Hi Handy,

Thanks for your new sample. At first sight it seems to fulfill the requirements of the original sample.

But after a closer look I saw that you implemented code in the InitializeColumn event for both grids. There you set the width of the first column according to the selected dropdown value. This is not possible.

The value of the dropdown may only be used to pass it to the database when getting the data. What you are doing here is actually hardcoding the database result. If I would have to implement it this way, I would need a second database call in both InitializeColumn events. As mentioned, the database call takes 30 seconds or longer. If I add unnecessary database calls at other places again, this will greatly reduce performance to make the page unusable.

Therefore we need to cache the database result somewhere until we set the column width. What you try to do here (set the width in InitializeColumn) is probably not possible, because at the time where the column gets initialized, we didn't call the database (InitializeDataSource event) yet. So I still think we have to make several changes to get this working. Any ideas on how to resolve this?

Regards,

Eric

To reformulate my initial query, what I need is a sample with the following requirements:

• dropdown for a filter selection for 1-2 webgrids below, aside with a Refresh button, which updates the content of the webgrids below
  
• When changing the dropdown selection, the webgrids should immediately dissappear or be optically visible as invalid, even when the usual refresh takes much longer. Loading the data for the second (or the only) grid takes about 30 seconds from the database.
  
• When the Webgrid contains no rows, it should be displayed somehow. Preferably by inserting a single row, expanding the first column to the whole screen width (and all other columns hidden). As soon as there is data in the grid, the width should be reset to default width.
• In case of two WebGrids, when selecting a row in the first grid, the second grid should update its content. This grid should also show the functionality mentioned above with the "no data"
• When changing the filter dropdown, the header (caption) values of the columns must change, depending on the selected dropdown value (in case of two grids for both).
• For the two-grid scenario selecting the "no data" row in the first grid must not update the second grid. And if nothing is selected in the first grid, the second grid must display "no data".
• In the second (or only) grid a slider for paging must be visible and working.
  

If you find any way to implement all these features, I'll go that way and forget about what I initially wrote.

Thanks,

Eric

Hi Handy,

In my original samples this was all working, but because I didn't pay attention to this, it was set up in a way that you can easily overlook it. Here is how to see this functionality in my original sample:

- The "set both grids invisible" when the dropdown changes (until the user presses Refresh button) was fully functional. Please look again.

- The feature to change the column with of the first column to full width was implemented. But because I changed the columns, the description column was not the first column anymore. In grdUpper_Init and grdLower_Init, please move the AddGridColumn call for the Description to the beginning. Otherwise other columns will be first and in SetColumnVisibility the first code line will not detect the text (it checks tbl.Rows(0).Cells(0).Value).

- The feature to change the column captions was functional. It changes everything with XXX to the value of the currently selected dropdown. But no caption was XXX, so you couldn't see it. In grdUpper_Init and grdLower_Init please change in the call to AddGridColumn the fourth parameter from "A" to "A-XXX" and the same for all three others. (AddGridColumn(grdUpper, "A", "A", "A", ... to AddGridColumn(grdUpper, "A", "A", "A-XXX", ... and the same for A, B, C, D).

I hope you can see that this was working previously. But sorry, that I didn't mention this explicitely. If you can help getting my initial sample working without losing any functionality but removing the crash with the disappearing columns, it would be great.

And do you have any feedback from the developers related to the slider problem already?

Thanks,

Eric

Hi Handy,

Your proposed change to move all code which was in SetColumnVisibility, SetColumnCaptions and column generation into PrepareDataBinding event has another unwanted side effect: The code in SetColumnVisibility doesn't work anymore.

The problem is that first the event InitializeDataSource is being called. In this event, if there is no data, one row with the text "No data available" will be filled into the grid. In SetColumnVisibility this will be detected if number of rows is one and the strings do match. (Not the best method though.)

Now before SetColumnVisibility gets called, all columns are removed and recreated. This has the effect that when the code in SetColumnVisibility accesses the grid, there is no data in the first cell.

So by moving the code into PrepareDataBinding we now have already two unwanted side effects (empty grid detection doesn't work anymore and the column resizing problem). I think this moving wasn't the best idea.

Either we need to fix all occurring side-effects of this change or we have to find another solution to fix the initial problem (disappearing columns yielding to a crash).

Also the non-working slider issue is still open, not sure if this is related or not.

Regards,

Eric

Hi Handy,

I agree that the width problem is a minor issue. But it still needs to be addressed. When the columns get created (now in PrepareDataBinding) I have to give them a width. So if the user changes the width, how should this remain if the columns get recreated in every PrepareDataBinding? I don't see a way to achieve this by still using PrepareDataBinding the way you recommended.

I don't understand what you mean with the FlyPostBackSettings. I stepped through the whole code without this change and cannot see anywhere an access to the dropdown returning an 'ND' (when it's on a different setting). Can you explain this in more detail?

For the other problems, I'm still working on creating more samples for you.

Did you get any feedback for the slider bug already? I'm not sure if I will be able to create a smaller sample, but in case I do, I'll let you know.

Regards,

Eric