Question

我遇到了C ++ / CX的问题。我试图创建一个实际上是其他类的集合的类。该类在头文件中声明：

#pragma once
namespace AdeptlyAdaptiveLayout
{

   public ref class NewsItem sealed
   {
   public:
    NewsItem(int init_Id, Platform::String^ init_Category, Platform::String^ init_Headline, Platform::String^ init_Subhead, Platform::String^ init_DateLine, Platform::String^ Image);
    property int Id;
    property Platform::String^ Category;
    property Platform::String^ Headline;
    property Platform::String^ Subhead;
    property Platform::String^ DateLine;
    property Platform::String^ Image;
   };

   public ref class NewsItemCollection sealed
   {
   public:
    Platform::Collections::Vector<NewsItem> getNewsItems();
   };
}

这是源文件

#include "pch.h"
#include "NewsItem.h"

using namespace Platform;
using namespace Platform::Collections;

namespace AdeptlyAdaptiveLayout
{
    NewsItem::NewsItem(int init_Id,
        String^ init_Category,
        String^ init_Headline,
        String^ init_Subhead,
        String^ init_DateLine,
        String^ init_Image)
    {
        Id = init_Id;
        Category = init_Category;
        Headline = init_Headline;
        Subhead = init_Subhead;
        DateLine = init_DateLine;
        Image = init_Image;
    }

    Vector<NewsItem> NewsItemCollection::getNewsItems()
    {
        Vector<NewsItem> temp;

        temp.Append(*ref new NewsItem(1, "Financial", "Lorem Ipsum", "doro sit amet", "Nunc tristique nec", "Assets/Financial1.png"));
        temp.Append(*ref new NewsItem(2, "Financial", "Etiam ac felis viverra", "vulputate nisl ac, aliquet nisi", "tortor porttitor, eu fermentum ante congue", "Assets/Financial2.png"));
        temp.Append(*ref new NewsItem(3, "Financial", "Integer sed turpis erat", "Sed quis hendrerit lorem, quis interdum dolor", "in viverra metus facilisis sed", "Assets/Financial3.png"));
        temp.Append(*ref new NewsItem(4, "Financial", "Proin sem neque", "aliquet quis ipsum tincidunt", "Integer eleifend", "Assets/Financial4.png" ));
        temp.Append(*ref new NewsItem(5, "Financial", "Mauris bibendum non leo vitae tempor", "In nisl tortor, eleifend sed ipsum eget", "Curabitur dictum augue vitae elementum ultrices", "Assets/Financial5.png" ));

        temp.Append(*ref new NewsItem(6, "Food", "Lorem ipsum", "dolor sit amet", "Nunc tristique nec", "Assets/Food1.png" ));
        temp.Append(*ref new NewsItem(7, "Food", "Etiam ac felis viverra", "vulputate nisl ac, aliquet nisi", "tortor porttitor, eu fermentum ante congue",  "Assets/Food2.png" ));
        temp.Append(*ref new NewsItem(8,"Food", "Integer sed turpis erat", "Sed quis hendrerit lorem, quis interdum dolor", "in viverra metus facilisis sed","Assets/Food3.png" ));
        temp.Append(*ref new NewsItem(9, "Food","Proin sem neque", "aliquet quis ipsum tincidunt", "Integer eleifend", "Assets/Food4.png" ));
        temp.Append(*ref new NewsItem(10, "Food", "Mauris bibendum non leo vitae tempor", "In nisl tortor, eleifend sed ipsum eget", "Curabitur dictum augue vitae elementum ultrices", "Assets/Food5.png" ));

        return temp;
    }

}

问题是我一直有这个错误消息＆＃34; class＆＃39; AdeptlyAdaptiveLayout :: NewsItem＆＃39;没有合适的拷贝构造函数＆＃34;。我不知道自己做错了什么。你能告诉我一个线索吗？

Answer 1

好的，我现在找到了答案。我已经将类型从Vector更改为IVector，显式创建了复制构造函数，并在实现中添加了几个更改。以下是标题和源代码中已更改的代码。

部首：

<div class="pie_nut" id="pieChartContainer">
    <canvas id="pieChart" height="5" width="6"></canvas> 
</div>

$('#pieChartContainer').html(''); //remove canvas from container
$('#pieChartContainer').html('<canvas id="pieChart" height="5" width="6"></canvas>'); //add it back to the container

来源：

namespace AdeptlyAdaptiveLayout
{

    public ref class NewsItem sealed
    {
    public:
        NewsItem(int init_Id, Platform::String^ init_Category, Platform::String^ init_Headline, Platform::String^ init_Subhead, Platform::String^ init_DateLine, Platform::String^ Image);
        NewsItem(NewsItem^ obj);
        property int Id;
        property Platform::String^ Category;
        property Platform::String^ Headline;
        property Platform::String^ Subhead;
        property Platform::String^ DateLine;
        property Platform::String^ Image;
    };

    public ref class NewsItemCollection sealed
    {
    public:
        Windows::Foundation::Collections::IVector<NewsItem^>^ getNewsItems();
    };
}

但是，我仍然不明白为什么会这样。我想我会对此进行深入的研究。

Answer 2

当您为构造函数提供此构造函数签名时：

NewsItem(int init_Id, Platform::String ....

...编译器将不再为您合成默认ctors。在这种情况下，您现在需要自己指定它们。

https://msdn.microsoft.com/en-us/library/s16xw1a8.aspx

如果声明了任何非默认构造函数，则编译器不会提供默认构造函数

C ++ / CX没有合适的复制构造函数

2 个答案: