WPF DataGrid：获取列绑定属性以进行过滤

Question

I am trying to develop a filtering functionality for WPF DataGrid (from the WPF Toolkit). I want a user to right-click any cell and select Filter from its CcontextMenu , and then the grid should be filtered by the cell's value.

I am trying the MV-VM pattern. My windows's datacontext is MainWindowViewModel which has a property Transactions . This property returns ObservableCollection<TransactionViewModel> , and the data grid uses this collection as its items source. So basically each row is bounded to TransactionViewModel (as you can guess, this grid lists transactions). MainWindowsViewModel has ICollectionView which is used for filtering and tracking the currently selected row. The DataGrid has its property IsSynchronizedWithCurrentItem set to "true", so myCollectionView.CurrentItem gives me the currently selected TransactionViewModel .

The only thing I still need to know is by which column I need to filter. This depends on where the user clicked the context menu. So I am trying to pass this information using CommandProperty of the context menu item. And here I have a real problem. I tried this:

CommandParameter="{Binding Column.Binding.Path.Path, 
                                       RelativeSource={RelativeSource FindAncestor,
                                                       AncestorType={x:Type tk:DataGridCell}}}" />

This is really ugly, but this works for DataGridTextColumn s. Unfortunately, I have also DataGridTemplateColumn s, and they don't work (the path is different there, because I need to reach the actual cell template)...

So how can I implement this functionality? Perhaps the whole way is wrong? I didn't find any valuable example on that. The only thing I found is the WPF DataGrid autofilter implementation on the Codeproject which doesn't work at all for some reason...

Thank you.

Answer 1

I'm not 100% sure if this would help but...

DataGrid has CurrentCell so you could bind it in TwoWay mode in your MainWindowViewModel. Then every "row" could point to DoFilter command defined in MainWindowViewModel. It's not a beauty solution (because viewmodel has to know DataGrid Cell type) but it should work.

Answer 2

Why not just pass the cell as a parameter like this:

CommandParameter=
  "{Binding RelativeSource={RelativeSource FindAncestor,tk:DataGridCell,1}}" />

and let your command's Executed event handle all the hard part of finding the actual column name? That way you can write all the special-case code you need.