使用C＃的Windows Phone 7.5 appName.dll中发生类型'System.InvalidCastException'的未处理异常

Question

Does anyone know the proper way to cast itemCollection.GetEnumerator()?

For some reasons, return itemCollection.GetEnumerator(); works fine in windows phone 8, but doesn't work in windows phone 7.5 It asked me to explicity cast it, but I'm not sure what is the proper way. Does anyone know?

public class ItemCollection : IEnumerable<Object>
{
    private System.Collections.ObjectModel.ObservableCollection<Item> itemCollection = new System.Collections.ObjectModel.ObservableCollection<Item>();

    public IEnumerator<Object> GetEnumerator()
    {
        //return itemCollection.GetEnumerator();
        IEnumerator<Object> test = (IEnumerator<Object>)itemCollection.GetEnumerator();

        return test;
    }

    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }

    public void Add(Item item)
    {
        itemCollection.Add(item);
    }
}

Answer 1

我不确定，请尝试一下

IEnumerator<Object> test = new IEnumerator<Object>(itemCollection.GetEnumerator());

Answer 2

另外，试试这个

return itemCollection.Cast<object>()

Answer 3

hmm it not clear to me why you want to do this: wouldn't it be better to just do this:

public class ItemCollection : System.Collections.ObjectModel.ObservableCollection<Item>
{
}