Hi

My goal is to extent the VS.NET button with some more custom
properties. I've created an inherented control which exposes a custom
class containing these new (sub)properties.

I ran into the following problem:

If I set the value for a subproperty, it is correctly serialized to
the sourcecode. Everthing is fine. After saving the project, I reset
the subproperty from the contextmenu. The value shown in the
PropertyGrid is resetted, but it is NOT serialized (removed from the
code). Changing the value is possible, only reset doesn't work.

Here is an example. It uses a custom TypeConverter and some
ShouldSerialize/Reset-functions:

public class EButton : Button {
  private Prop m_TestProp = new Prop(null);

  [TypeConverter(typeof(PropConverter))]
  public Prop TestProp {
     get {   return m_TestProp; }
     set {   m_TestProp = value; }
  }

  protected virtual bool ShouldSerializeTestProp() {
     return m_TestProp.Img != null;
  }

  protected virtual void ResetTestProp() {
     this.TestProp = new Prop(null);  //works
  }
}

[TypeConverter(typeof(PropConverter))]
public class Prop {
  public Prop(Image Img) {
     m_Img = Img;
  }

  private Image m_Img;

  [DefaultValue(null), NotifyParentProperty(true),]
  public Image Img {
     get { return m_Img; }
     set { m_Img = value; }
  }

  public void ResetImg(){
     this.Img = null;  // dont work, not serialized
  }
}

public class PropConverter : ExpandableObjectConverter {
  public override bool CanConvertTo(ITypeDescriptorContext context,
Type destinationType) {
     if (destinationType == typeof(InstanceDescriptor)) return true;

     return base.CanConvertTo(context, destinationType);
  }

  public override object ConvertTo(ITypeDescriptorContext context,
System.Globalization.CultureInfo culture, object value, Type
destinationType) {
     if (destinationType == typeof(InstanceDescriptor) && value is
Prop) {
        Prop NewProp = (Prop)value;

        ConstructorInfo CInfo = typeof(Prop).GetConstructor(new
Type[] { typeof(Image) });

        if (CInfo != null) return new InstanceDescriptor(CInfo, new
object[] { NewProp.Img });
     }
     return base.ConvertTo(context, culture, value, destinationType);
  }
}

steps:

- assign a new Image to the "TestProp -> Img" subproperty in the
designer
- new value shows up correctly and is serialized to the code
- save the project/sourcefile
- reset the "Img" property from the contextmenu (NOT the whole
"TestProp" property, only the subproperty "Img")
- displayed value for "Img" is properly resetted (null), but this
change wasn't serialized to the sourcecode

Why? What do i miss?

Sven