Unable to set valuemember/display member to bind combobox - vb.net

Question

I'm having trouble adding dynamically a combo box column to my datagridview (before you ask, yes it must be dynamic and not done in editor).
The main feature is that the combobox cell is different for each row, so it must be done using combo box cell. checkedRows is a datatable.
Name of the datagridview is editCameraTable. It already has a few columns at this point:
'create new column
Dim resComboColumn As New DataGridViewComboBoxColumn _
With {.HeaderText = "Resolution", .ReadOnly = False, .DisplayIndex = 7, .Name = "Resolution", _
.DisplayMember = "Name", .ValueMember = "ID", .DataPropertyName = "ID"}
'add combo box column
EditCameras.editCameraTable.Columns.Insert(17, resComboColumn)
addResCmbBox(checkedRows, resComboColumn)
Pretty straight forward. You'll notice I have the value member, dataproperty name, etc. Here's the addResCmbBox definition:
Public Function addResCmbBox(ByRef DT As DataTable, column As DataGridViewComboBoxColumn)
Dim resolutions As String()
'for each camera
For i As Integer = 0 To DT.Rows.Count - 1
Dim camera As camera = convertDTtoCam(DT, i)
'get the resarray
Select Case DT.Rows(i).Item("Maker").ToString.ToLower
Case "acti"
resolutions = ACTi.GetResArray(camera)
Case Else
resolutions = ACTi.GetResArray(camera)
End Select
'add items to combobox list
Dim comboCell As New DataGridViewComboBoxCell
comboCell.DataSource = resolutions
For j As Integer = 0 To resolutions.Length - 1
'set to current resolution value
If resolutions(j).TrimStart("N") = camera.res Then
comboCell.Value = resolutions(j)
End If
Next
comboCell.DisplayMember = "Name"
comboCell.ValueMember = "ID"
EditCameras.editCameraTable("Resolution", i) = comboCell
Next
Return Nothing
End Function
camera is a structure. I have no problems until I get to the displayMember and value member problem, i.e. the last line starting with "editcameras.editcameratable...".
When doing so, the exception of "The Field Name does not exist" pops up. If I don't assign the displayMember and valueMember, I have no problems. But, I can't get the value selected in the comboBox (it comes back as Null). At runtime, the combobox column has the valuemember and display name as "ID" and "Name".
How can I bind this comboboxcell to the row so that I can later get it's selected value?
UPDATE:
I did as was commented, and created a struct/class that was meant to be the resolution property:
Public Class ResolutionStruct
Property Name As String
Property ID As String
End Class
And within the loop I create a list of this class, and assign the values to it:
Dim resolutionList As New List(Of ACTi.ResolutionStruct)
For j As Integer = 0 To resolutions.Length - 1
Dim resClass As New ACTi.ResolutionStruct
resClass.Name = resolutions(j)
resClass.ID = resolutions(j)
resolutionList.Add(resClass)
Next
'set combocell values
comboCell.DisplayMember = "Name"
comboCell.ValueMember = "ID"
comboCell.DataSource = resolutionList
EditCameras.editCameraTable("Resolution", i) = comboCell
However, the comboboxCell doesn't show any value when it drops down. So, now I've bound the values but it shows nothing. Is there anything else I should be doing so that I get both the holy combo of seeing the values I'm picking AND having them be bound to the data grid view? :D
UPDATE 2
So, mea culpa. I was adding the combobox cell to the wrong column!
So now, it is showing the values. I click a value, and try to grab the selected value as as string:
Dim cmbbox2 As DataGridViewComboBoxCell = editCameraTable("Resolution", i)
resolution(i) = cmbbox2.Selected.ToString()
But it still says it's a null value! Mid build I checked the combobox props. IN fact "selected" is a boolean as false. It has no value, says it has no items as well. Any ideas on why it says it is null?
UPDATE3:
I recently resorted a different column in the table, and the values from the combo box are cleared! I guess it's really never being attached/bound in the first place.
UPDATE4:
Fixed it!!
Apparently this line:
editCameraTable.Sort(editCameraTable.Columns("ID"), System.ComponentModel.ListSortDirection.Ascending)
Caused the table to freak out! I can now get the value (woohoo!)

Answer 1

Right, I'll try to explain this shortly:
DisplayMember and ValueMember are supposed to be set using properties. For example you create a class containing Name and ID
Public Class Test
Property Name as String
Property ID as String
End Class
Create a few of these objects and put them in a list. Set the list as the datasource to the combobox. Now you can access the DisplayMember and ValueMember as you have written it in your code. Value would be the ID and SelectedItem would be the entire class.
What you are doing now is that you are adding a list of strings to the combobox. A String does not contain the Property Name nor ID, so naturally you can't fetch them. See it like this:
To be able to use Value and/or DisplayMember you need to be able to fetch the Property by yourself. In this case:
resolutions(j).Name
or
resolutions(j).ID
This does not work.
But for example you would be able to do this:
resolutions(j).Length
So You would be able to do this, which would display the Length in the combobox:
Combobox.DisplayMember = "Length"
To currently get the value you would have to do:
Combobox.SelectedItem.ToString()
But since you have it in a combobox column My guess is that this won't cut it since you can't fetch the value from the DataGridView.
EDIT: You are still doing this right?
<DataGridView>.Item("Resolution", i) = comboCell
Otherwise you will have empty comboboxes.
EDIT2: No need to fetch value from Combobox, get it from Grid cell instead:
<DataGridView>.Item("Resolution", i).Value
When creating the columns don't forget to set a defaultvalue to the combobox, otherwise it might be Nothing:
comboCell.DisplayMember = "Name"
comboCell.ValueMember = "ID"
comboCell.Value = resolutions(0)