Hi,

I want to bind an EntityCollection to a Win-Forms DataGrid. Each entity of the collection contains another entity by relation (m:1). My aim is to bind a field of the inner entity to the grid.

I tried as MappingName for the DataGridTextBoxColumn

"PropertyNameOfInnerEntity.PropertyName"

, but there was no column shown.

Have I done anything wrong? If not, is there a way to handle such situations?

Thanks for help.

Al

You could add a property to the derived entity class and that property calls into the related entity's property.

Could you expand more on this?

I've got a Northwinds Product/Category entity collection that I'm trying to display in a datagrid.

Here's my code:

Private myProducts As EntityCollection

Private Sub frmProducts_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    '
End Sub

Private Sub btnLoad_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoad.Click
    LoadProducts()
    Bind()
End Sub

Private Sub LoadProducts()
    Dim adapter As DataAccessAdapter
    Try
        adapter = New DataAccessAdapter

        myProducts = New EntityCollection(New ProductEntityFactory)
        Dim prefetchPath As IPrefetchPath2 = New PrefetchPath2(CType(EntityType.ProductEntity, Integer))
        prefetchPath.Add(ProductEntity.PrefetchPathCategory)

        adapter.FetchEntityCollection(myProducts, Nothing, prefetchPath)
    Catch ex As Exception
    Finally
        adapter.CloseConnection()
    End Try
End Sub

Private Sub Bind()
    dg.TableStyles.Clear()
    dg.TableStyles.Add(BuildDataGridTableStyle)
    dg.DataSource = myProducts
End Sub

Private Function BuildDataGridTableStyle() As DataGridTableStyle
    Dim myTableStyle As New DataGridTableStyle

    '--- Col 1 ---
    Dim myCol1 As New DataGridTextBoxColumn
    With myCol1
        .HeaderText = "Product ID"
        .MappingName = "ProductID"
        .Width = 100
    End With
    myTableStyle.GridColumnStyles.Add(myCol1)

    '--- Col 2 ---
    Dim myCol2 As New DataGridTextBoxColumn
    With myCol2
        .HeaderText = "Product Name"
        .MappingName = "ProductName"
        .Width = 100
    End With
    myTableStyle.GridColumnStyles.Add(myCol2)

    '--- Col 3 ---
    Dim myCol3 As New DataGridTextBoxColumn
    With myCol3
        .HeaderText = "Category ID"
        .MappingName = "CategoryID"
        .Width = 100
    End With
    myTableStyle.GridColumnStyles.Add(myCol3)

    '--- Col 4 ---
    Dim myCol4 As New DataGridTextBoxColumn
    With myCol4
        .HeaderText = "Category Name"
        .MappingName = "Category.CategoryName"
        ''''''''.MappingName = "Category"
        ''''''''.MappingName = "CategoryName"
        .Width = 100
    End With

    myTableStyle.GridColumnStyles.Add(myCol4)

    Return myTableStyle
End Function

Everything works great except for the Category.CategoryName column. How do I get the related entity's fields to display in the grid?

Thanks for your help!

For demo users, the derived entity classes for adapter aren't available, so adding that code to the current entities is a bit problematic. This will be addressed in hte 1.0.2004.2 release. In the meantime, use a typed list for this.