unioned FileTypeChoices

Author: DinahK-2SO

dev/Interop/StoragePickers/PickerCommon.cpp

@@ -349,7 +349,7 @@ namespace PickerCommon {
         FileTypeFilterData.clear();
         FileTypeFilterData.reserve(resultSize * 2);
 
-        winrt::Windows::Foundation::Collections::IVector<hstring> unionedExtensionVector;
+        winrt::Windows::Foundation::Collections::IVector<hstring> unionedExtensionVector{ single_threaded_vector<hstring>() };
 
         for (const auto& filter : filters)
         {
@@ -370,6 +370,7 @@ namespace PickerCommon {
         }
         else if (unionChoices)
         {
+            // when filters not defined, "All files" category is the union of all extensions defined in FileTypeChoices
             FileTypeFilterData.push_back(AllFilesText);
             FileTypeFilterData.push_back(JoinExtensions(unionedExtensionVector.GetView()));
         }

test/StoragePickersTests/PickerCommonTests.cpp

@@ -237,6 +237,35 @@ namespace Test::PickerCommonTests
                 L"*.png;*.jpg;*.jpeg;*.bmp");
         }
 
+        TEST_METHOD(VerifyFilters_FileSavePickerWhenUnionChoicesExpectMatchingSpec)
+        {
+            // Arrange.
+            winrt::Microsoft::UI::WindowId windowId{};
+            winrt::Microsoft::Windows::Storage::Pickers::FileSavePicker picker(windowId);
+
+            picker.FileTypeChoices().Insert(
+                L"Documents", winrt::single_threaded_vector<winrt::hstring>({ L".txt", L".doc", L".docx" }));
+            picker.FileTypeChoices().Insert(
+                L"Pictures", winrt::single_threaded_vector<winrt::hstring>({ L".png", L".jpg", L".jpeg", L".bmp" }));
+
+            // Act.
+            PickerParameters parameters{};
+            parameters.CaptureFilterSpec(picker.FileTypeChoices().GetView(), true);
+
+            // Assert.
+            VERIFY_ARE_EQUAL(parameters.FileTypeFilterPara.size(), 3);
+
+            VERIFY_ARE_EQUAL(
+                std::wstring(parameters.FileTypeFilterPara[0].pszSpec),
+                L"*.txt;*.doc;*.docx");
+            VERIFY_ARE_EQUAL(
+                std::wstring(parameters.FileTypeFilterPara[1].pszSpec),
+                L"*.png;*.jpg;*.jpeg;*.bmp");
+            VERIFY_ARE_EQUAL(
+                std::wstring(parameters.FileTypeFilterPara[2].pszSpec),
+                L"*.txt;*.doc;*.docx;*.png;*.jpg;*.jpeg;*.bmp");
+        }
+
         TEST_METHOD(VerifyFilters_FileSavePickerWhenNoFileTypeChoicesDefinedExpectAsteriskSpec)
         {
             // Note that is is a different behavior than the UWP pickers, where FileTypeChoices are required.