展開可能なプロパティのサポート (xamPropertyGrid)

Public Class CustomTypeConverter
  Inherits TypeConverter
  Public Overrides Function ConvertTo( _
    context As ITypeDescriptorContext, _
    culture As CultureInfo, _
    value As [Object], _
    destinationType As Type) As Object
    Return "Employee's Collection"
  End Function
End Class
…
<TypeConverter(GetType(CustomTypeConverter))> _
Public Property Customers() As List(Of Customer)
  Get
    Return m_Customers
  End Get
  Set
    m_Customers = Value
  End Set
End Property
Private m_Customers As List(Of Customer)

public class CustomTypeConverter : TypeConverter
{
  public override object ConvertTo(
    ITypeDescriptorContext context,
    CultureInfo culture,
    Object value,
    Type destinationType)
  {
    return "Employee's Collection";
  }
}
…
[TypeConverter(typeof(CustomTypeConverter))]
public List<Customer> Customers
{
  get; set;
}

Public Class Employee
  Public Property FirstName() As String
    Get
      Return m_FirstName
    End Get
    Set
      m_FirstName = Value
    End Set
  End Property
  Private m_FirstName As String
  Public Property LastName() As String
    Get
      Return m_LastName
    End Get
    Set
      m_LastName = Value
    End Set
  End Property
  Private m_LastName As String
End Class
Public Class EmployeePropertyDescriptor
  Inherits PropertyDescriptor
  Private collection As EmployeeCollection
  Private index As Integer
  Public Sub New(col As EmployeeCollection, i As Integer)
    Me.collection = col
    Me.index = i
  End Sub
  Public Overrides ReadOnly Property DisplayName() As String
    Get
      Dim emp As Employee = Me.collection(index)
      Return emp.FirstName & " " & Convert.ToString(emp.LeftName)
    End Get
  End Property
End Class
Public Class EmployeeCollection
  Inherits List(Of Employee)
  Implements ICustomTypeDescriptor
  Public Function GetProperties() As PropertyDescriptorCollection
    Dim pds As New PropertyDescriptorCollection(Nothing)
    For i As Integer = 0 To Me.Count - 1
      Dim pd As New EmployeePropertyDescriptor(Me, i)
      pds.Add(pd)
    Next
    Return pds
  End Function
End Class

public class Employee
{
  public string FirstName { get; set; }
  public string LastName { get; set; }
}
public class EmployeePropertyDescriptor : PropertyDescriptor
{
  private EmployeeCollection collection;
  private int index;
  public EmployeePropertyDescriptor(EmployeeCollection col, int i)
  {
    this.collection = col;
    this.index = i;
  }
  public override string DisplayName
  {
    get
    {
      Employee emp = this.collection[index];
      return emp.FirstName + " " + emp.LeftName;
    }
  }
}
public class EmployeeCollection : List<Employee>, ICustomTypeDescriptor
{
  public PropertyDescriptorCollection GetProperties()
  {
    PropertyDescriptorCollection pds = new PropertyDescriptorCollection(null);
    for (int i = 0; i < this.Count; i++)
    {
      EmployeePropertyDescriptor pd = new EmployeePropertyDescriptor(this, i);
      pds.Add(pd);
    }
    return pds;
  }
}