93 lines
3.3 KiB
C++
93 lines
3.3 KiB
C++
// Copyright (c) Microsoft Corporation. All rights reserved.
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// Licensed under the MIT License.
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#pragma once
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namespace CalculatorApp
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{
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namespace Common
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{
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public
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ref class ValidSelectedItemConverter sealed : public Windows::UI::Xaml::Data::IValueConverter
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{
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public:
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ValidSelectedItemConverter()
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{
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}
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private:
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virtual Platform::Object
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^ Convert(
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Platform::Object ^ value,
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Windows::UI::Xaml::Interop::TypeName /*targetType*/,
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Platform::Object ^ /*parameter*/,
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Platform::String ^ /*language*/) = Windows::UI::Xaml::Data::IValueConverter::Convert
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{
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// Pass through as we don't want to change the value from the source
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return value;
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}
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virtual Platform::Object
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^ ConvertBack(
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Platform::Object ^ value,
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Windows::UI::Xaml::Interop::TypeName /*targetType*/,
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Platform::Object ^ /*parameter*/,
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Platform::String ^ /*language*/) = Windows::UI::Xaml::Data::IValueConverter::ConvertBack
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{
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if (value)
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{
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return value;
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}
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// Stop the binding if the object is nullptr
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return Windows::UI::Xaml::DependencyProperty::UnsetValue;
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}
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};
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public
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ref class ValidSelectedIndexConverter sealed : public Windows::UI::Xaml::Data::IValueConverter
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{
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public:
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ValidSelectedIndexConverter()
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{
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}
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private:
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virtual Platform::Object
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^ Convert(
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Platform::Object ^ value,
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Windows::UI::Xaml::Interop::TypeName /*targetType*/,
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Platform::Object ^ /*parameter*/,
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Platform::String ^ /*language*/) = Windows::UI::Xaml::Data::IValueConverter::Convert
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{
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// Pass through as we don't want to change the value from the source
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return value;
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}
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virtual Platform::Object
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^ ConvertBack(
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Platform::Object ^ value,
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Windows::UI::Xaml::Interop::TypeName /*targetType*/,
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Platform::Object ^ /*parameter*/,
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Platform::String ^ /*language*/) = Windows::UI::Xaml::Data::IValueConverter::ConvertBack
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{
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// The value to be valid has to be a boxed int32 value
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// extract that value and ensure it is valid, ie >= 0
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if (value)
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{
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auto box = dynamic_cast<Windows::Foundation::IPropertyValue ^>(value);
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if (box && box->Type == Windows::Foundation::PropertyType::Int32)
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{
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int index = box->GetInt32();
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if (index >= 0)
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{
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return value;
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}
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}
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}
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// The value is not valid therefore stop the binding right here
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return Windows::UI::Xaml::DependencyProperty::UnsetValue;
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}
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};
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}
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}
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