Create a WPF Custom ComboBox

Question

What I'm trying to do is a combobox that have the favorite values on top, with a different background color and button. Right now I have:

<UserControl x:Class="ComboBoxWithButton"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d"
             Name="root"
             d:DesignWidth="300" Height="25">

    <ComboBox 
         x:Name="ComboBoxBtn" 
         VerticalAlignment="Top" 
         HorizontalAlignment="Left" 
         Margin="0,0,0,-1" 
         Width="300" 
         ItemsSource="{Binding Source, RelativeSource={RelativeSource AncestorType=UserControl}}"
         SelectedItem="{Binding Path=Selected, Mode=TwoWay, RelativeSource={RelativeSource AncestorType=UserControl}}">
       <ComboBox.Resources>
            <Style TargetType="ComboBoxItem">
                ????
            </Style>
        </ComboBox.Resources>
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.Style>
                        <Style TargetType="Grid">
                            <Setter Property="Background" Value="#FFE6E6FA"/>
                        </Style>
                    </Grid.Style>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Label Content="{Binding}" Width="250" />
                    <Button Grid.Column="1" Command="{Binding CommandButton, ElementName=root}"
                            CommandParameter="{Binding}">+</Button>
                </Grid>
            </DataTemplate>

        </ComboBox.ItemTemplate>
    </ComboBox>
</UserControl>

Right now I have an Add button so I can add my items as favorites. But what I want now is, based on the item I represent it as favorite or not.

Case is a favorite have a different background color an a [-] button (to remove). Case is not the background is white as usual and have a [+].

If you want to add buttons you will need to modify the ComboBox control template, which is here, msdn.microsoft.com/en-us/library/dd334408%28v=vs.95%29.aspx — patrick
– patrick, Commented Oct 4, 2016 at 14:46
My main problem is not the button. Is how I can "say" if the item is a favorite (with the help of a method that checks if he favorite or not) then do this, otherwise do that. — Andre Roque
– Andre Roque, Commented Oct 4, 2016 at 14:47
You could have a Grid with the two controls. One control has a binding Visibility = IsFavorite and the other Visibility = IsNotFavorite — patrick
– patrick, Commented Oct 4, 2016 at 14:51
You need another ItemsControl which have your "Favorites" as an ItemsSource. This is as @ÞÄTRÏÇK mentioned in the ComboBox control template not in the ItemTemplate — Mat
– Mat, Commented Oct 4, 2016 at 14:52
And I do that in the same XAML file? But with 2 different ControlTemplate? Can you just give me a small example please? — Andre Roque
– Andre Roque, Commented Oct 4, 2016 at 14:54

AnjumSKhan · Accepted Answer · 2016-10-04 15:59:30Z

1

See if a ContentControl helps you here in place of where you are using a Button.

 <ComboBox.ItemTemplate>
 <DataTemplate>
 <ContentControl>
    <Style TargetType="ContentControl">
        <Style.Triggers>
            <DataTrigger Binding="{Binding ...}" Value="True">
                <Setter Property="Content">
                    <Setter.Value>
                            <Grid>
                                <Grid.Style>
                                    <Style TargetType="Grid">
                                        <Setter Property="Background" Value="#FFE6E6FA"/>
                                    </Style>
                                </Grid.Style>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto" />
                                    <ColumnDefinition Width="Auto" />
                                </Grid.ColumnDefinitions>
                                <Label Content="{Binding}" Width="250" />
                                <Button Grid.Column="1" Command="{Binding CommandButton, ElementName=root}"
                        CommandParameter="{Binding}">+</Button>
                            </Grid>
                        </Setter.Value>
                </Setter>
            </DataTrigger>
            <DataTrigger Binding="{Binding ...}" Value="False">
                <Setter Property="Content">
                    <Setter.Value>
                            <Grid>
                                <Grid.Style>
                                    <Style TargetType="Grid">
                                        <Setter Property="Background" Value="Yellow"/>
                                    </Style>
                                </Grid.Style>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto" />
                                    <ColumnDefinition Width="Auto" />
                                </Grid.ColumnDefinitions>
                                <Label Content="{Binding}" Width="250" />
                                <Button Grid.Column="1" Command="{Binding CommandButton, ElementName=root}"
                                    CommandParameter="{Binding}">-</Button>
                            </Grid>
                        </Setter.Value>
                </Setter>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</ContentControl>
</DataTemplate>
</ComboBox.ItemTemplate>

edited Oct 4, 2016 at 15:59

answered Oct 4, 2016 at 15:53

AnjumSKhan

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5 Comments

Andre Roque Over a year ago

I guess it help regarding the button part and about the Background? What shoud I put on the bidding?

AnjumSKhan Over a year ago

@AndreRoque u can use ContentControl as DataTemplate itself and change Button part urself.

Andre Roque Over a year ago

Thanks a lot! And if I understand correctly then I bind the 2 different DataContext right?

AnjumSKhan Over a year ago

@AndreRoque 2 diff DC ? where buttons ?

AnjumSKhan Over a year ago

No one can stop you from binding whatever u like.

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