GDBG Internal working

[Administrator]

Correct me if am wrong.. but would definitely like to share this observation...

We are using GDBG binded to a dataset.. this gives a whole suite of cool features out of box filtering, grouping, sorting, row and column freezing etc.. furthermore it decouples the view from the model and programming logic will be driven based on the model without even worrying about nitty-gritties of view such as updating particular row and column index in the grid etc...

i subscribed to PrepareViewStyleInfo event of the GDBG and added the below line

Debug.WriteLine(" Row : " +e.RowIndex +" Col : " +e.ColIndex);

1. What i noticed is preparviewstyleinfo is fired only for the visible rows and columns.. and this is equivalent to Virtual Grid control which does the same thing.. and it is good...

2. the second thing is lets say we have about 1000 rows loaded in GDBG but only 100 row is visible.. user has to scroll to view the rest of the rows... so lets say if i update a column of a row that is not visible in grid view area.. will GDBG update its internal model even though it is not visible...

the final question is lets say if we build a dataset binding behaviour to virtual grid we will no more be able to use all cool features provided by GDBG grid... but i don''t see any gain if point no. 1 and 2 is already handled by GDBG except that there is less tax on memory usage as virtual grid doesn''t hold any state... but we are not concerned about memory at this point...

Thx for your help...

Regards
Yogi

Regards
Yogi

[Administrator]

GridDataBoundGrid is a virtual grid. It has implemented the virtual events in a manner that makes it particularly tailored to be used with a column oriented data source like a DataTable or some IBindingList object. So, yes, it does behave like a virtual grid that uses special knowlegde of the datasource to support things like sorting and filtering out of teh box.

2) If the datasource is updated in a position off the screen, the GridDataBoundGrid actually does nothing. When it happens to need the value from the updated position, it will query the datasource for the required value (as would happen in any virtual grid), and at this point the data source would provide the updated value to the GridDataBoundGrid.