List instead of array

Question

I currently have a function with output myResult a dictionary of array of byte. I want to convert it into a dictionary of list of byte since for each entry I may store more than 1 array of byte. What is the format to replace the array with a list and how do I add each array to the list. The current format is the following:

int img_sz = img0->width * img0->height * img0->nChannels;

array <Byte>^ hh = gcnew array<Byte> (img_sz);

Marshal::Copy( (IntPtr)img->imageData, hh, 0, img_sz );

Dictionary<String^,array< Byte >^>^ myResult = gcnew Dictionary<String^,array< Byte >^>(); 

myResult["OVERVIEW"]=hh;

Any help is appreciated.

David Yaw · Accepted Answer · 2012-07-17 22:07:49Z

1

I'm not entirely sure which one of these you're going for, so I'll answer them both.

`Dictionary<String^, List<Byte>^>^`

If you want to end up with Dictionary<String^, List<Byte>^>^, just call the List<T> constructor that takes an IEnumerable<T>, and add it to the dictionary as you are now.

Dictionary<String^,List<Byte>^>^ myResult = gcnew Dictionary<String^,List<Byte>^>(); 

myResult["OVERVIEW"] = gcnew List<Byte>(hh);

`Dictionary<String^, List<array<Byte>^>^>^`

If you want to end up with Dictionary<String^, List<array<Byte>^>^>^, you'll need to check the dictionary to see if it as a list for that key yet, add the list if not, and then add the new array to the list. Call this method with the various arrays and name of the list you want to store each of them in.

void AddToResults(Dictionary<String^, List<array<Byte>^>^>^ myResult, 
                  String^ key, 
                  array<Byte>^ hh)
{
    List<array<Byte>^>^ thisList;

    if(!myResult->TryGetValue(key, thisList))
    {
        thisList = gcnew List<array<Byte>^>();
        myResult->Add(key, thisList);
    }

    thisList->Add(hh);
}

edited Jul 17, 2012 at 22:07

answered Jul 17, 2012 at 19:25

David Yaw

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6 Comments

Hans Passant Over a year ago

He meant Dictionary<String^, List<array<Byte>^>^>

fmvpsenior Over a year ago

So if I have hh1 and hh2 to store in the list, how do i store them?

fmvpsenior Over a year ago

What's the difference between List<Byte>^ and List<array<Byte>^>^? I thought that List<Byte^> should be able to solve it.

David Yaw Over a year ago

Based on your previous questions, I know you're working with images here. The former is a single image, but stored in a list, rather than in an array. The latter is a list of images. From your original question, it wasn't entirely clear which one you were trying to do, so I answered both.

fmvpsenior Over a year ago

Can I add multiple images if i use List<Byte>^ and then nameoflist->Add(hh)?

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