Serializing Button class

[siddnair54]

I'm trying to serialize a button created at runtime.
But it throws an exception regarding the serializable attribute.
Is there any other way, how I can save the state of the Button?

[GaryTexmo]

Hmm, I can you post more details? I'm only really familiar with XML serialization, so if you're not doing that I'm not sure how much I can help, but I'll try.

Need more information though... a code snippet and the exception text would do nicely.

[siddnair54]

Actually i'm using Binary serialization.
Forget about the type of serialization. The real problem i'm facing is to make the Button class serializable.

The scenario is that, i'm creating a button at runtime. Inorder to save its state I have to serialize it. The code goes like this....

            try
            {
                Button b1 = new Button();
                this.Controls.Add(b1);
 
                FileStream fs = new FileStream("C:\\Serialize.binary",        FileMode.CreateNew);
                BinaryFormatter bf = new BinaryFormatter();
                bf.Serialize(fs, b1);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
 

When i run this code, it throws this exception...

Type 'System.Windows.Forms.Button' in Assembly 'System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' is not marked as serializable


I tried creating usercontrol but even that didn't work. it gives the same exception.

[GaryTexmo]

Hmm, the error message "not marked as serializable" seems to be the key. When you make something serializable for XML, you need the [Serializable] tag (or something similar) so perhaps that's it.

I just did some tests and it seems you need the [Serializable] tag to serialize things in this fashion. Button must not have that. I did try adding the tag to a new class that inherits from button, but that doesn't work either.

I'm not sure how you can do this... maybe you could make a wrapper class that exposed a string property that was a string representation of a button (like, name="blah";size="blah") and when set, it instantiated the correct button. There's gotta be a better way to do it though! I'll see if I can figure something out, or maybe someone else will have some insight. Google wasn't terribly helpful, but I might not have searched correctly.

[GaryTexmo]

I found this...

http://forum.codecall.net/c-programm...y-created.html

... it looks like they went with the wrapper solution.

Sorry I couldn't be of better help. Good luck!

[siddnair54]

@GaryTexmo
Its ok..

Even i tried wid the Wrapper class... but wid no results.
Created a custom class too...but it gives the same exception..
Please do reply if you get any insights to this.
Thanks.

[GaryTexmo]

By wrapper class, I mean mean a brand new class that doesn't expose the button as a public member, so it won't be serialized. Something like this...

[Serializable]
public class MyButton : UserControl
{
  private Button m_button = new Button();
 
  public class MyButton() { };
 
  // Expose public properties on m_button that you wish exposed
 
  public string ButtonProperties
  {
    get
    {
      return String.Format("Name={0};Text={1}, ...", m_button.Name, m_button.Text, ...);
    }
 
    set
    {
      // parse "value"
      // set properties on m_button depending on the data obtained from "value"
    }
  }
}

That's kind of what I meant. The actual button object is private and won't be serialized, but the public string will be, which will define a button via a text string. This should let you get button properties back, though honestly I'm not sure how this would work for events.

I feel like there *has* to be a better way to do this, but I honestly don't know. Hopefully that helps you at least in some way.

[Fr33dan]

Gary I'm afraid your solution won't work either because the button will still have to be serialized. By default in binary serialization (I've never worked with XML serialization) by all members public or private must will be serialized to store the object and then deserialized to recreate it.

In order to serialize a object like this properly you must write a subclass that implements the ISerializable interface. The ISerializable interface that allows you to define which members to serialize in a object and how to recreate the object from the serialized data (via a special constructor):

[Serializable]
    class MyButton:Button, ISerializable
    {
        public MyButton()
            : base()
        {
        }
 
        protected MyButton(SerializationInfo info, StreamingContext context):base()
        {
            this.Text = info.GetString("Text");
            this.Location = (Point)info.GetValue("Location",typeof(Point));
        }
 
        [SecurityPermissionAttribute(SecurityAction.Demand, 
        SerializationFormatter =true)]
        public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            info.AddValue("Text", this.Text);
            info.AddValue("Location", this.Location);
        }
 
    }
 

I've only serialized the text and location here but you can modify this to serialize whatever data you need to store (as long as what you store is serializable). Then you can use the now serializable MyButton class in place of the normal button.

More information on binary serialization is available here (The concepts I've expressed here are available under Custom Serialization): http://msdn.microsoft.com/en-us/libr...=VS.80%29.aspx

[GaryTexmo]

Excellent, thanks for posting that!

I didn't realize the binary serializer also serialized private members (the XML one does not), so good to know. I knew there had to be a better way to do it ;)

[siddnair54]

@Fr33dan
Ya..true....
But will this help to serialize other vital properties like the height, width, location etc. of the button?
Because when the user reruns the application, the button has to be recreated on the form. So these properties must be available.

[Fr33dan]

Yes this can be used to store whatever information you deem vital.

In my example I called info.AddValue to add the text of the button and the location and text but you could include width, height or color or absolutely anything you think should be preserved in serialization.

All you have to do is add it to the SerializationInfo object in the GetObjectData method and then pull it back out of the SerializationInfo object in the second constructor.

If you look in my example I call "info.AddData("Text",this.Text)" with tells the system that you want to store this.Text linked to the string "Text". Then in my constructor I used info.GetString("Text") to pull the information back out and set it on the recreated instance.

The only limitation of this is if you try to add an object that is not serializable to the SerializationInfo. But if you really needed it to work you could go in and do the same thing your doing for the Button to that object.

[siddnair54]

@Fr33dan
Hey thanks..
I'll try this out and get back to you.
Thanks for your response.