Question

I have 5 dropdown lists and am trying to make it so if I choose a certain value on a certain dropdown list, it won’t show that specific item on the following dropdown lists.

I am doing this through a specific SQL query on each dropdown list’s data source, the code is in the following pastebin link because the StackOverflow textbox is buggy for me for some reason:
http://pastebin.com/gDm8MPrL

I’m not exactly sure why, but it isn’t displaying anything from the database. When I test a normal “SELECT *” query it works, so it isn’t a connection problem.

Could anyone give me a hand?

Thanks!

PASTED CODE FROM PASTE BIN

<asp:DropDownList ID="ddlHero1" runat="server" DataSourceID="ddlDataSource0"                        DataTextField="ChampName" DataValueField="ChamadpName" AutoPostBack="True">
</asp:DropDownList>
<asp:SqlDataSource ID="ddlDataSource0" runat="server" ConnectionString="<%$ ConnectionStrings:mobamanagerConnectionString%>" SelectCommand="SELECT [ChampName] FROM [Champions] WHERE Champname NOT IN (
SELECT [ChampName] FROM [Champions] WHERE Champname=@ddlHero2 
UNION 
SELECT [ChampName] FROM [Champions] WHERE Champname=@ddlHero3
UNION
SELECT [ChampName] FROM [Champions] WHERE Champname=@ddlHero4
UNION
SELECT [ChampName] FROM [Champions] WHERE Champname=@ddlHero5)">
   <SelectParameters>
        <asp:ControlParameter ControlID="ddlHero2" Name="ddlHero2" 
                                                PropertyName="SelectedValue" />
        <asp:ControlParameter ControlID="ddlHero3" Name="ddlHero3" 
                                                PropertyName="SelectedValue" />
        <asp:ControlParameter ControlID="ddlHero4" Name="ddlHero4" 
                                                PropertyName="SelectedValue" />
        <asp:ControlParameter ControlID="ddlHero5" Name="ddlHero5" 
                                                PropertyName="SelectedValue" />
   </SelectParameters>
</asp:SqlDataSource>

This process is repeated another 4 times with different queries for each DDL, but the procedure is identical.

EDIT: Thanks for pasting the code in, mod!

Answer 1

For your case you can do it with or without Ajax, but essentially make all the lists
AutoPostback=”true”
and enabled=”false” except the first and then do something like the following:
this sample code in VB

   Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Not Page.IsPostBack Then
        'here load the first only
        'make the 2d enabled
    Else
        If ViewState("ddlHero1").ToString <> "" Then
            'get the value of the 1st from the viewstate
            'ddlHero1.selectedindex=cint(ViewState("ddlHero1").ToString)
            'make the 2nd enabled
            'bind the second
        End If
        If ViewState("ddlHero2").ToString <> "" Then
            'get the value from viewstate
            'ddlHero2.selectedindex=cint(ViewState("ddlHero2").ToString)
            'make the 3nd enabled
            'bind the 3rd
        End If
        If ViewState("ddlHero3").ToString <> "" Then
            'like the 2nd..etc
        End If
    End If
End Sub

on the SelectedIndexChanged event for each list save the selected value in the viewstate

Protected Sub ddlHero1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlHero1.SelectedIndexChanged

    ViewState("ddlHero1") = ddlHero1.SelectedIndex.ToString
    'and the same for the other lists

End Sub