Populate a combobox with in vb.net based on a selection of another combo box from databse
<p>I have 2 combo boxes and a couple of labels, the thing is I want to pull up data from one of my database columns which is the drug_group and after that I want whenever I select a drug group from the first combo box the corresponding drug name from the database should be populated on the second combobox. And after that the labels should pull the drugs information. My issue here is that the first combobox does get populated but it kinda repeats some of the data. and then when I select any of the item from the first combo box thesame items get displayed. Below is my code and screenshot is attached of my progress so far. I just want to know how to go about it thanks.</p>

<pre class="lang-vb prettyprint-override"><code>Private Sub storeform_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'PhermacyDataSet.tblsolddrugs' table. You can move, or remove it, as needed.
    Me.TblsolddrugsTableAdapter.Fill(Me.PhermacyDataSet.tblsolddrugs)
    'TODO: This line of code loads data into the 'PhermacyDataSet1.tbldrug' table. You can move, or remove it, as needed.

    'Drug Group Combo box
    Dim connString As String = "Data Source=.\SQLEXPRESS;Database=phermacy; Integrated Security = true"
    Dim conn As New SqlConnection(connString)
    Dim strSQL As String = "SELECT * FROM tbldrug"
    Dim da As New SqlDataAdapter(strSQL, conn)
    Dim ds As New DataSet
    da.Fill(ds, "tbldrug")

    With cmbdruggp
        .DataSource = ds.Tables("tbldrug")
        .DisplayMember = "Drug_group"
        .ValueMember = "Drug_ID"
        .SelectedIndex = 0
    End With

    'Drug Name combo
    Dim strSQL1 As String = "SELECT Drug_Name FROM tbldrug WHERE Drug_group =" &amp; Me.cmbdruggp.SelectedValue
    Dim da1 As New SqlDataAdapter(strSQL1, conn)
    Dim ds1 As New DataSet
    da.Fill(ds1, "tbldrug")

    With cmbdrugname
        .DataSource = ds1.Tables("tbldrug")
        .DisplayMember = "Drug_Name"
        .ValueMember = "Drug_group"
        .SelectedIndex = 0
    End With


End Sub
</code></pre>

<p><a href="http://i.stack.imgur.com/jZL3z.png" rel="nofollow">My form layout</a></p>