Question

I have a UserControl where I’d like to have some parameters of customization “radius”(double) and “contentSource” (string[]).

My UserControl is composed of a few nested controls:

<UserControl ...>
<Grid>
    <my:Menu ...>
        <my:Button>
        </my:Button>
        <my:Button>
        </my:Button>
        <my:Button>
        </my:Button>
    </my:Menu ...>
</Grid>

I’m trying to expose the parameters with:

    public double Rad
    {
        get { return (double)GetValue(RadProperty); }
        set { SetValue(RadProperty, value); }
    }
    public static readonly DependencyProperty RadProperty =
        DependencyProperty.Register(
            "Radius",
            typeof(double),
            typeof(Menu));

    public String[] DataSource
    {
        get { return (String[])GetValue(DataSourceProperty); }
        set { SetValue(DataSourceProperty, value); }
    }
    public static readonly DependencyProperty DataSourceProperty =
        DependencyProperty.Register(
            "DataSource",
            typeof(String[]),
            typeof(Menu));

However, there seems to be two problems, the “string[]” parameter seems to be causing crashes, but mostly, I cannot set the “Radius” property at all. Is there something else I need to do to expose the parameter?

Answer 1

How are you trying to access the values? I have copied your code into a UserControl and it seems to work fine. Have you set the DataContext for the object you are accessing these values from?

Here is my test code, which might help:

 public partial class uc : UserControl
{
    public uc()
    {
        InitializeComponent();

        this.DataContext = this;
        this.DataSource = new string[] { "hello","There" };
        this.Rad = 7;
    }
    public String[] DataSource
    {
        get { return (String[])GetValue(DataSourceProperty); }
        set { SetValue(DataSourceProperty, value); }
    }
    public static readonly DependencyProperty DataSourceProperty =
        DependencyProperty.Register(
            "DataSource",
            typeof(String[]),
            typeof(uc));

    public double Rad
    {
        get { return (double)GetValue(RadProperty); }
        set { SetValue(RadProperty, value); }
    }
    public static readonly DependencyProperty RadProperty =
        DependencyProperty.Register(
            "Radius",
            typeof(double),
            typeof(uc));

}

and the XAML:

<UserControl x:Class="WpfApplication18.uc"
             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" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <StackPanel>
            <TextBox Text="{Binding Path=DataSource[0]}"></TextBox>
            <TextBox Text="{Binding Path=DataSource[1]}"></TextBox>
            <TextBox Text="{Binding Path=Radius}"></TextBox>
            <TextBox Text="{Binding Path=Radius}"></TextBox>
        </StackPanel>
    </Grid>
</UserControl>