Myujth

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";
...