Changing Position property of Binding Source does not take effect

Question

I have a BindingSource, let's call it myBindingSource, whose DataSource is a List(Of myClass).  There are several lines in the existing code that set the Position property of the BindingSource object and the set is effective, e.g. if
the Position value is 0 and I do this...
  myBindingSource.Position = 1
...I can check the value of myBindingSource.Position and it is 1.  However other times (and it may only be when the current value is -1) when I do such a set, nothing happens.  The Position value remains at the previous value, e.g. after the above
line, SpecimenNavSource.Position is still -1.  I have verified that at that point, the SpecimenNavSource.Count is greater than the value I'm setting, so it's not that it can't find something in that position.
Any ideas would be greatly appreciated.
Thanks.
mamacasc

Answer 1

Hello,
Here is a small demonstration project which has a BindingNavigator placed on the form. Pressing Button1 at any position will move bsData to position 0. With that can you show if different from the below what you are doing?
Public Class Form1
Private bsData As New BindingSource
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim People As New List(Of Person) From
New Person With
{.FirstName = "Karen", .LastName = "Payne"},
New Person With
{.FirstName = "Jim", .LastName = "Smith"},
New Person With
{.FirstName = "Mary", .LastName = "Olson"}
bsData.DataSource = People
AddHandler bsData.PositionChanged,
Sub(s As Object, ea As EventArgs)
Me.Text = bsData.Position.ToString
End Sub
BindingNavigator1.BindingSource = bsData
DataGridView1.AllowUserToAddRows = False
DataGridView1.DataSource = bsData
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
bsData.Position = -1 ' postion is set to 0
End Sub
End Class
Public Class Person
Public Property FirstName As String
Public Property LastName As String
Public Sub New()
End Sub
End Class
Lastly, I peeked at BindingSource.cs, source code for BindingSource and there is nothing there to allow moving below position 0.
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