Objective c IKImageBrowserView:拖放错误

我正在使用IKImageBrowserView并获取。所以我应该使用nsurl而不是NSStrings/path。我现在已经将所有内容都更改为NSURL，但仍然得到相同的错误。我试着使用IKImageBrowserNSURLRepresentationType和NSURLPboardType，但这也不起作用。拖动照片时，控制台会一直显示：

__CFPasteBoardIssuseAndBoxextensionForPath:路径错误

我的数据结构如下所示：

@implementation MyImageObject

- (void) setPath:(NSURL *) path{
    if(myPath != path){
        myPath = path;
    }
}

- (NSString *)  imageRepresentationType{
    return IKImageBrowserPathRepresentationType;
}

- (id)  imageRepresentation{
    return myPath;
}

- (NSURL *) imageUID{
    return myPath;
}

并将图像浏览器写入到粘贴板：

- (NSUInteger) imageBrowser:(IKImageBrowserView *) aBrowser writeItemsAtIndexes:(NSIndexSet *) itemIndexes toPasteboard: (NSPasteboard *)pasteboard {

    NSUInteger index;

    //instantiate an array to store paths
    NSMutableArray *filesArray = [NSMutableArray array];

    //for each index...
    for(index = [itemIndexes firstIndex]; index != NSNotFound; index = [itemIndexes indexGreaterThanIndex:index]){

        //...get the path you want to add to the pasteboard
        id myDatasourceItem = [myImages objectAtIndex:index];

        //add it to your array
        [filesArray addObject:[myDatasourceItem imageUID]];
    }

    //declare the pasteboard will contain paths
    [pasteboard declareTypes:[NSArray arrayWithObjects:NSFilenamesPboardType,nil] owner:self];

    [pasteboard writeObjects:filesArray];

    //return the number of items added to the pasteboard
    return [filesArray count];
}

那么，有人知道我必须使用哪些类型，或者如何消除此错误消息吗