Linking of database tables by pID - asp.net

Question

I have problem linking 2 datatables using a pID. It isn't an automated number. The thing is, I have to save the pID number into the database when I select an option in a drop down list. But the options shown are course names (Text).
After selecting from the drop down list, input text into a textbox and then click on a button to save both the pID number and description into the database. In 1 database table, it has the course name and pID number. The 2nd database table has the pID number and description(Save info into here).
I'm only able the save the selectedindex, which isn't the pID number.
.aspx.vb Code
Dim OdbcCon As New System.Data.Odbc.OdbcConnection
Dim cmd As New OdbcCommand
OdbcCon.Open()
cmd.Connection = OdbcCon
cmd.CommandText = " insert into StdBookInfo(pID,Description) values ('" & DropDownListStudent.SelectedIndex & "','" & TextBox1.Text & "') "
cmd.ExecuteNonQuery()
Code for drop down list:
sqlcmd3 = "select Course_code + ' - ' + package from StudentPackage order by pID asc "
sqlcmd4 = "select pID from StudentPackage order by Course_code,package asc "
cmd3.Connection = OdbcCon
cmd3.CommandText = sqlcmd3
DropDownListStudent.Items.Add("")
reader3 = cmd3.ExecuteReader
While reader3.Read
DropDownListStudent.Items.Add(reader3.Item(0).ToString)
End While
DropDownListStudent.SelectedIndex = -1
reader3.Close()
cmd3.Dispose()
cmd4.Connection = OdbcCon
cmd4.CommandText = sqlcmd4
reader4 = cmd4.ExecuteReader
I = 0
While reader4.Read
pID(I) = reader4.Item(0)
I = I + 1
End While
reader4.Close()
cmd4.Dispose()
OdbcCon.Close()

Answer 1

You need to set the Text and Value properties of each item of DropDownList, then use SelectedValue instead SelectedIndex.
<asp:DropDownList id="DropDownListStudent" Runat="Server">
<asp:ListItem Text="Item 1" Value="1"/>
<asp:ListItem Text="Item 2" Value="2"/>
<asp:ListItem Text="Item 3" Value="3"/>
<asp:ListItem Text="Item 4" Value="4"/>
<asp:ListItem Text="Item 5" Value="5"/>
</asp:DropDownList>