Question

在为ComboBoxItem提供一台显像仪时,你假定能够利用托String(TString)功能提供显示器。但这一功能从未被叫到,显示只是一个空白箱。

习俗二者:

class ComboboxItem : public winrt::implements<ComboboxItem, winrt::Windows::Foundation::IInspectable>
{
public:
    ComboboxItem() : m_text(L"Hello") {}

    hstring Text() { return m_text; }
    void Text(hstring const& value) { m_text = value; }

    winrt::Windows::Foundation::IInspectable Value() { return m_value; }
    void Value(winrt::Windows::Foundation::IInspectable const& value) { m_value = value; }

    hstring ToString() cons { return m_text; }    // This is never called

private:
    hstring m_text;
    winrt::Windows::Foundation::IInspectable m_value;
};

Adding to ComboBox:

comboxBox.Items().Append(winrt::make<ComboboxItem>());

失踪的“特别引诱”在ComboBox展示什么?

Answer 1

我在C#中执行,是因为这是我能够开展工作的唯一途径。

using Microsoft.UI.Xaml.Controls;

namespace App2CSharp
{
    internal class MyComboBoxItem : ComboBoxItem
    {
        public MyComboBoxItem()
        {
            Content = "TEST";
        }
    }
}

XAML:

<ComboBox x:Name="MyComboBox" Header="Colors" PlaceholderText="Pick a color" Width="200">
            <x:String>Blue</x:String>
            <x:String>Green</x:String>
            <x:String>Red</x:String>
            <x:String>Yellow</x:String>
            <ComboBoxItem>Gray</ComboBoxItem>
        </ComboBox>

而且

ComboBoxItem c = new MyComboBoxItem();
MyComboBox.Items.Add(c);

友情链接