Hi everybody,
I am having a problem getting the selected value of a drop down list that is
populated dynamically inside a datagrid control. When I try to access the
selected item on the datagrid_Update function I get an Object reference not
set to an instance of an object.
I am reakky stuck here and I would appreciate any help from you guys.
Michael
Here is the html markup for the dropdown list inside the datagrid
..
..
..
<asp:TemplateCo lumn HeaderText="Sto re"
HeaderStyle-CssClass="regis terDG-store-header">
<itemtemplate >
<asp:Label ID="lblStore" runat="server"
Text='<%#DataBi nder.Eval(Conta iner.DataItem, "store_name")%> '></asp:Label>
</itemtemplate>
<edititemtempla te><asp:DropDow nList runat="server" ID="ddlStore"
EnableViewState ="true"></asp:DropDownLis t>
</edititemtemplat e>
</asp:TemplateCol umn>
..
..
..
Here is the code snippet inside the datagrid_ItemCr eated Sub that populates
the DropDownList
This works fine and selects the item I want selected.
Dim ddl As DropDownList
ddl = CType(e.Item.Ce lls(1).Controls (1), DropDownList)
Dim register As CRegister
register = New CRegister(regis tersDG.DataKeys (CInt(e.Item.It emIndex)))
Dim oCmd As SqlCommand = Nothing
Dim oDr As SqlDataReader = Nothing
Try
oCn.Open()
oCmd = oCn.CreateComma nd
oCmd.CommandTyp e = CommandType.Tex t
oCmd.CommandTex t = "SELECT * FROM STORES;"
oDr = oCmd.ExecuteRea der
If oDr.HasRows Then
While oDr.Read
ddl.Items.Add(N ew ListItem(oDr.It em("store_name" ),
oDr.Item("store _id").ToString) )
End While
End If
ddl.SelectedVal ue = register.Store. StoreID
Catch SQLEx As SqlException
ExMsg(SQLEx)
Catch ex As Exception
ExMsg(ex)
Finally
If Not IsNothing(regis ter) Then register.Dispos e() : register = Nothing
If Not IsNothing(oDr) Then oDr.Close() : oDr = Nothing
If Not IsNothing(oCmd) Then oCmd.Dispose() : oCmd = Nothing
If Not IsNothing(oCn) Then oCn.Close()
End Try
Here is the code for the datagrid_Update function which trows the exception
Dim register As CRegister
Dim tb As TextBox
Dim cb As CheckBox
Dim ddl As DropDownList
Try
tb = CType(e.Item.Ce lls(0).FindCont rol("txtRegiste rName"), TextBox)
ddl = CType(e.Item.Ce lls(1).FindCont rol("ddlStore") , DropDownList)
cb = CType(e.Item.Ce lls(2).FindCont rol("chkActive" ), CheckBox)
register = New CRegister(regis tersDG.DataKeys (CInt(e.Item.It emIndex)))
register.Regist erName = tb.Text.Trim
register.Active = cb.Checked
'************** *************** *************** *************** ******
'The next line throws Object Reference not set to an instance of an object
exception
'The ddl.Items.Count property returns 0
'The ddl.ID property returns the correct ID of the dropdownlist
'************** *************** *************** *************** ******
register.Store. StoreID = Integer.Parse(d dl.SelectedItem .Value)
If register.Update () Then status.Text = "Register Updated."
Catch ex As Exception
status.Text = ExMsg(ex)
Finally
If Not IsNothing(regis ter) Then register.Dispos e() : register = Nothing
End Try
registersDG.Edi tItemIndex = -1
BindGrid()
