Best way to store sets of images for Windows Forms

Question

I am developing a windows forms applications and I will use sets of images (think icons). Depending on the theme, different sets of images must be chosen (I will later draw them using a Bitmap).

I was thinking of storing the images in separate files (archive files ? dlls ?) and then loading them at runtime from the main application. What would be the most effective way to do this ?

Thank you for reading.

score 3 · Answer 1 · answered Sep 03 '11 at 17:37

3

I shall answer this considering few scenarios.

Does this images change often? Then go for directory based approcach, where store it in a directory and load it up. May be you can have an xml having the names of these files to load. So name change in the files (images), just change xml.
These files never changes? Then just embed those as a resources, such a way it will be embedded into your exe/dll and none can corrupt the images.

Normally i have seen folks not doing embedding.

answered Sep 03 '11 at 17:37

Zenwalker

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How do I embed the images as resources and create a separate resource for each theme ? – csq Sep 03 '11 at 17:38
2

In visual studio, go to project properties and to resources. There select image and add. Play a bit more with VS ;) – Zenwalker Sep 03 '11 at 17:40
Then how will I use the images in another project ? – csq Sep 03 '11 at 17:42
Make those resources as public modifiers. you can just reference the assembly in any project and start using those images. But just to do this, you wish to embed them? I thought you wud just use it in the same assembly. Still no harm/wrong. But why dont you just use directory approach? That way you could reduce assembly reference and face image files corruption/deletion problem. – Zenwalker Sep 03 '11 at 17:46

score 0 · Answer 2 · answered Sep 10 '11 at 06:24

Did you think about using resx files (resource files)? This way, you can embed any images (icons), or whatever you like and decide to load only the resource file that are needed based on your theme (resource files can be named based on your themes names). Seems like the same problem encountered when localizing, isnt it? But to know if it is the best way of doing it (performance, memory, etc.), I can't tell.

havardhu · Answer 3 · 2011-09-10T09:06:41.017

Not sure if you got the answer you were looking for. Here's a step-by-step to create a resource dll

Create a new project in visual studio, class library
Add your resources (pictures) to the project (Add existing item)
For each resource, in the properties window, set Build Action to Embedded resource
Compile the library, produces a dll
In your winforms application, you can now load this assembly at runtime (Code #1)
Load the resource stream that you want and save it to a Bitmap object (Code #2)

Code #1

Assembly ambly = Assembly.LoadFile(pathToDll);

Code #2

BitMap bitMap;
// where "ns" is the default namespace of the resource project    
using (Stream resourceStream = ambly.GetManifestResourceSream("ns.image.jpg"))
{
      bitMap = BitMap.FromStream(resourceStream);
}

These are the basic techniques used for embedding resources and loading them at runtime.

Now, since you're thinking of having different themes, and store the resources for each theme in different libraries, you should have an interface that specifies some sort of resource manager, defined in your main application.

An example

interface IThemeResourceProvider
{
     Stream LoadBigLogo();
     Stream LoadSmallLogo();
}

Then implement that interface in your resource library

public class ThemeResourceProvider : IThemeResourceProvider
{
    public Stream LoadBigLogo()
    {
         Assembly ambly = Assembly.GetExecutingAssembly();
         return ambly.GetManifestResourceStream("namespace.image.jpg");
    }

    (...)
}

Finally, instead of loading the resource directly in your main application, you instantiate the IThemeResourceProvider found in the resource library

 Assembly assembly = Assembly.LoadFile(pathToDll);

 var results = from type in assembly.GetTypes()
               where typeof(IThemeResourceProvider).IsAssignableFrom(type)
               select type;

Now you have an IEnumerable<Type> in that list. Typically, you'd only have one, but using this approach you could also host multiple sets of resources, and implement multiple IThemeResourceProviders in the same resource dll. You could e.g. identify each IThemeResourceProvider with a name, either as a property, or using a custom [Attribute] decoration on your various implementations. I'll leave the rest up to you to figure out.

But here's how to instantiate the IThemeResourceProviders in your list

foreach (var providerType in results)
{
     var constructorInfo = providerType.GetConstructor(Type.EmptyTypes);
     IThemeResourceProvider provider = constructorInfo.Invoke(null);
}

And finally, using one of these providers to get a bitmap:

BitMap bitMap;
using (Stream resourceStream = provider.LoadBigLogo())
{
      bitMap = BitMap.FromStream(resourceStream);
}

Best way to store sets of images for Windows Forms

3 Answers3