MVVM WPF datagrid data entry problem

I have a datagrid in my MVVM application which, because of the way the client wants the data displayed, needs use template columns. They want some typical data-entry functionality though (pressing enter performs data checking, commits the row if valid, focuses on the first textbox of the next row; pressing tab focuses the next textbox...). Also, data is often imported from an external source into the grid, usually thousands of records at a time.

Right now, I have a Loaded event hooked up to each textbox which I am using to set focus after new rows are added. My problem is that the grid goes haywire when I import a lot of rows. As the user scrolls, the Loaded events are fired, and the grid becomes basically unusable. I disabled virtualization to prevent this, and find my grid taking up a gig of RAM in certain configurations, which is unacceptable. I can't figure out a way to get this grid to work the way they require without using a huge amount of memory. It seems as if I just need to be able to focus a textbox within a newly added row, 开发者_C百科but since the data validation is performed in the viewmodel, I don't have access to the new row in codebehind, so I can't just call "newtextbox.focus()" or whatever. I'm getting pretty desperate here, any suggestions would be massively appreciated.

Put an event listener in the code behind that can call your newtextbox.focus() (and whatever else you want to do). In the validation in the view model, fire the event with args that indicate what you want your grid to do.

Edit: OK, new approach. Try trapping the keystrokes, and on enter or tab do the things you want it to do.

This would be in your xaml

<Grid  KeyUp="myDataGrid_KeyUp" >

This would go in your code-behind

    private void myDataGrid_KeyUp(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Enter)
        {
            // do your enter stuff here, manipulate the view model for validation, etc.
        }
        else if (e.Key == Key.Tab)
        {
            // do your tab stuff here (get selected row, determine cell focus, focus on next cell)
        }
    }