How to assign class property as display data member in datagridview - vb.net

Question

I am trying to display my data in datagridview. I created a class with different property and used its list as the datasource. it worked fine. but I got confused how to do that in case we have nested class.
My Classes are as follows:
class Category
property UIN as integer
property Name as string
end class
class item
property uin as integer
property name as string
property mycategory as category
end class
my data list as follows:
dim myDataList as list(of Item) = new List(of Item)
myDataList.Add(new Item(1,"item1",new category(1,"cat1")))
myDataList.Add(new Item(2,"item2",new category(1,"cat1")))
myDataList.Add(new Item(3,"item3",new category(1,"cat1")))
myDataList.Add(new Item(4,"item4",new category(2,"cat2")))
myDataList.Add(new Item(5,"item5",new category(2,"cat2")))
myDataList.Add(new Item(6,"item6",new category(2,"cat2")))
Now I binded the datagridview control like:
DGVMain.AutoGenerateColumns = False
DGVMain.ColumnCount = 3
DGVMain.Columns(0).DataPropertyName = "UIN"
DGVMain.Columns(0).HeaderText = "ID"
DGVMain.Columns(1).DataPropertyName = "Name"
DGVMain.Columns(1).HeaderText = "Name"
DGVMain.Columns(2).DataPropertyName = "" **'here i want my category name**
DGVMain.Columns(2).HeaderText = "category"
DGVMain.datasource = myDataList
DGVMain.refresh()
I have tried using mycategory.name but it didn't worked. What can be done to get expected result? Is there any better idea other than this to accomplish the same task?
Edited My question as per comment:
I have checked the link given by u. It was nice n very usefull. Since the code was in c# i tried to convert it in vb. Everything went good but failed at a point of case sensitive and next one is that i had my nested class name itemcategory and my property name was category. there it arouse the problem. it didn't searched for category but it searched for itemcategory. so confused on it. My Code as follows:
Private Sub DGVMain_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles DGVMain.CellFormatting
Dim DGVMain As DataGridView = CType(sender, DataGridView)
e.Value = EvaluateValue(DGVMain.Rows(e.RowIndex).DataBoundItem, DGVMain.Columns(e.ColumnIndex).DataPropertyName)
End Sub
Private Function EvaluateValue(ByRef myObj As Object, ByRef myProp As String) As String
Dim Ret As String = ""
Dim Props As System.Reflection.PropertyInfo()
Dim PropA As System.Reflection.PropertyInfo
Dim ObjA As Object
If myProp.Contains(".") Then
myProp = myProp.Substring(0, myProp.IndexOf("."))
Props = myObj.GetType().GetProperties()
For Each PropA In Props
ObjA = PropA.GetValue(myObj, New Object() {})
If ObjA.GetType().Name = myProp Then
Ret = EvaluateValue(ObjA, myProp.Substring(myProp.IndexOf(".") + 1))
Exit For
End If
Next
Else
PropA = myObj.GetType().GetProperty(myProp)
Ret = PropA.GetValue(myObj, New Object() {}).ToString()
End If
Return Ret
End Function

Answer 1

I'd just add a property to item called CategoryName that returns Category.Name and use that.
The Category is part of the Item, but that doesn't mean that you always have to give access to the whole Category to outside classes, just give access to the bits that they need access to at that time as to maximize encapsulation and minimize interdependencies.
Edit: In response to your comment
If you don't want to create the properties as mentioned in my answer above I don't think there is any real solution but you can use the 'CellFormatting' event to sort of get it to work where you set the DataPropertyName to a special identifier and then in the CellFormatting event handler you look up the real value to display. You can find an example of that here, look for tkrasinger's post (or AlexHinton's if you want to use reflection).

Answer 2

Public Class Category
Dim uni As Integer
Dim name As String
Public Sub New(ByVal i As Integer, ByVal n As String)
Me.UIN = i
Me.name = n
End Sub
Public Sub New()
End Sub
Property UIN() As Integer
Get
Return uni
End Get
Set(ByVal value As Integer)
uni = value
End Set
End Property
Property Names() As String
Get
Return Me.name
End Get
Set(ByVal value As String)
Me.name = value
End Set
End Property
**Public Overrides Function ToString() As String
Return name.ToString()
End Function**
End Class
Public Class item
Dim uni As Integer
Dim name As String
Dim category As New Category()
Property UIN() As Integer
Get
Return uni
End Get
Set(ByVal value As Integer)
uni = value
End Set
End Property
Property Names() As String
Get
Return Me.name
End Get
Set(ByVal value As String)
Me.name = value
End Set
End Property
Property mycategory() As Category
Get
Return Me.category
End Get
Set(ByVal value As Category)
Me.category = value
End Set
End Property
Public Sub New(ByVal i As Integer, ByVal nm As String, ByVal ct As Category)
Me.UIN = i
Me.Names = nm
Me.mycategory = ct
End Sub
End Class
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim myDataList As List(Of item) = New List(Of item)
myDataList.Add(New item(1, "item1", New Category(1, "cat1")))
myDataList.Add(New item(2, "item2", New Category(1, "cat1")))
myDataList.Add(New item(3, "item3", New Category(1, "cat1")))
myDataList.Add(New item(4, "item4", New Category(2, "cat2")))
myDataList.Add(New item(5, "item5", New Category(2, "cat2")))
myDataList.Add(New item(6, "item6", New Category(2, "cat2")))
DGVMain.AutoGenerateColumns = False
DGVMain.ColumnCount = 3
DGVMain.Columns(0).DataPropertyName = "UIN"
DGVMain.Columns(0).HeaderText = "ID"
DGVMain.Columns(1).DataPropertyName = "Names"
DGVMain.Columns(1).HeaderText = "Name"
**DGVMain.Columns(2).DataPropertyName = "mycategory"**
DGVMain.Columns(2).HeaderText = "Category"
DGVMain.datasource = myDataList
DGVMain.refresh()
End Sub