Style not working with a custom ListView

Question

I have a assembly where I define several customs controls (based on existing control) with their own style.

For all of them I define the static constructor where I set DefaultStyleKeyProperty and add the style XAML file to Themes/Generic.xaml.

It's working fine for all of them except for my custom ListView.. It's driving me crazy !

Here is a short sample :

public class EmListView : ListView
{
    /// <summary>
    /// Constructor
    /// </summary>
    static EmListView()
    {
        // Set the default style type
        DefaultStyleKeyProperty.OverrideMetadata(typeof(EmListView), new FrameworkPropertyMetadata(typeof(EmListView)));
    }
}

XAML file declared in Generic.xaml :

<Style TargetType="{x:Type ui:EmListView}">
    <Setter Property="SnapsToDevicePixels" Value="true"/>
    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
    <Setter Property="ScrollViewer.CanContentScroll" Value="True"/>
    <Setter Property="VerticalContentAlignment" Value="Stretch"/>
    <Setter Property="HorizontalContentAlignment" Value="Stretch" />

    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ui:EmListView}">

                <Border Name="Border" Style="{DynamicResource EMLV_ListViewBorderStyle}" Margin="50">
                    <ScrollViewer Style="{DynamicResource {x:Static GridView.GridViewScrollViewerStyleKey}}">
                        <ItemsPresenter />
                    </ScrollViewer>
                </Border>

                <ControlTemplate.Triggers>
                    <Trigger Property="IsGrouping" Value="true">
                        <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                    </Trigger>

                    <Trigger Property="IsEnabled" Value="False">
                        <Setter Property="Opacity" Value="0.3" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

I don't know why but the only way to get my style applied on my EmListView is to force the style when using it, like :

<ui:EmListView Margin="5" Style="{DynamicResource {x:Type ui:EmListView}}">

I have EmWindow, EmButton, .. All are applying the style automatically except that ListView. Is there something special with ListView ?

Thank you.

EDIT :

I spotted something, it seem that is the declaration of my EmListView that cause the trouble.

Here is a sample declaration inside a window :

                <ui:EmListView Margin="5">
                <ui:EmListView.View>
                    <GridView>

                        <ui:EmSortableGridViewColumn Width="100" DisplayMemberBinding="{Binding artCode, Mode=OneWay}" SortPropertyName="artCode" Header="Code" IsDefaultSortColumn="True" />

                        <ui:EmSortableGridViewColumn Width="100" DisplayMemberBinding="{Binding artCode, Mode=OneWay}" SortPropertyName="artCode" Header="Code" IsDefaultSortColumn="True" />

                        <ui:EmSortableGridViewColumn Width="100" DisplayMemberBinding="{Binding artCode, Mode=OneWay}" SortPropertyName="artCode" Header="Code" IsDefaultSortColumn="True" />

                        <ui:EmSortableGridViewColumn Width="100" DisplayMemberBinding="{Binding artCode, Mode=OneWay}" SortPropertyName="artCode" Header="Code" IsDefaultSortColumn="True" />

                    </GridView>
                </ui:EmListView.View>
            </ui:EmListView>

The style doesn't apply and it constantly throw me a warning saying that it cannot define OverridesDefaultStyle property in the style.

If I simply declare it like this :

<ui:EmListView Margin="5" />

I have no warning and my style is set correctly.

Answer 1

I solved my issue, I did a crappy workaround in my EmListView constructor as follow :

    public EmListView()
    {
        Style defaultStyle = (Style)Application.Current.TryFindResource(typeof(EmListView));
        if (defaultStyle != null)
        {
            this.OverridesDefaultStyle = true;
            this.Style = defaultStyle;
        }
    }

If someone can tell me why I have to do this trick only for my custom ListView control I will be happy to know.