C#•7mo ago

✅ WPF MouseOver expansion of item isn't working

I have a window with a bar that needs to hide down to a separator until the user mouses over it or checks a checkbox (which pins the bar to "open"). However, WPF seems to be claiming if the mouse is over the margin for the separator, it's not over the bar. The code is below.

                <Grid
                    x:Name="gridExtended"
                    DockPanel.Dock="Bottom"
                    IsMouseDirectlyOverChanged="OnExtendedToolBarMouseDirectlyOverChanged">
                    <Grid.RowDefinitions>
                        <RowDefinition
                            Height="10" />
                        <RowDefinition
                            Height="{Binding ExtendedToolBarRowTwoHeight, ElementName=window, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True}" />
                    </Grid.RowDefinitions>
                    <Separator
                        VerticalContentAlignment="Center"
                        HorizontalContentAlignment="Stretch"
                        Grid.ColumnSpan="25"
                        Height="1" />

                <Grid
                    x:Name="gridExtended"
                    DockPanel.Dock="Bottom"
                    IsMouseDirectlyOverChanged="OnExtendedToolBarMouseDirectlyOverChanged">
                    <Grid.RowDefinitions>
                        <RowDefinition
                            Height="10" />
                        <RowDefinition
                            Height="{Binding ExtendedToolBarRowTwoHeight, ElementName=window, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True}" />
                    </Grid.RowDefinitions>
                    <Separator
                        VerticalContentAlignment="Center"
                        HorizontalContentAlignment="Stretch"
                        Grid.ColumnSpan="25"
                        Height="1" />

        public System.Windows.GridLength ExtendedToolBarRowTwoHeight
        {
            get
            {
                if(gridExtended == null || chkExtendedToolBarShow == null)
                    System.Diagnostics.Debug.WriteLine("Nulls");
                else
                    System.Diagnostics.Debug.WriteLine($"Extended: {gridExtended.IsMouseDirectlyOver
                        }\tCheckbox: {chkExtendedToolBarShow.IsChecked}");
                return gridExtended != null && chkExtendedToolBarShow != null && (gridExtended.IsMouseDirectlyOver
                    || chkExtendedToolBarShow.IsChecked == true) ? System.Windows.GridLength.Auto : new
                    (0);
            }
        }

        public System.Windows.GridLength ExtendedToolBarRowTwoHeight
        {
            get
            {
                if(gridExtended == null || chkExtendedToolBarShow == null)
                    System.Diagnostics.Debug.WriteLine("Nulls");
                else
                    System.Diagnostics.Debug.WriteLine($"Extended: {gridExtended.IsMouseDirectlyOver
                        }\tCheckbox: {chkExtendedToolBarShow.IsChecked}");
                return gridExtended != null && chkExtendedToolBarShow != null && (gridExtended.IsMouseDirectlyOver
                    || chkExtendedToolBarShow.IsChecked == true) ? System.Windows.GridLength.Auto : new
                    (0);
            }
        }

What's going on? It should work so that the bar stays open if the mouse is anywhere over the bar, not just the separator.

8 Replies

JakenVeina•7mo ago

can I get a screenshot of the layout in question? I'm having trouble visualizing what you describe

Will Pittenger•7mo ago

Do these help?

JakenVeina•7mo ago

okay, so hovering over the separator should toggle the bar? try giving the Grid a background of Transparent

Will Pittenger•7mo ago

No, hovering over anywhere in its parent should reveal the rest of the bar. Only the separator is visible. The separator has a margin that should also cause the bar to expand.

JakenVeina•7mo ago

as opposed to a background of null

Will Pittenger•7mo ago

I did.

JakenVeina•7mo ago

uhhh well

Unlike IsMouseOver, this property is only true if the mouse pointer is over the literal element - as it is for a hit test. If the mouse pointer is instead over a child element, in particular over elements that are part of an element's deeper template and compositing, this property will be false.

Unlike IsMouseOver, this property is only true if the mouse pointer is over the literal element - as it is for a hit test. If the mouse pointer is instead over a child element, in particular over elements that are part of an element's deeper template and compositing, this property will be false.

use IsMouseOver

Will Pittenger•7mo ago

I found out about that after I started the thread. So it's not shown. Ah. That did it. Thank you.

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✅ WPF MouseOver expansion of item isn't working