've fixed the problem now. Thanks a lot guys.

[mendhak]

Add [Resolved] to the thread title. And perhaps tell us what the problem was.

[joef]

Ok, have done.

The problem was that immediately before calling the function, I needed to refill the dataset with the dataadapter. Otherwise, for some still unknown reason, it lost its records when the SelectedIndexChanged event occured.