Refresh/Requery combobox on form after record saved on separate form - vb.net

Question

I have spent all morning googling and looking through this site and just haven't found anything that seems to work. I have a combobox on form1 that gets its display values from a datasource tblCardTypeDD. Its Display Member is sCardType and its value member is iCardTypeID. Its selected member is fkCardTypeID from tblInventory.
When I click a button form2 pops up with a simple datagridview that allows me to add more card types to be used in the drop down. Currently I have been trying to add code to the save button click method but I just can't find a combination that actually updates the combobox.
I have been trying the following:
frmInventory.SEquipTypeComboBox.DataSource = Nothing
frmInventory.SEquipTypeComboBox.DataSource = Me.EngDBbeDataSet.tblCardTypeDD
but the drop down becomes blank after execution of the above.
Any help would be appreciated.

Answer 1

You should check this page, maybe it'll help you:
http://msdn.microsoft.com/en-us/library/w67sdsex.aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1
In case it didn't:
if you put your breakpoint where you "reset" The combobox Datasource binding, Check if the datasource contains the new values you want to see in your combobox. it might sound stupid but its a mistake that often happens, if this is the case you know that the problem isn't with the binding
Also after making the datasource nothing and adding the datasource again in the way you did you should tell which column will be the displaymember again like so:
ComboBox1.DisplayMember = "Column1"
Though if you look at the site I told you about you should look at the note that tells you how to suspend and resume binding instead of dropping the datasource and adding it again like that.
Though if you're using a datatable the values should automatically change, and there should be no reason to drop and rebind the combobox.
--
To prove that you don't need to rebind i've very quickly made a very dirty piece of code to prove it.
form1 has a combobox that's bound to a datatable, and it also has a button to call a second form named form2.
form2 has a button that adds 2 rows to the Datatable and then goes back to the first screen.
Code Form 1:
Public Class Form1
Private dataSet As New DataSet("DataSet1")
Private dataTable As DataTable = dataSet.Tables.Add("DataTable1")
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
dataTable.Columns.Add("Column1")
Dim row1 As DataRow = dataTable.NewRow()
row1("Column1") = "Data1"
dataTable.Rows.Add(row1)
Dim row2 As DataRow = dataTable.NewRow()
row2("Column1") = "Data2"
dataTable.Rows.Add(row2)
ComboBox1.DataSource = dataTable
ComboBox1.DisplayMember = "Column1"
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim form2 As New Form2(dataTable)
form2.Show()
End Sub
End Class
Code Form2:
Public Class Form2
Private _dataTable As DataTable
Public Sub New(ByVal dataTable As DataTable)
InitializeComponent()
_dataTable = dataTable
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim row3 As DataRow = _dataTable.NewRow()
row3("Column1") = "Data3"
_dataTable.Rows.Add(row3)
Dim row4 As DataRow = _dataTable.NewRow()
row4("Column1") = "Data4"
_dataTable.Rows.Add(row4)
Me.Close()
End Sub
End Class