Usercontrol blendability wp7

Hi I'd like to make a simply user control

<UserControl x:Class="TestDependencyProps.controls.TestControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    DataContext="{Binding RelativeSource={RelativeSource Self}}"
    d:DesignHeight="480" d:DesignWidth="480">

    <Grid x:Name="LayoutRoot" >
        <TextBlock Height="30" Margin="31,140,27,0" Name="textBlock1" Text="{Binding testMessage}" VerticalAlignment="Top" />
    </Grid>

</UserControl>

Code behind:

public partial class TestControl : UserControl
{
    public string testMessage
    {
        get { return (string)GetValue(testMessageProperty); }
        set { SetValue(testMessageProperty, value); }
    }


    public static readonly DependencyProperty testMessageProperty =
        DependencyProperty.Register("testMessage", typeof(string), typeof(TestContro开发者_如何转开发l),new PropertyMetadata("test in a message",null)
        );

    public TestControl()
    {
        InitializeComponent();
    }
}

now all works but is not blendable ... and in Cider I can't see "test in a message"

there's a way that works :) without involve xmlns:MyControl=...

Most people consder that a control is Blendable if you can edit its template. To do this, you will have to change it from a user-control to a custom-control so that its template is defined in gerenic.xaml.

However, from your comments it sounds like you need design-time data, rather than to be able to make the control Blendable. Take a look at the MSDN section on design-time attributes in Silverlight. Specifically d:DataContext, this works just fine in WP7.

in addition to ColinE's answer, you might need to change a bit of your code to get your dependency property working with design time data,

    public string testMessage
    {
        get { return (string)GetValue(testMessageProperty); }
        set { SetValue(testMessageProperty, value); }
    }

public static readonly DependencyProperty testMessageProperty =
            DependencyProperty.Register("testMessage", typeof(string), typeof(TestControl), new PropertyMetadata("test in a message", PropertyChangedCallback));

        private static void PropertyChangedCallback(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            if (e.NewValue != null)
            {
                var c = (TestControl)sender;
                // assign value to the TextBlock here
                c.textBlock1.Text = e.NewValue.ToString();
            }
        }

and remove the binding in your TextBlock Text="{Binding testMessage}".

To display the text in design time, you need to add a design time DataContext (like what ColinE suggested),

<Grid x:Name="LayoutRoot" d:DataContext="{d:DesignInstance design:DesignMainViewModel, IsDesignTimeCreatable=True}">
    <xxx:TestControl testMessage={Binding SomeText} />
</Grid>

Hope this helps. :)

EDIT

Actually as Colin pointed out, you don't need the callback, if you name your usercontrol and use ElementName binding instead of the normal binding.

<UserControl x:Name="myUserControl" ...

Inside the TextBlock, you do

Text="{Binding testMessage, ElementName=myUserControl}"

Simply bind to testMessage wouldn't work because this property is of the UserControl.