c# - List expander in property grid , with genric ICustomTypeDescriptor -

i have generic class (parameters.cs) implements interface: icustomtypedescriptor.

i use generic class several different classes, 1 of this:

    private parameters<class1> _class1parameters;      public parameters<class1> class1parameters     {         { return _class1parameters; }         set { _class1parameters= value; }     } 

class1.cs:

public class class1 {     private list<position> _pos = new list<position>();      public list<position> pos     {         { return _pos ; }         set { _pos = value; }     }        //other variables } 

position class:

public class position {     public string name { get; set; }     public double position { get; set; } } 

right list displayed 3 points in propertygrid ("...").

i want displayed expander ("+"), how can through icustomtypedescriptor?

edit:

i tried putting [typeconverter(typeof(expandableobjectconverter))] on pos list, did not help.

finally managed make through site:

customized display of collection data in propertygrid