added support to control DialogWindow propertes from style

Sandbox/Wpf/HelloWorld/HelloWorld/App.xaml.cs

@@ -21,7 +21,7 @@ protected override void RegisterTypes(IContainerRegistry containerRegistry)
             containerRegistry.RegisterDialog<ConfirmationDialog, ConfirmationDialogViewModel>();
 
             //register a custom window host
-            containerRegistry.RegisterDialogWindow<CustomDialogWindow>();
+            //containerRegistry.RegisterDialogWindow<CustomDialogWindow>();
         }
     }
 }

Sandbox/Wpf/HelloWorld/HelloWorld/Dialogs/ConfirmationDialog.xaml

@@ -4,6 +4,15 @@
              xmlns:prism="http://prismlibrary.com/"
              prism:ViewModelLocator.AutoWireViewModel="True"
              Width="300" Height="150">
+
+    <prism:DialogService.DialogWindowStyle>
+        <Style TargetType="Window">
+            <Setter Property="ResizeMode" Value="NoResize"/>
+            <Setter Property="ShowInTaskbar" Value="False"/>
+            <Setter Property="SizeToContent" Value="WidthAndHeight"/>
+        </Style>
+    </prism:DialogService.DialogWindowStyle>
+
     <Grid x:Name="LayoutRoot" Margin="5">
         <Grid.RowDefinitions>
             <RowDefinition />

Source/Wpf/Prism.Wpf/Ioc/IContainerRegistryExtensions.cs

@@ -5,6 +5,17 @@ namespace Prism.Ioc
 {
     public static class IContainerRegistryExtensions
     {
+        /// <summary>
+        /// Registers an object to be used as a dialog in the IDialogService.
+        /// </summary>
+        /// <typeparam name="TView">The Type of object to register as the dialog</typeparam>
+        /// <param name="containerRegistry"></param>
+        /// <param name="name">The unique name to register with the dialog.</param>
+        public static void RegisterDialog<TView>(this IContainerRegistry containerRegistry, string name = null)
+        {
+            containerRegistry.RegisterForNavigation<TView>(name);
+        }
+
         /// <summary>
         /// Registers an object to be used as a dialog in the IDialogService.
         /// </summary>

Source/Wpf/Prism.Wpf/Properties/AssemblyInfo.cs

@@ -23,5 +23,6 @@
 [assembly: XmlnsDefinition("http://prismlibrary.com/", "Prism.Mvvm")]
 [assembly: XmlnsDefinition("http://prismlibrary.com/", "Prism.Interactivity")]
 [assembly: XmlnsDefinition("http://prismlibrary.com/", "Prism.Interactivity.InteractionRequest")]
+[assembly: XmlnsDefinition("http://prismlibrary.com/", "Prism.Services.Dialogs")]
 
 

Source/Wpf/Prism.Wpf/Services/Dialogs/DefaultDialogs/DialogWindow.xaml

@@ -2,6 +2,11 @@
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         Title="{Binding Title}" Icon="{Binding IconSource}"
-        WindowStartupLocation="CenterOwner" SizeToContent="WidthAndHeight">
-
+        WindowStartupLocation="CenterOwner">
+    <Window.Style>
+        <Style TargetType="{x:Type Window}" >
+            <Setter Property="SizeToContent" Value="WidthAndHeight" />
+        </Style>
+    </Window.Style>
+
 </Window>

Source/Wpf/Prism.Wpf/Services/Dialogs/DialogService.cs

@@ -11,6 +11,19 @@ public class DialogService : IDialogService
     {
         private readonly IContainerExtension _containerExtension;
 
+        public static readonly DependencyProperty DialogWindowStyleProperty =
+            DependencyProperty.RegisterAttached("DialogWindowStyle", typeof(Style), typeof(DialogService), new PropertyMetadata(null));
+
+        public static Style GetDialogWindowStyle(DependencyObject obj)
+        {
+            return (Style)obj.GetValue(DialogWindowStyleProperty);
+        }
+
+        public static void SetDialogWindowStyle(DependencyObject obj, Style value)
+        {
+            obj.SetValue(DialogWindowStyleProperty, value);
+        }
+
         public DialogService(IContainerExtension containerExtension)
         {
             _containerExtension = containerExtension;
@@ -31,8 +44,6 @@ void ShowDialogInternal(string name, IDialogParameters parameters, Action<IDialo
             IDialogWindow dialogWindow = CreateDialogWindow();
             ConfigureDialogWindowEvents(dialogWindow, callback);
             ConfigureDialogWindowContent(name, dialogWindow, parameters);
-
-            dialogWindow.Owner = Application.Current.Windows.OfType<Window>().FirstOrDefault(x => x.IsActive);
 
             if (isModal)
                 dialogWindow.ShowDialog();
@@ -56,10 +67,9 @@ void ConfigureDialogWindowContent(string dialogName, IDialogWindow window, IDial
             if (viewModel == null)
                 throw new NullReferenceException("A dialog's ViewModel must implement the IDialogAware interface");
 
-            MvvmHelpers.ViewAndViewModelAction<IDialogAware>(viewModel, d => d.OnDialogOpened(parameters));
+            ConfigureDialogWindowProperties(window, dialogContent, viewModel);
 
-            window.Content = dialogContent;
-            window.DataContext = viewModel; //we want the host window and the dialog to share the same data contex
+            MvvmHelpers.ViewAndViewModelAction<IDialogAware>(viewModel, d => d.OnDialogOpened(parameters));            
         }
 
         void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, Action<IDialogResult> callback)
@@ -106,5 +116,20 @@ void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, Action<IDialogResul
                 };
             dialogWindow.Closed += closedHandler;
         }
+
+        void ConfigureDialogWindowProperties(IDialogWindow window, FrameworkElement dialogContent, IDialogAware viewModel)
+        {
+            var windowStyle = DialogService.GetDialogWindowStyle(dialogContent);
+            if (windowStyle != null)
+                window.Style = windowStyle;
+
+            window.Content = dialogContent;
+            window.DataContext = viewModel; //we want the host window and the dialog to share the same data contex
+
+            //TODO: is there a better way to set the owner
+            window.Owner = Application.Current.Windows.OfType<Window>().FirstOrDefault(x => x.IsActive);
+
+            //TODO: is the a good way to control the WindowStartupPosition (not a dependency property and can't be set in a style)
+        }
     }
 }

Source/Wpf/Prism.Wpf/Services/Dialogs/IDialogWindow.cs

@@ -25,5 +25,7 @@ public interface IDialogWindow
         event CancelEventHandler Closing;
 
         IDialogResult Result { get; set; }
+
+        Style Style { get; set; }
     }
 }