Populating dropboxes with SQL data - asp.net

Question

I have a few more questions regarding my latest project. Ive felt like I have made some pretty good strides over the last couple days, but I am still struggling on a few of the core concepts of the SQL libraries, namely reading from specific columns and deleting entire rows.
Over the last week I was able to build a webform, save excel files to the server, open those files and export data into specific SQL tables, and bind the data to specific data grids depending on what the user chooses through a dropdown.
What I would like to accomplish is: Dynamic population of another dropdown depending on what the user chooses from the first drop down. More specifically, I have 4 tables, in the first column of each table I have serial numbers, if the user chooses Table2 in the first drop down, I would like the second dropdown to display all the serial numbers from column1 of Table2. Then if the user choose a specific serial number from the second drown down it populates a datagrid with columns 1-5 of that related row.
The second part is to create a delete button that the user can push after the information is displayed in the datagrid, that deletes the entire row of the serial number entry from that table.
This is what I have managed to Frankenstein together from other examples:
Protected Sub DropDownList1_SelectedIndexChanged(sender As Object, e As System.EventArgs)
DropDownList2.Enabled = True 'its remains disabled until the user selects something from the first box
Using con As New SqlClient.SqlConnection
con.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=" & AppPath & "App_Data\DeviceDatabase.MDF;Integrated Security=True;User Instance=True;"
Using cmd As New SqlClient.SqlCommand
cmd.Connection = con
End Using
Dim cmdSQL As New SqlCommand()
cmdSQL.CommandType = Data.CommandType.Text
cmdSQL.CommandText = "SELECT Fieldname1 FROM " & """" & DropDownList1.SelectedItem.ToString & """" 'Im pretty sure this isnt right, and the reason I use """"" is because some of the items in the dropdown have spaced words.
Dim adptSQL As New SqlClient.SqlDataAdapter(cmdSQL)
Dim myDataSet As New DataSet()
adptSQL.Fill(myDataSet)
With myDataSet.Tables(DropDownList1.SelectedIndex) 'I think this is right
For rowNumber As Integer = 0 To .Rows.Count - 1
With .Rows(rowNumber)
DropDownList2.Items.Add(col1.rowNumber) 'This is obviously not working
End With
Next
End With
End Using
End Sub
Then, Im not quite sure how to populate the data table with the row that was selected, though currently I am able to do the entire table with using:
Private Sub GenTables(ByVal DropList As Object)
If DropList.SelectedIndex = 0 Then
GridView1.DataSourceID = Nothing
ElseIf DropList.SelectedIndex = 1 Then
GridView1.DataSourceID = "SqlDataSource1"
ElseIf DropList.SelectedIndex = 2 Then
GridView1.DataSourceID = "SqlDataSource2"
ElseIf DropList.SelectedIndex = 3 Then
GridView1.DataSourceID = "SqlDataSource3"
ElseIf DropList.SelectedIndex = 4 Then
GridView1.DataSourceID = "SqlDataSource4"
End If
GridView1.DataBind()
End Sub
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:DeviceDatabaseConnectionString1 %>"
ProviderName="<%$ ConnectionStrings:DeviceDatabaseConnectionString1.ProviderName %>"
SelectCommand="SELECT [Device:] AS column1, [SWversion:] AS column2, [Date:] AS column3, [Tester:] AS column4, [Wifi Preferred InCov:] AS column5 FROM [Galaxy Nexus]">
</asp:SqlDataSource>
'there are 3 more of these.
But I have these tables "hard coded" into the application, I can't obviously do this with every single table row. So how do I populate a datagrid without setting a SQLDataSource ahead of time in asp?
And lastly deleting the row that relates to the information displayed in the datagrid on the click of a button. If if can get a little help with the first part, Im sure I can figure out the second part.
So pretty much what I am asking is: how to populate a drop down with all the items from Coloumn1? and how to populate a datagrid from a specific row?
Any and all help is always greatly appreciated. Thanks Guys
Zach
EDIT
hmm I think I was making this a ton harder then it had to be, right now I am working with this:
Protected Sub BindDrop_Click(sender As Object, e As System.EventArgs)
DropDownList2.DataSourceID = "SqlDataSource5"
DropDownList2.DataBind()
End Sub
<asp:SqlDataSource ID="SqlDataSource5" runat="server"
ConnectionString="<%$ ConnectionStrings:DeviceDatabaseConnectionString1 %>"
ProviderName="<%$ ConnectionStrings:DeviceDatabaseConnectionString1.ProviderName %>"
SelectCommand="SELECT [Device:] AS column1 FROM [Galaxy Nexus]">
Its not quite right but its closer and in 1/10th the lines

Answer 1

alright guys i figured it out, I needed to use the ExecuteReader function (which crazily enough I couldnt find one article in auto population that uses this method). Hopefully in writing/answering this I make someone's life much easier.
Protected Sub DropDownList2_SelectedIndexChanged(sender As Object, e As System.EventArgs)
DropDownList3.Enabled = True
DropDownList3.Items.Clear()
Dim newsqlcommand As String = "Select [SWversion:] FROM " & """" & DropDownList2.SelectedItem.ToString & """"
Using con As New System.Data.SqlClient.SqlConnection(connexstring)
con.Open()
Using cmd As New SqlCommand(newsqlcommand, con)
Dim myReader As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
While myReader.Read()
DropDownList3.Items.Add(myReader.GetString(0))
End While
myReader.Close()
cmd.Dispose()
End Using
con.Close()
con.Dispose()
End Using
Dbind()
End Sub
This successfully reads all the items in the column "SWVersion" and adds them to the dropdown in dropdown3. Enjoy!