Intersoft Community - InitializeDataSource

How to sort WebGrid by displayed text instead of underlying data?

Eric — Tue, 28 Aug 2012 06:28:28 GMT

See this thread for code example:

http://www.intersoftpt.com/Community/WebGrid/WebGrid-How-to-access-Session-object-in-InitializeRow-event-handler/

There's a sorting problem. When sorting by this Name field, it will get sorted by the value in the DataTable from InitializeDataSource, field List_Name. But in InitializeRow I set the ListName.Text (e.Row.Cells.GetNamedItem("xx").Text) to the value that will be displayed. In the case of this example I prepend just "-DIR-" for folders and "-FIL-" for leaf-nodes. When sorting, it won't get sorted by the displayed text, but by the underlying data field (before updating). For this example, the root-level entry "-FIL-a-" comes before "-DIR-b-", just because "a" comes before "b", but the final text is ignored ("-D.." would come before "-F..").

How can I make sure the list gets sorted by the displayed text? Would I have to implement CustomSort event? How?

How to enable / disable freezing depending on data

Eric — Fri, 03 Sep 2010 09:41:51 GMT

There is a related sample in this thread: http://www.intersoftpt.com/Community/WebGrid/WebGrid-crash-scrolling-freeze-column-hidden/

When I have no data for the grid, I want to hide all columns, create my own dataset add a row and write the text "no data" into this first row's first column. This is done in the InitializeDataSource event.

In PreRender event I check if there is only this one row with this special text. If yes, I hide all columns (now works after you fixed the crash mentioned in the other thread).

Problem is now that I cannot dynamically enable/disable the column freezing. For normal display, I want the first column to freeze (not modifiable by user). But when I hide all columns when no data is present, I get the error message "Freeze Pane cannot be activated on this column because it has exceeded the maximum size of scrollable viewport."

I assume this is because there is nothing to show (message is probably slightly wrong). So I should disable the frozen columns in the PreRender event somehow. I couldn't get that working. Or leave freezing away in aspx page and enable it for normal data.

In grid's LayoutSettings I have:

<FreezePaneSettings AbsoluteScrolling="true" ActiveFrozenColumns="1" MaxFrozenColumns="1" ShowSplitterLine="False" /> In PreRender I tried to disable these values without success. I also tried leaving the above tag away and adding these values in PreRender.

I also tried to set/change the value grdResult.LayoutSettings.AllowColumnFreezing. But that caused WebGrid to crash in some JavaScript.

How do I disable/enable column freezing depending on the data I have?

Sample for WebGrid tree view wanted

Eric — Wed, 01 Sep 2010 05:42:24 GMT

Hi,

I need a sample for a simple tree-view using WebGrid version 6.0.7200.218.

It should use the event InitializeSelfReferenceDataSource to load the next node level data. And InitializeDataSource should load the root node data. And the columns are created in the code, not hardcoded in aspx page.

I think I have everything correct (too big to post here), but I just don't get the "plus" image to expand a node. How does WebGrid know if it needs to draw this plus image? What might be missing?

In any case such a sample would be great. I found the samples that use EnableLoadOnDemand (not supported in mentioned version) and the found samples mostly use data connectors in the aspx file, instead of creating the data in InitializeDataSource.

Thanks

WebGrid crashes when scrolling with column freeze and setting a column hidden

Eric — Fri, 08 Jan 2010 08:43:18 GMT

I experience that WebGrid crashes, when the user horizontally scrolls. This happens only when I set the first column to be frozen. It also only happens when I set some columns to hidden (Visible=false).

Attached is a simple sample in VB.NET for that (remove the .txt in the file names). Simplified, the sample contains:

An aspx file with the WebGrid "grdResult" and the columns "Description", "X1", "X2",..."X9"
<FreezePaneSettings AbsoluteScrolling="true" ActiveFrozenColumns="1" MaxFrozenColumns="1" ShowSplitterLine="False" />
In the aspx.vb code file there is a handler for InitializeDataSource which adds some static data to show, so that the grid is not empty
In the handler PreRender I change some column titles (from X1 to C1 etc.) and set two columns to Visible=False

When scrolling, it crashes with: "Microsoft JScript runtime error: 'parentElement' is null or not an object" (Break/Continue/Ignore). The debugger then stands on this JScript code: "var v1d119 =vfcb75.parentElement" (and vfcb75 is null).

I believe this is a bug in WebGrid. We are using the newest WebGrid 6.0.7200.218 and Framework 3.0.5000.705 and the users use Internet Explorer 6 to browse the page.

Can you confirm that this is a bug? If yes, will there be a hotfix available soon? Is there any workaround except not to use freezing or hiding?