problem about combination gridview-dropdownlist (and selectedvalue)

[Ben]

Hi,

It's about a database containing (for simplifying) three fields: 'placenr'
(primary key), 'place' and 'color'. The records are updatable (Edit/Update
button) in a gridview. For updating the field 'color', the selectedvalue of
a dropdownlist must be used, containing all possible colors (red, blue ...),
so the field 'color' is ReadOnly in the gridview.
Everything works, but i still have 2 problems:

1)the new color in the field is always the first element of the dropdownlist
(here the value "choose"), whatever i choose in it.
2)If only the field 'place' must be updated but not the field 'color'(no
click in the dropdownlist), the original color in the field 'color' is
nevertheless always replaced by the first value (again value "choose") in
the dropdownlist.

Any hints or idea for solving that?

Thanks
Ben

Here part of the code-behind file:
----------------------------------
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArg s)
Handles Me.Load
...
sConnectionStri ng = "Provider = Microsoft.Jet.O LEDB.4.0; Data Source
= c:\mydb.mdb"
sql = "SELECT [color] FROM [color];"
d = New OleDbDataAdapte r(sql, sConnectionStri ng)
ds = New DataSet()
x = d.Fill(ds)

If Page.IsPostBack Then
dindex = DropDownList1.S electedIndex
dvalue = DropDownList1.S electedValue
DropDownList1.I tems.Clear()
End If

z = New ListItem("choos e a color", "choose")
DropDownList1.I tems.Add(z)

For i = 0 To x - 1
kl = ds.Tables(0).Ro ws(i).Item(0)
z = New ListItem(kl, kl)
DropDownList1.I tems.Add(z)
Next
End Sub

Protected Sub DropDownList1_S electedIndexCha nged(ByVal sender As Object,
ByVal e As System.EventArg s) Handles DropDownList1.S electedIndexCha nged
If dindex 0 Then '0 = "choose"
DropDownList1.S electedValue = dvalue
End If
End Sub
End Class

Here part of the aspx file:
---------------------------
<asp:SqlDataSou rce ID="SqlDataSour ce1" runat="server"
ConflictDetecti on="CompareAllV alues"
ConnectionStrin g="Provider=Mic rosoft.Jet.OLED B.4.0;Data Source=C:\mydb. mdb"
OldValuesParame terFormatString ="original_{ 0}"
ProviderName="S ystem.Data.OleD b"
SelectCommand=" SELECT * FROM [place]"
UpdateCommand=" UPDATE [place] SET [placename] = ?, [color] = @color WHERE
[placenr] = ?">
<UpdateParamete rs>
<asp:Paramete r Name="placename " Type="String" />
<asp:ControlPar ameter ControlID="drop downlist1"
Name="color" PropertyName="S electedValue" Type="String" />

<asp:Paramete r Name="original_ placenr" Type="Int32" />
<asp:Paramete r Name="original_ placename" Type="String" />
<asp:Paramete r Name="original_ color" Type="String" />
</UpdateParameter s>
</asp:SqlDataSour ce>

<asp:GridView ID="GridView1" runat="server" AllowPaging="Tr ue"
AutoGenerateCol umns="False" CellPadding="4"
DataKeyNames="p lacenr" DataSourceID="S qlDataSource1">
<Columns>
<asp:CommandFie ld ShowEditButton= "True"/>
<asp:BoundFie ld DataField="plac enr" ReadOnly="True"/>
<asp:BoundFie ld DataField="plac ename" />
<asp:BoundFie ld DataField="colo r" ReadOnly="True" />
</Columns>
</asp:GridView>
<asp:DropDownLi st ID="DropDownLis t1"
runat="server" AutoPostBack="T rue">
</asp:DropDownLis t>