Question

Here is my user control(MonthCal)’s code behind.

public partial class MonthCal : UserControl
{
    public DayOfWeek StartDayOfWeek { get { return (DayOfWeek)GetValue(StartDayOfWeekProperty); } set { SetValue(StartDayOfWeekProperty, value); } }
    public static readonly DependencyProperty StartDayOfWeekProperty = DependencyProperty.Register("StartDayOfWeek", typeof(DayOfWeek), typeof(MonthCellHeader), new UIPropertyMetadata(DayOfWeek.Sunday, StartDayOfWeek_PropertyChanged));
    //...
}

and also, here is a xaml of the MonthCal.

<UserControl x:Class="GCDR.MonthCal"
             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">
    <!-- ... -->
</UserControl>

And so, How can I set the ‘StartDayOfWeek’ dependency property in xaml? as you guys know, the following code is impossible:

<UserControl ...
             StartDayOfWeek="Sunday">
</UserControl>

Please give me a help.

Answer 1

You can not use the dependency property in markup of the UserControl but you can use it when you place instance of the user control somewhere like so:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication1">
    <Grid>
        <local:UserControl1 local:StartDayOfWeek="Friday" />
    </Grid>
</Window>

With in your user control you can bind some other property to your dependency property like so:

<UserControl x:Class="WpfApplication1.UserControl1"
             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:WpfApplication1"
             mc:Ignorable="d" >
    <Grid>
        <Label Content="{Binding RelativeSource={RelativeSource AncestorType=local:UserControl1},Path=StartDayOfWeek}"  />
    </Grid>
</UserControl>