WPF & Listview. Shift - selecting multiple items. Wrong start item

问题

Problem explained:

Given a list containing 10 items.

My first action is to (mouse) click on the second item.
Secondly I have a button which is supposed to programmatically select an item.

For example:

listView.SelectedIndex = 4; 
//or
listView.SelectedItems.Add(listView.Items[4]);

The item is correctly selected.

If I now press SHIFT and select the LAST item the selection starts at the clicked item and not the programmatically selected item.

One solution was to simulate a mouse click event, which worked but had side effects. Its also way to hacky.

It seems that the mouse event stores the starting item.

Is there something I have overlooked?

回答1:

I've asked on MSDN about this issue. Surprisingly the cause of this problem is SelectionMode

The problem may be in the ListBox code (ListView derives from ListBox):

protected override void OnSelectionChanged(SelectionChangedEventArgs e)
{   ...
    if ((this.SelectionMode == SelectionMode.Single) && (base.SelectedItem != null))
    {
       ...
        if (selectedItem != null)
        {
            this.UpdateAnchorAndActionItem(selectedItem);
    }
}

The UpdateAnchorAndActionItem(selectedItem) is not called if the SelectionMode is Extended.

So, in the code behind you have to do next:

list.SelectionMode = SelectionMode.Single;
list.SelectedIndex = 4;
list.SelectionMode = SelectionMode.Extended;

Don't quite understand how be in case of MVVM.

Upd1

I have created custom ListView. It will do inside the mentioned above logic. In this case it must work as you expect even in MVVM. I hope it will help you.

public class MyListView:ListView
{
    protected override void OnSelectionChanged(SelectionChangedEventArgs e)
    {
        //if it is multiselection than execute standard logic
        if(SelectedItems.Count!=1)
        {
            base.OnSelectionChanged(e);
            return;
        }
        var mode = SelectionMode;
        SelectionMode = SelectionMode.Single;
        base.OnSelectionChanged(e);
        SelectionMode=mode;
    }
}

来源：https://stackoverflow.com/questions/11950021/wpf-listview-shift-selecting-multiple-items-wrong-start-item

标签

wpf

listview

multipleselection