WPF UserControl Design Time Size

Question

When creating a UserControl in WPF, I find it convenient to give it some arbitrary Height and Width values so that I can view my changes in the Visual Studio designer. When I run the control, however, I want the Height and Width to be undefined, so that the control will expand to fill whatever container I place it in. How can I acheive this same functionality without having to remove the Height and Width values before building my control? (Or without using DockPanel in the parent container.)

The following code demonstrates the problem:

<Window x:Class="ExampleApplication3.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:loc="clr-namespace:ExampleApplication3"
    Title="Example" Height="600" Width="600">
    <Grid Background="LightGray">
        <loc:UserControl1 />
    </Grid>
</Window>

The following definition of UserControl1 displays reasonably at design time but displays as a fixed size at run time:

<UserControl x:Class="ExampleApplication3.UserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="300" Width="300">
    <Grid Background="LightCyan" />
</UserControl>

The following definition of UserControl1 displays as a dot at design time but expands to fill the parent Window1 at run time:

<UserControl x:Class="ExampleApplication3.UserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Grid Background="LightCyan" />
</UserControl>

Answer 1

Here are a list of Design-Time Attributes in the Silverlight Designer. They are the same for the WPF designer.

It lists all of the d: values available in the Designer such as d:DesignHeight, d:DesignWidth, d:IsDesignTimeCreatable, d:CreateList and several others.

Answer 2

I was looking for similar solution like the one used in Blend and with your mentions I created simple behavior class with two attached properties Width & Height that are applied only in DesinTime

public static class DesignBehavior 
{
    private static readonly Type OwnerType = typeof (DesignBehavior);

    #region Width

    public static readonly DependencyProperty WidthProperty =
        DependencyProperty.RegisterAttached(
            "Width",
            typeof (double),
            OwnerType,
            new FrameworkPropertyMetadata(double.NaN, new PropertyChangedCallback(WidthChangedCallback)));

    public static double GetWidth(DependencyObject depObj)
    {
        return (double)depObj.GetValue(WidthProperty);
    }

    public static void SetWidth(DependencyObject depObj, double value)
    {
        depObj.SetValue(WidthProperty, value);
    }

    private static void WidthChangedCallback(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
    {
        if (DesignerProperties.GetIsInDesignMode(depObj)) {
            depObj.SetValue(FrameworkElement.WidthProperty, e.NewValue);
        }
    }

    #endregion

    #region Height

    public static readonly DependencyProperty HeightProperty =
        DependencyProperty.RegisterAttached(
            "Height",
            typeof (double),
            OwnerType,
            new FrameworkPropertyMetadata(double.NaN, new PropertyChangedCallback(HeightChangedCallback)));

    public static double GetHeight(DependencyObject depObj)
    {
        return (double)depObj.GetValue(HeightProperty);
    }

    public static void SetHeight(DependencyObject depObj, double value)
    {
        depObj.SetValue(HeightProperty, value);
    }


    private static void HeightChangedCallback(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
    {
        if (DesignerProperties.GetIsInDesignMode(depObj)) {
            depObj.SetValue(FrameworkElement.HeightProperty, e.NewValue);
        }
    }

    #endregion

}

Then in your UserControl you just set these properties in Xaml

<UserControl x:Class="ExtendedDataGrid.Views.PersonOverviewView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:tool="http://schemas.microsoft.com/wpf/2008/toolkit"
    xmlns:b="clr-namespace:ExtendedDataGrid.Behaviors"
    b:DesignBehavior.Width="600" b:DesignBehavior.Height="200">
    <Grid>
         ...
    </Grid>
</UserControl>

Answer 3

In Visual Studio add the Width and Height attribute to your UserControl XAML, but in the code-behind insert this

public UserControl1()
{
    InitializeComponent();
    if (LicenseManager.UsageMode != LicenseUsageMode.Designtime)
    {
        this.Width = double.NaN; ;
        this.Height = double.NaN; ;
    }
}

This checks to see if the control is running in Design-mode. If not (i.e. runtime) it will set the Width and Height to NaN (Not a number) which is the value you set it to if you remove the Width and Height attributes in XAML.

So at design-time you will have the preset width and height (including if you put the user control in a form) and at runtime it will dock depending on its parent container.

Hope that helps.

Answer 4

For Blend, a little known trick is to add these attributes to your usercontrol or window:

 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
mc:Ignorable="d"
       d:DesignHeight="500" d:DesignWidth="600"

This will set the design height and width to 500 and 600 respectively. However this will only work for the blend designer. Not the Visual Studio Designer.

As far as the Visual Studio Designer your technique is all that works. Which is why I don't use the Visual Studio Designer. ;)

Answer 5

Thanks to the original answerer for this solution! For those that are interested, here it is in VB:

If LicenseManager.UsageMode <> LicenseUsageMode.Designtime Then
    Me.Width = Double.NaN
    Me.Height = Double.NaN
End If

Answer 6

I do this all the time. Simply set the width and height values to "auto" where you instantiate your control, and this will override the design-time values for that UserControl.

ie: <loc:UserControl1 Width="auto" Height="auto" />

Another option is to set a combination of MinWidth and MinHeight to a size that allows design-time work, while Width and Height remain "auto". Obviously, this only works if you don't need the UserControl to size smaller than the min values at runtime.