CODEWITHSUNDEEP
c#wpftreeviewmouseenterrouted-events
Igor Soloydenko
Igor Soloydenko

Reputation: 11835

How to prevent WPF TreeView from raising MouseEnter on more than one Item?

I have the following pieces of code which should create a tree. Each item of that tree should change its background when it is hovered.

XAML:

<TreeView Name="treeView">
    <TreeViewItem Header="Item 1" IsExpanded="True">
        <TreeViewItem Header="Item 1.1" IsExpanded="True">
            <TreeViewItem Header="Item 1.1.1"/>
            <TreeViewItem Header="Item 1.1.1"/>
        </TreeViewItem>
        <TreeViewItem Header="Item 1.2"/>
    </TreeViewItem>
</TreeView>

C# Code behind:

class MainWindow : Window
{
    // ...

    private void SetEventHandlersOn(ItemCollection items)
    {
        foreach (TreeViewItem item in items)
        {
            item.MouseEnter += ItemMouseEnter;
            item.MouseLeave += ItemMouseLeave;
            SetEventHandlersOn(item.Items);
        }
    }

    private void ItemMouseEnter(object sender, MouseEventArgs e)
    {
        var treeViewItem = sender as TreeViewItem;
        treeViewItem.Background = Brushes.LimeGreen;
        e.Handled = true;
    }

    private void ItemMouseLeave(object sender, MouseEventArgs e)
    {
        var treeViewItem = sender as TreeViewItem;
        treeViewItem.Background = Brushes.White;
        e.Handled = true;
    }
}

Instead of doing what I need the tree appears differently. When I hover an item, it becomes highlighted, but its parent items are also highlighted for some reason.

enter image description here

How can I solve the problem?

UPD1 I see that my problem is very similar to the problem described here but I haven't understood yet how to apply the solution.

Upvotes: 1

Views: 1617

Answers (1)

Victorian
Victorian

Reputation: 41

you should check for e.Handled state in your handler like this:

private void ItemMouseEnter(object sender, MouseEventArgs e)
{
    if (!e.Handled)
    {
        var treeViewItem = sender as TreeViewItem;
        treeViewItem.Background = Brushes.LimeGreen;
        e.Handled = true;
    }
}

then it will be handled only once.

Upvotes: 4

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