Add CornerRadius dependency to SnackBar and TemplateBinding

Author: HedpE-

src/MaterialDesignThemes.Wpf/Snackbar.cs

@@ -1,4 +1,5 @@
-using System.Windows.Media.Animation;
+using System.ComponentModel;
+using System.Windows.Media.Animation;
 using System.Windows.Threading;
 
 namespace MaterialDesignThemes.Wpf;
@@ -186,4 +187,15 @@ public SnackbarActionButtonPlacementMode ActionButtonPlacement
         get => (SnackbarActionButtonPlacementMode)GetValue(ActionButtonPlacementProperty);
         set => SetValue(ActionButtonPlacementProperty, value);
     }
+
+    public static readonly DependencyProperty CornerRadiusProperty = DependencyProperty.Register(
+        nameof(CornerRadius), typeof(Thickness), typeof(Snackbar), new PropertyMetadata(new Thickness(0)));
+
+    [Bindable(true)]
+    [Category("Appearance")]
+    public Thickness CornerRadius
+    {
+        get => (Thickness)GetValue(CornerRadiusProperty);
+        set => SetValue(CornerRadiusProperty, value);
+    }
 }

src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.Snackbar.xaml

@@ -130,6 +130,7 @@
     <Setter Property="ActionButtonStyle" Value="{StaticResource MaterialDesignSnackbarActionButton}" />
     <Setter Property="Background" Value="{DynamicResource MaterialDesign.Brush.SnackBar.Background}" />
     <Setter Property="ClipToBounds" Value="True" />
+    <Setter Property="CornerRadius" Value="3" />
     <Setter Property="FontSize" Value="14" />
     <Setter Property="Foreground" Value="{DynamicResource MaterialDesign.Brush.Background}" />
     <Setter Property="HorizontalAlignment" Value="Center" />
@@ -191,9 +192,9 @@
                     MinHeight="48"
                     VerticalAlignment="Stretch"
                     Background="{TemplateBinding Background}"
-                    CornerRadius="3"
                     BorderBrush="{TemplateBinding BorderBrush}"
                     BorderThickness="{TemplateBinding BorderThickness}"
+                    CornerRadius="{TemplateBinding CornerRadius}"
                     SnapsToDevicePixels="True">
               <ContentPresenter x:Name="ContentPresenter"
                                 Margin="{TemplateBinding Padding}"