Data Binding Gridview to a Second Gridview

Question

Good Morning,

I am developing a quote request functionality as part of a website. The idea here is for the user to search for parts, update the textbox field in the first gridview for items they wish to select, click Add to Quote embedded in the first gridview, and send those rows to a second gridview wherein they can edit quantities or remove rows completely. The second gridview will then need to be encapsulated in a Wizard Control or something similar (on different page?) where in contact information is supplied and all data saved to the quote table in the database.

The issue I'm having is that the data is not being passed from the first gridview to the second. I'm new to data access controls, and have read that I needed to use a data table to store the results so they can be sent to the second gridview. Here's a snippet of my ASPX page:

<div id="searchbox">  
<fieldset id="Fieldset1">  
<asp:Label runat="server" ID="lblPartName" Text="Search by Part Name"></asp:Label>  
<asp:TextBox runat="server" ID="txtSearch"></asp:TextBox>  
<asp:Label runat="server" ID="lblNSN" Text="Search by NSN"></asp:Label>  
<asp:TextBox runat="server" ID="txtNSN"> </asp:TextBox>  
<asp:Button runat="server" ID="btnSubmit" Text="Search" />  
</fieldset>  
<asp:Label runat="server" ID="lblItems" Text="Selected Parts"></asp:Label>  
<asp:GridView runat="server" ID="gvItems" AutoGenerateColumns="False">  
</asp:GridView>  

</div>  
<div id="results">  
<asp:GridView ID="MySearch" runat="server"    
        AllowSorting="True" AutoGenerateColumns="False"    
        AllowPaging="True" DataSourceID="DSParts" ShowFooter="True"    
        DataKeyNames="PARTNUMBER,NSN,PARTNAME">  
<Columns>  
<asp:BoundField DataField="PARTNUMBER" HeaderText="PARTNUMBER"    
                SortExpression="PARTNUMBER" />  
<asp:BoundField DataField="NSN" HeaderText="NSN" SortExpression="NSN" />  
<asp:BoundField DataField="PARTNAME" HeaderText="PARTNAME"    
                SortExpression="PARTNAME" />  
<asp:TemplateField HeaderText="Qty">  
<ItemTemplate >  
<asp:TextBox runat="server" ID="txtQty"></asp:TextBox></ItemTemplate>  
<FooterTemplate>  
<asp:Button runat="server" Text="Add to Quote" ID="btnAddQuote" />  
</FooterTemplate>  
</asp:TemplateField>  
</Columns>       
</asp:GridView>           
<asp:SqlDataSource runat="server" ID="DSParts"    
        ConnectionString="<%$ ConnectionStrings:Diel_inventoryConnectionString %>"    
        SelectCommand="PartSproc" SelectCommandType="StoredProcedure"    
        CancelSelectOnNullParameter="False">  
<SelectParameters>  
<asp:ControlParameter ControlID="txtNSN" Name="NSN" PropertyName="Text"    
                   Type="String" />  
<asp:ControlParameter ControlID="txtSearch" Name="PartName" PropertyName="Text"    
                   Type="String" />  
</SelectParameters>  
</asp:SqlDataSource>  

</div>     

Here's the contents of my codebehind file:

Imports MyApp.WebControls.SearchGridView   
Imports System.Data   
Imports System.Data.SqlClient   
Imports System.Web.Configuration   

Partial Class PartSearch   
Inherits System.Web.UI.Page   

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load   
If Not (IsPostBack) Then  

'Define DataTable Columns as incoming gridview fields   
Dim dtSelParts As DataTable = New DataTable   
Dim dr As DataRow = dtSelParts.NewRow()   
Dim gvr As GridViewRow   

dtSelParts.Columns.Add("PartNumber")   
dtSelParts.Columns.Add("NSN")   
dtSelParts.Columns.Add("PartName")   
dtSelParts.Columns.Add("Qty")   

'Select those gridview rows that have txtQty <> 0   
For Each row As GridViewRow In MySearch.Rows   
Dim textboxText As String = _   
CType(row.FindControl("txtQty"), TextBox).Text   
If textboxText <> "0" Then  
'Create the row   
dr = dtSelParts.NewRow()   
'Fill the row with data   
dr("PartNumber") = MySearch.DataKeys(row.RowIndex)("PartNumber")   
dr("NSN") = MySearch.DataKeys(row.RowIndex)("NSN")   
dr("PartName") = MySearch.DataKeys(row.RowIndex)("PartName")   
dr("Qty") = MySearch.DataKeys(row.RowIndex)("Qty")   
'Add the row to the table   
dtSelParts.Rows.Add(dr)   
End If  
Next  
'Need to send items to Gridview control gvItems   

For Each gvr In gvItems.Rows   
dr = dtSelParts.NewRow()   
dr("PartNumber") = gvr.Cells(0).Text   
dr("NSN") = gvr.Cells(1).Text   
dr("PartName") = gvr.Cells(2).Text   
dr("Qty") = gvr.Cells(3).Text   
dtSelParts.Rows.Add(dr)   
Next  
End If  
End Sub  

Protected Sub btnSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSubmit.Click   
MySearch.DataBind()   
End Sub  

Questions: 1. Please help me understand why the second gridview gvItems is not receiving the selected rows from gridview MySearch. What needs to be corrected/added to make this work? 2. Is there another "best practice" for this type of process? That is, am I making correct use of a second gridview to store selected items, or is there another control that works better/more efficiently for this task? 3. Given that the customer needs to provide their contact information etc. as part of the quote process, should gvItems be encapsulated in a Wizard Control as step 1? Should it stay on the same page as gridview MySearch or should it be on a page of it's own?
4. Please send links/samples of similar quote request processes that you have done and are willing to share. 5. The code has been placed in Page_Load, should it be moved to the click event of btnAddQuote instead?
6. If I need to move the code to the click event of btnAddQuote, should I still wrap it in If Not (isPostBock) then block?

Thanks much, Sid