VB.NET - Cannot bind to the new display member - vb.net

Question

I'm trying to assign the DataSource for a ComboBox that will allow the user to select a member. I'm receiving this error when run my application:
Cannot bind to the new display member.
Parameter name: newDisplayMember.
Here's my code:
Private Sub StartScreen_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'GetAllELData()
ddlMember.DataSource = GetMemberList()
ddlMember.DisplayMember = "DisplayName"
ddlMember.ValueMember = "ID"
End Sub
Private Function GetMemberList() As List(Of Member)
Dim rval = New List(Of Member)
Dim dv As DataView = New DataView
Dim myConnString = ConfigurationSettings.AppSettings("ConnString")
Try
dv = SqlHelper.ExecuteDataset(myConnString, CommandType.StoredProcedure, "spGetData").Tables(0).DefaultView
Catch ex As Exception
MessageBox.Show(ex.Message, "Database Error", MessageBoxButtons.OK)
End Try
For Each row As DataRowView In dv
Dim mbrNum As String = row.Item("IMMBR_CD").ToString()
Dim mbrName As String = System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(row.Item("IMMBR_NM20").ToLower())
Dim mbrState As String = row.Item("IMMBR_ST").ToString()
'assigns the member data to the list of members
rval.Add(New Member(mbrNum, mbrName, mbrState))
Next
Return rval
End Function
And then my class definition:
Public Class Member
Public ID As String
Public Name As String
Public State As String
Public DisplayName As String
Public Sub New(ByVal i As String, ByVal n As String, ByVal s As String)
ID = i
Name = n
State = s
DisplayName = ID & " - " & Name & ", " & State
End Sub
Public Overrides Function ToString() As String
Dim rval As String = ID & " - " & Name & ", " & State
Return rval
End Function
Public Function GetID() As String
Return ID
End Function
Public Function GetName() As String
Return Name
End Function
Public Function GetState() As String
Return State
End Function
End Class
I don't know why I'm getting the error. The application correctly loads the member as intended and works just fine once I click "Continue" on the error popup. Everything I've found about the error is for people passing a table as their DataSource instead of a custom class like me and the answers contain only code snippets rather than an explanation of the why there's a problem.
Can anyone help me figure out what's wrong here?
Thanks a bunch!

Answer 1

The errors were caused by binding directly to the fields. Defining those as properties and binding to the properties solved the issue.
Public ReadOnly Property GetID() As String
Get
Return Me.ID
End Get
End Property
Public ReadOnly Property GetName() As String
Get
Return Me.Name
End Get
End Property
Public ReadOnly Property GetState() As String
Get
Return Me.State
End Get
End Property
Public ReadOnly Property GetDisplayName() As String
Get
Return Me.DisplayName
End Get
End Property
And:
Private Sub StartScreen_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'GetAllELData()
ddlMember.DataSource = GetMemberList()
ddlMember.DisplayMember = "GetDisplayName"
ddlMember.ValueMember = "GetID"
End Sub