Hi,
This is a newbie question. I Am doing some performance tests on the grid.
I Have a XAMDataGrid bound to an observable collection of my custom class objects.
In my data class I have some static properties and I am also dynamically adding some properties using the ICustomTypeDescriptor interface.
The problem I Have is that the grid is only showing the static columns, and not the dynamically added ones. I tried handing the FieldInitialisd events and adding the custom columns manually, but I Am not able to get them to bind properly.
So my question is how do I get the grid to bind to dynamic columns added via the CustomTypeDescriptors?
Appreciate any help,
thanks
BIjesh
Alex,
Any changes in ICustomTypeDescriptor support for xamDatagrid since this answer was posted?
Any plans to support?
Regards,
Sergei.
Hi Alex,
Thank you for the confirmation. Yes I will try to implement this in DataTable for testing larger number of columns. My concern with this initially was that DataTAbles may not be very efficient and so may not accurately reflect the Grid's performance, but hopefully .NET 3.0 DataTAbles are more efficient than the 2.0 one.
thanks and regards
Bijesh
Bijesh,
The development updated me. We do not support ICustomTypeDescriptor with the XamDataGrid, as the properties are retrieved based on the type and not on the instance of the object. One way for achieving this effect is to implement ITypedList (so that the XamDataGrid will make a query for the properties) and IBindingList ( so that the ListChanged event will fire as notification when adding/removing properties). This is basically the mechanism how datatable works, so you can try binding the XamDataGrid to a DataTable and add/remove columns if that is possible in your scenario.
Thanks. I will try this out. But please do get back to me when you get an update from the dev team, as I am not sure whether this way will really test a scenario where the data itself has around 100 columns.
Also I've noticed that if I set the columns in XAML I can't then change the collection object that it is bound to at runtime as it throws an exception:"Can't set the DataSource on a DataPresenter that has items added explicitly through the DataItems collection." Is this by design?
Anyway I will try to set the fieldlayout programattically, but do let me know if it is possible to use custom type descriptors..
Thanks for clearing that out. I am not really sure why these changes are not reflected by the XamDataGrid and I have brought that up to the development team. Until I get an update from them, you can use UnboundFields and set their BindingPath to an already existing property of the underlying class (which I am assuming you are using, rather than DataTable, in which case is pretty straightforward).
like:
<igDP:Field Name="Column1" />
<igDP:UnboundField Name="Column1" BindingPath="Column1"/>
<igDP:Field Name="Column2" />
<igDP:Field Name="Column3" />
<igDP:Field Name="Column4" />