combobox binding question

[Adam J. Schaff]

I am forgetting something obvious, I think. I have a form with a combobox on
it. I place the code (below) in the form. Instead of populating the dropdown
with 0 and 1, as I expected, it populates it with two rows, each containing
the string "MyProject.Form1+test"

What am I missing (besides sleep)? Do I need to implement some kind of
interface in test?

Public Class test
Public Sub New(ByVal v As Integer)
Me.Value = v
End Sub
Public Value As Integer
End Class

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim x As New ArrayList
x.Add(New test(0))
x.Add(New test(1))
cbo.DataSource = x
End Sub

-AJ

 

[Ken Tucker [MVP]]

Hi,


You can bind to an arraylist and show any property in the class.
Change you class to this.
Public Class test

Dim mVal As Integer

Public Sub New(ByVal v As Integer)

Me.Value = v

End Sub

Public Property Value() As Integer

Get

Return mVal

End Get

Set(ByVal Value As Integer)

mVal = Value

End Set

End Property

End Class



Dont forget to set the display member

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim x As New ArrayList
x.Add(New test(0))
x.Add(New test(1))
cbo.DataSource = x

cbo.displaymember = "Value"
End Sub





Ken
---------------------
I am forgetting something obvious, I think. I have a form with a combobox on
it. I place the code (below) in the form. Instead of populating the dropdown
with 0 and 1, as I expected, it populates it with two rows, each containing
the string "MyProject.Form1+test"

What am I missing (besides sleep)? Do I need to implement some kind of
interface in test?

Public Class test
Public Sub New(ByVal v As Integer)
Me.Value = v
End Sub
Public Value As Integer
End Class

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim x As New ArrayList
x.Add(New test(0))
x.Add(New test(1))
cbo.DataSource = x
End Sub

-AJ

 

[Guest]

For the datasource, you can use any object that implements iList.

If you want to use an ArrayList, just populate it with strings and assign
the ComboBox.datasource to the ArrayList. The ComboBox.SelectedIndex
property will return the zero-based index value of the entry.

You could use a DataTable, or a DataView as the datasource. You can assign
the ComboBox.DisplayMember and ValueMember properties to the corresponding
fields of the DataTable. In that case the SelectedValue property will return
the field value of ValueMember, and DisplayMember provides the list of
visible items.

www.charlesfarriersoftware.com

 

[Adam J. Schaff]

Thanks! I had tried setting the DisplayMember, but I hadn't tried using
true properties instead of public variables. I had no idea there was such a
difference. Ironically, I always use full properties in my classes for
professional work. I was "cheating" here because I was working on a quick,
throwaway application to test a concept.

Anyway, thanks again for the help.