Is it possible to store controls(Panel) as object, serialize it and store it as a file?

Question

The topic says it all.

Using Compact Framework C#

I'm tiling (order/sequence is important) some images that i download from an url, into a Panel(each image is a PictureBox). This can be a huge process, and may take some time.

Therefor i only want the user to download the images and tile them once. So the next time the user uses the Tile Application, the Panel that was created the first time is already stored in a file and is loaded from that file.

So what i want is a method to store a Panel as a file.

Is this possible, or do you think i should do it another way?

I've tried something like this:

            BinaryWriter panelStorage = new BinaryWriter(new FileStream("imagePanel.panel", FileMode.OpenOrCreate, FileAccess.Write, FileShare.None));
            Byte[] bImageObject = new Byte[20000];
            bImageObject = (byte[])(object)this.imagePanel;
            panelStorage .Write(bMapObject);
            panelStorage .Close();

But the casting was not very legal :P

"InvalidCastException"

Can anyone help me with this problem?

Thank you in advance!

Answer 1

Yes, your code will throw, you cannot cast a Control object to byte[]. That kind of conversion requires serialization, the kind performed by BinaryFormatter. Trouble is: the Control class and its decedents are not serializable, they don't have the [Serializable] attribute.

The Control class is a complicated mother, it has hundreds of private fields. A lot of those fields have values that are generated at runtime, often by interoperating with the native Windows window. While serializing them is somewhat possible, deserializing is not. Reconstructing the Control object requires the native window to be reconstructed as well. And it has a lot of state itself, the kind that's set by sending it a bunch of message. Regenerating those messages isn't practical.

This doesn't leave you with a lot of attractive options. Serializing a UI is possible, the Windows Forms designer and WPF XAML does it. But these are very large chunks of code, not easily embedded in your program.

Aim lower, don't try to serialize the entire control. Just some of its properties, like Size and Location, and you'll have a shot at making this work.

Answer 2

ResX files serialize several properties of the control. Perhaps you can use those?

Answer 3

I wouldn't serialize the control if I were you. I'd instead serialise the data that goes into the control. There are a couple of reasons.

Firstly, it's easier. You can take whatever data you are putting in (images) and put them into a custom MyPanel class or whatever. Store information about how they are manipulated in there too, and then you can serialise that class, and it's done.

The second reason is that if you want to change how the data is displayed or used at a later date, you have a lot more freedom. You can use it in other ways, or with other applications and controls without any real effort on your part.