Fixing exception that can occur if there are no visual children when trying to find the appropriate name scope. (#1160)

Keboo · web-flow · commit fb0fc463ab4c · 2019-01-07T10:17:51.000-08:00
Fixes #1159
diff --git a/MaterialDesignThemes.Wpf/Transitions/TransitioningContentBase.cs b/MaterialDesignThemes.Wpf/Transitions/TransitioningContentBase.cs
@@ -131,7 +131,7 @@ private FrameworkElement GetNameScopeRoot()
         {
             //https://github.com/ButchersBoy/MaterialDesignInXamlToolkit/issues/950
             //Only set the NameScope if the child does not already have a TemplateNameScope set
-            if (GetVisualChild(0) is FrameworkElement fe && NameScope.GetNameScope(fe) != null)
+            if (VisualChildrenCount > 0 && GetVisualChild(0) is FrameworkElement fe && NameScope.GetNameScope(fe) != null)
             {
                 return fe;
             }

Original file line number	Diff line number	Diff line change
`@@ -131,7 +131,7 @@ private FrameworkElement GetNameScopeRoot()`
`131`	`131`	`{`
`132`	`132`	`//https://github.com/ButchersBoy/MaterialDesignInXamlToolkit/issues/950`
`133`	`133`	`//Only set the NameScope if the child does not already have a TemplateNameScope set`
`134`		`- if (GetVisualChild(0) is FrameworkElement fe && NameScope.GetNameScope(fe) != null)`
	`134`	`+ if (VisualChildrenCount > 0 && GetVisualChild(0) is FrameworkElement fe && NameScope.GetNameScope(fe) != null)`
`135`	`135`	`{`
`136`	`136`	`return fe;`
`137`	`137`	`}`