Inherit DependencyProperties

Question

I have created several UserControls like a HeaderedDatePicker.

The XAML of this UserControl looks like:

<UserControl x:Class="Book.CustomControls.HeaderedDatePicker"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             DataContext="{Binding RelativeSource={RelativeSource Self}}"
             Width="200" Height="50">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" Margin="2,2" VerticalAlignment="Center" Text="{Binding Header}" FontWeight="{Binding HeaderFontWeight}"/>
        <DatePicker Grid.Row="1" Margin="2,2" VerticalAlignment="Center" SelectedDate="{Binding Date, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
    </Grid>
</UserControl>

The Code-Behind with the registered DependencyPropertys is:

public partial class HeaderedDatePicker : UserControl
{
    public HeaderedDatePicker()
    {
        this.InitializeComponent();
        this.HeaderFontWeight = FontWeights.Normal;
        this.Date = DateTime.Now;
    }

    public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register("Header", typeof(string), typeof(HeaderedDatePicker));
    public static readonly DependencyProperty HeaderFontWeightProperty = DependencyProperty.Register("HeaderFontWeight", typeof(FontWeight), typeof(HeaderedDatePicker));
    public static readonly DependencyProperty DateProperty = DependencyProperty.Register("Date", typeof(DateTime), typeof(HeaderedDatePicker));

    public string Header
    {
        get { return (string)GetValue(HeaderProperty); }
        set { SetValue(HeaderProperty, value); }
    }

    public FontWeight HeaderFontWeight
    {
        get { return (FontWeight)GetValue(HeaderFontWeightProperty); }
        set { SetValue(HeaderFontWeightProperty, value); }
    }

    public DateTime Date
    {
        get { return (DateTime)GetValue(DateProperty); }
        set { SetValue(DateProperty, value); }
    }
}

Everything is working fine. Now I want to create another HeaderedControl like a HeaderedComboBox or so. My question now is:

Do I have to write the HeaderProperty and HeaderFontWeightProperty in each Code-Behind-File or is there a way to do this in a base-class?

I tried to create a base-class where the properties are registered, but in the code-behind of the HeaderedDatePicker I couldn't inherit from my class

Answer 1

public class main : UserControl
{
    public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register("Header", typeof(string), typeof(main));
    public static readonly DependencyProperty HeaderFontWeightProperty = DependencyProperty.Register("HeaderFontWeight", typeof(FontWeight), typeof(main));
    public static readonly DependencyProperty DateProperty = DependencyProperty.Register("Date", typeof(DateTime), typeof(main));

    public string Header
    {
        get { return (string)GetValue(HeaderProperty); }
        set { SetValue(HeaderProperty, value); }
    }

    public FontWeight HeaderFontWeight
    {
        get { return (FontWeight)GetValue(HeaderFontWeightProperty); }
        set { SetValue(HeaderFontWeightProperty, value); }
    }

    public DateTime Date
    {
        get { return (DateTime)GetValue(DateProperty); }
        set { SetValue(DateProperty, value); }
    }

}

Then in every UserControl you are supposed to derive from previously declared main.

    public partial class HeaderedComboBox : main
{
    public HeaderedComboBox()
    {
        this.InitializeComponent();
        this.DataContext = this;
    } 
}

Finally

<local:main x:Class="WpfApplication5.HeaderedComboBox"
         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" 
         xmlns:local ="clr-namespace:WpfApplication5"
         mc:Ignorable="d" 
         Width="200" Height="50">
<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition/>
    </Grid.RowDefinitions>
    <TextBlock Grid.Row="0" Margin="2,2" VerticalAlignment="Center" Text="{Binding Header}" FontWeight="{Binding HeaderFontWeight}"/>
    <ComboBox Grid.Row="1" Margin="2,2" VerticalAlignment="Center" ItemsSource="{Binding ItemsSource, UpdateSourceTrigger=PropertyChanged}"
              SelectedItem="{Binding SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Grid>

Let me know whether it works.

Answer 2

You can register attached property. See this link. Attached property can be used for any dependency object.