Nrthugu

I have class which derives from a collection which has a property MyString, i.e.

  public class CollectionItem

  {

    public bool MyBoolean { get; set; }



    public int MyInteger { get; set; }

  }



  public class MyCollection : List<CollectionItem>

  {

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]

    public string MyString { get; set; }



    public MyCollection()

    {

      MyString = "Hello";

    }

  }

This collection is part of a simple DummyControl, i.e.

  public class DummyControl : System.Windows.Forms.Control

  {

    protected override void OnPaint(PaintEventArgs e)

    {

      base.OnPaint(e);

      e.Graphics.FillRectangle(System.Drawing.Brushes.Yellow, e.ClipRectangle);

    }



    public DummyControl() 

    {

      MyCollection = new MyCollection();



      for (int i = 0; i < 3; i++)

      {

        CollectionItem item = new CollectionItem();

        item.MyInteger = i;

        item.MyBoolean = i > 1;

        MyCollection.Add(item);

      }

    }



    [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]

    public MyCollection MyCollection { get; set; }

  }

When I put this DummyControl on a Windows Form, everything is serialized as expected to the Form Designer except the MyString property - this is what I get:

  // 

  // dummyControl1

  // 

  this.dummyControl1.Location = new System.Drawing.Point(66, 62);

  collectionItem1.MyBoolean = false;

  collectionItem1.MyInteger = 0;

  collectionItem2.MyBoolean = false;

  collectionItem2.MyInteger = 1;

  collectionItem3.MyBoolean = true;

  collectionItem3.MyInteger = 2;

  this.dummyControl1.MyCollection.Add(collectionItem1);

  this.dummyControl1.MyCollection.Add(collectionItem2);

  this.dummyControl1.MyCollection.Add(collectionItem3);

  this.dummyControl1.Name = "dummyControl1";

  this.dummyControl1.Size = new System.Drawing.Size(338, 266);

  this.dummyControl1.TabIndex = 0;

  this.dummyControl1.Text = "dummyControl1";

Can anybody please tell me what more I have to do in order to have the MyString property serialized to the Form Designer?

Default CodeDom collection serializer doesn't serialize properties of the collection. You can create a custom serializer by deriving from CodeDomSerializer. Then register the custom serializer for your class:

[DesignerSerializer(typeof(MyCollectionSerializer), typeof(CodeDomSerializer))]

public class MyCollection : List<CollectionItem>

MyCollectionSerializer

This serializer serializes MyString property of MyCollection:

using System.CodeDom;

using System.ComponentModel;

using System.ComponentModel.Design.Serialization;

public class MyCollectionSerializer : CodeDomSerializer

{

    public override object Serialize(IDesignerSerializationManager manager, object value)

    {

        var baseSerializer = (CodeDomSerializer)manager.GetSerializer(

            typeof(MyCollection).BaseType, typeof(CodeDomSerializer));

        var statements = (CodeStatementCollection)baseSerializer.Serialize(manager, value);

        var property = TypeDescriptor.GetProperties(value)[nameof(MyCollection.MyString)];

        if (property.ShouldSerializeValue(value))

        {

            var targetObject = base.GetExpression(manager, value);

            var cpre = new CodePropertyReferenceExpression(targetObject, property.Name);

            var cpe = new CodePrimitiveExpression(property.GetValue(value));

            var cas = new CodeAssignStatement(cpre, cpe);

            statements.Add(cas);

        }

        return statements;

    }

} 

Then MyString property will be serialized as well:

// 

// dummyControl1

// 

...

this.dummyControl1.MyCollection.Add(collectionItem1);

this.dummyControl1.MyCollection.Add(collectionItem2);

this.dummyControl1.MyCollection.Add(collectionItem3);

this.dummyControl1.MyCollection.MyString = "Hello";

...