Wednesday, December 12, 2007

WPF ListView - Getting the Clicked Item

I recently had the need to figure out which item in a WPF ListView was under the mouse when it was clicked. The solution wasn't completely straightforward, so I thought I'd post it here.

First, obviously you need to register a mouse button event hander in your control initialization. In this case, I'm using a double-click event:
MyListView.MouseDoubleClick += new MouseButtonEventHandler(MyListView_MouseDoubleClick);
and then implement the event handler like such:
void MyListView_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
DependencyObject dep = (DependencyObject)e.OriginalSource;

while ((dep != null) && !(dep is ListViewItem))
{
dep = VisualTreeHelper.GetParent(dep);
}

if (dep == null)
return;

MyDataItemType item = (MyDataItemType)MyListView.ItemContainerGenerator.ItemFromContainer(dep);

// Do something with the item...
}
What we are doing is walking up the visual tree starting at the element the generated the mouse event. We stop when we find a ListViewItem, which we can then use to get the corresponding data item. If all you want is the index of the item, use IndexFromContainer() instead.

23 comments:

  1. I saw how to get row or item, but how can I get column information from the mouse click position?

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  2. Try this and see how it works...
    System.Data.DataRowView value = (System.Data.DataRowView)ListViewEmployeeDetails.SelectedValue;
    MessageBox.Show(value.Row[0].ToString());

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    Replies
    1. Thanks man its works for me..........:)

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  3. Thanks much, you just saved me some time figuring it out. Here is a VB version.
    Dim clickedToDoItem As ToDoItemInfo
    Dim dep As DependencyObject = CType(e.OriginalSource, DependencyObject)
    Do While dep IsNot Nothing AndAlso Not TypeOf (dep) Is ListViewItem
    dep = VisualTreeHelper.GetParent(dep)
    Loop
    If dep Is Nothing Then
    Return
    Else
    clickedToDoItem = CType(Me.lvToDo.ItemContainerGenerator.ItemFromContainer(dep), ToDoItemInfo)
    End If
    MessageBox.Show(String.Format("You clicked item: date={0},description={1}", clickedToDoItem.Due, clickedToDoItem.Description))

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  4. Thanks for the info. It worked great in my project and helped me solve two issues I was having. I really am starting to like WPF, but it is still taking a long time to figure it all out.

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  5. This code fails if the OriginalSource is derived from FrameworkContentElemnt (e.g. anything in a FlowDocument, such as Document.Run). Unfortunately, VisualTreeHelper deals with Visual and FrameworkElement objects, but not FrameworkContentElement objects. 8-|

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  6. As the last comment indicated, you need to handle ContentElement's differently. If you hit a content element then you should get the logical parent.

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  7. Thanks a lot for this. Was searching around for ages and found yours to be the most concise method. Thanks

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  8. hi
    great code tnx!

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  9. Using

    MyDataItemType item = (MyDataItemType)((ListViewItem)dep).DataContext

    instead of

    MyDataItemType item = (MyDataItemType)MyListView.ItemContainerGenerator.ItemFromContainer(dep);

    is a bit more straight forward but may only work, if data source binding is used for the list view.

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  10. That's overly complex.

    Why would you do that?

    If you have a listview, just do

    <ListView SelectedItem="TheSelectedItem" ... >

    and in the setter for TheSelectedItem do what you want with it.

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  11. I'm assuming you mean to use a binding to TheSelectedItem, but anyway that wouldn't work in my particular case for at least two reasons:

    1. I'm using a multi-selected ListView (SelectionMode of Multiple), so SelectedItem is meaningless.

    2. I only want to act in response to mouse double-clicks, not selection.

    Responding to a selection is easy, but it isn't what I'm trying to do. In any case, if you want take action on a selection change, a better way to do that is to use the SelectionChanged event.

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  12. You can use this as well:

    http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/681dea50-6bd2-4676-8161-14416386778d

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  13. Or..


    private void appList_MouseDoubleClick(object sender, RoutedEventArgs e) {
    ListViewItem app = (ListViewItem)appList.Items[appList.SelectedIndex];
    MessageBox.Show("you selected: " + app.Content);
    }

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  14. Very Good post!

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  15. I'm not sure if it would work in your case, Mike, but this worked for me:
    private void ListViewItem_MouseDoubleClick(object sender, MouseButtonEventArgs e)
    {
    ListViewItem listViewItemSender = sender as ListViewItem;
    MyBusinessObject doubleClickedBO = myListView.ItemContainerGenerator.ItemFromContainer(listViewItemSender) as MyBusinessObject;
    }

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  16. Nice dude! That worked perfectly. :)
    I am trying to learn WPF and I had been struggling with this for days!
    Thanks!

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  17. No one is having a problem with the error "expression of type 'System.Windows.DependencyObject' can never be of type 'System.Windows.Forms.ListViewItem'"??? I'm not sure what I'm doing wrong here...

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  18. Thank you for this post!

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  19. This is really useful. Thanks for the tip about getting the index number from IndexFromContainer().

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