Merge pull request #1153 from nishy2000/issue-1152-ObjectToImageConverter-null-exception

Issue 1152 ObjectToImageConverter null exception

Author: batzen

Fluent.Ribbon.Showcase/TestContent.xaml

@@ -3588,6 +3588,9 @@
                         </GroupBox>
                         <GroupBox Header="Issue repros">
                             <WrapPanel>
+                                <WrapPanel.Resources>
+                                    <Fluent:ObjectToImageConverter x:Key="StringToImageConvert"/>
+                                </WrapPanel.Resources>
                                 <Fluent:Button x:Name="SleepButton"
                                                VerticalAlignment="Top"
                                                Click="SleepButton_OnClick"
@@ -3602,6 +3605,13 @@
                                     Change theme from thread
                                 </Fluent:Button>
 
+                                <Fluent:Button VerticalAlignment="Top"
+                                               Tag="/Images/Blue.png"
+                                               Icon="{Binding Path=Tag,RelativeSource={RelativeSource Self},Converter={StaticResource StringToImageConvert}}"
+                                               Size="Middle">
+                                    ObjectToImageConverter for issue #1152
+                                </Fluent:Button>
+
                                 <GroupBox Header="KeyTip issues #254">
                                     <StackPanel Orientation="Vertical">
                                         <formsInterop:WindowsFormsHost>

Fluent.Ribbon.Tests/Converters/ObjectToImageConverterTests.cs

@@ -41,4 +41,35 @@ public void TestDynamicResource()
         Assert.That(drawingGroup.Children.Cast<GeometryDrawing>().Select(x => x.Geometry.ToString()),
             Is.EquivalentTo(((DrawingGroup)((DrawingImage)Application.Current.FindResource(fluentRibbonImagesApplicationmenuResourceKey)).Drawing).Children.Cast<GeometryDrawing>().Select(x => x.Geometry.ToString())));
     }
-}
+
+    private class DummyProvider : IServiceProvider
+    {
+        object IServiceProvider.GetService(Type serviceType)
+        {
+            return null;
+        }
+    }
+
+    [Test]
+    public void TestStaticResourceSequnece()
+    {
+        var fluentRibbonImagesApplicationmenuResourceKey = (object)"Fluent.Ribbon.Images.ApplicationMenu";
+
+        var expressionType = typeof(ResourceReferenceExpressionConverter).Assembly.GetType("System.Windows.ResourceReferenceExpression");
+
+        var expression = Activator.CreateInstance(expressionType, fluentRibbonImagesApplicationmenuResourceKey);
+
+        var converter = new ObjectToImageConverter();
+
+        converter.ProvideValue(new DummyProvider());
+
+        var convertedValue = StaticConverters.ObjectToImageConverter.Convert(new object[]
+        {
+            expression, // value to convert
+            new ApplicationMenu() // target visual
+        }, null, null, null);
+
+        Assert.That(convertedValue, Is.Not.Null);
+        Assert.That(convertedValue, Is.InstanceOf<Image>());
+    }
+}

Fluent.Ribbon/Converters/ObjectToImageConverter.cs

@@ -224,6 +224,11 @@ public override object ProvideValue(IServiceProvider serviceProvider)
 
     private object CreateMultiBinding(IServiceProvider serviceProvider)
     {
+        if (this.IconBinding is null)
+        {
+            return this;
+        }
+
         var multiBinding = new MultiBinding
         {
             Converter = this