Fix crash when step property is missing on Windows. (#259)

Co-authored-by: Igor Klemenski <[email protected]>

Author: rectified95

src/windows/SliderWindows/SliderView.cpp

@@ -80,7 +80,7 @@ namespace winrt::SliderWindows::implementation {
                 }
                 else {
                     updatedMaxValue = true;
-                    m_maxValue = propertyValue.AsInt64();
+                    m_maxValue = propertyValue.AsDouble();
                 }
             }
             else if (propertyName == "minimumValue") {
@@ -89,16 +89,19 @@ namespace winrt::SliderWindows::implementation {
                 }
                 else {
                     updatedMinValue = true;
-                    m_minValue = propertyValue.AsInt64();
+                    m_minValue = propertyValue.AsDouble();
                 }
             }
             else if (propertyName == "step") {
                 if (propertyValue.IsNull()) {
                     this->ClearValue(xaml::Controls::Slider::StepFrequencyProperty());
                 }
-                else {
+                else if (propertyValue.AsDouble() != 0) {
                     this->StepFrequency(propertyValue.AsDouble());
                 }
+                else {
+                    this->StepFrequency(c_stepDefault);
+                }
             }
             else if (propertyName == "inverted") {
                 if (propertyValue.IsNull()) {

src/windows/SliderWindows/SliderView.h

@@ -35,8 +35,8 @@ namespace winrt::SliderWindows::implementation {
             winrt::Windows::Foundation::IInspectable const& sender,
             xaml::Input::ManipulationCompletedRoutedEventArgs const& args);
 
-        int64_t m_maxValue, m_minValue;
-        double m_value;
+        double m_value, m_maxValue, m_minValue;
+        const double c_stepDefault = 0.1;
     };
 }