Lookup value of a datalist for a gridview - asp.net

Question

4h
Hello everyone.
I have been pulling my hair out on this one. I can't see what I am doing wrong. Can someone please help.
I have a datalist which I pull value from a table. Then I want to pull values for a gridview that matches the value of the datalist. Appreciate your help!!!
My Datalist:
<asp:DataList ID="ModelCodeLabel" runat="server" DataSourceID="ModelCode"
CssClass="code" Width="250px" DataKeyField="Code">
<ItemTemplate>
<asp:Label ID="CodeLabel" runat="server" Text='<%# Eval("Code") %>' />
<br />
<br />
</ItemTemplate>
</asp:DataList>
<asp:SqlDataSource ID="ModelCode" runat="server"
ConnectionString="<%$ ConnectionStrings:TechCenterConnectionString %>"
SelectCommand="SELECT DISTINCT [Code] FROM [tblSidingModels] WHERE (([Series] = #Series) AND ([Model] = #Model))">
<SelectParameters>
<asp:ControlParameter ControlID="ddSeries" Name="Series"
PropertyName="SelectedValue" Type="String" />
<asp:ControlParameter ControlID="ddModel" Name="Model"
PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
My Gridview:
<asp:GridView ID="GV_Performance" runat="server" Width="100%"
AutoGenerateColumns="False" BackColor="LightGoldenrodYellow" BorderColor="Tan"
BorderWidth="1px" CellPadding="2" DataSourceID="ModelPerformance"
ForeColor="Black" GridLines="None">
<AlternatingRowStyle BackColor="PaleGoldenrod" />
<Columns>
<asp:BoundField DataField="Code" HeaderText="Code" SortExpression="Code" />
<asp:BoundField DataField="Description" HeaderText="Description"
SortExpression="Description" />
<asp:BoundField DataField="ReportNo" HeaderText="ReportNo"
SortExpression="ReportNo" />
</Columns>
<FooterStyle BackColor="Tan" />
<HeaderStyle BackColor="Tan" Font-Bold="True" />
<PagerStyle BackColor="PaleGoldenrod" ForeColor="DarkSlateBlue"
HorizontalAlign="Center" />
<SelectedRowStyle BackColor="DarkSlateBlue" ForeColor="GhostWhite" />
<SortedAscendingCellStyle BackColor="#FAFAE7" />
<SortedAscendingHeaderStyle BackColor="#DAC09E" />
<SortedDescendingCellStyle BackColor="#E1DB9C" />
<SortedDescendingHeaderStyle BackColor="#C2A47B" />
</asp:GridView>
<asp:SqlDataSource ID="ModelPerformance" runat="server"
ConnectionString="<%$ ConnectionStrings:TechCenterConnectionString %>"
SelectCommand="SELECT DISTINCT [Code], [Description], [ReportNo] FROM [tblSidingTestReport] WHERE ([Code] = #Code)">
<SelectParameters>
<asp:ControlParameter ControlID="ModelCodeLabel" Name="Code"
PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>

Answer 1

Ok, so the idea is you have a datalist. User selects/clicks on that given row, and then you want to display the related data from that choice into a grid view.
I don't have your data, but let's take a data list of hotels.
When user selects a hotel, then we will display people booked in that hotel into the gv.
So, in effect we want a "cascade" from the data list to the gv.
Ok, so our simple markup for the data list is this:
<div style="float: left">
<h4>Hotels</h4>
<asp:DataList ID="DataList1" runat="server" DataKeyField="ID">
<ItemTemplate>
<div style="float: left; width: 400px">
<h4><%# Eval("HotelName") %></h4>
<asp:Label ID="DescriptionLabel" runat="server" Text='<%# Eval("Description") %>' />
</div>
<div style="float: left; margin-top: 5%">
<asp:Button ID="cmdSee" runat="server" Text="View Bookings" CssClass="btn"
OnClick="cmdSee_Click" />
</div>
<div style="border-bottom: 2px solid black"></div>
</ItemTemplate>
</asp:DataList>
</div>
And after data list, then the grid view like this:
<div style="float: left; margin-left: 25px">
<h4>Booked in Hotel</h4>
<asp:GridView ID="GridView1" runat="server" CssClass="table table-hover"
AutoGenerateColumns="False" DataKeyNames="ID"
Width="40%">
<Columns>
<asp:BoundField DataField="Firstname" HeaderText="Firstname" />
<asp:BoundField DataField="LastName" HeaderText="LastName" />
<asp:BoundField DataField="City" HeaderText="City" />
</Columns>
</asp:GridView>
Ok, so the next tip/concept?
While I often still use the wizards to create the datalist or gridview?
I then blow out (delete + remove the sql data source in the current markup).
The reason for "removing" the on page SQL data source is lack of "control" over what occurs.
So, when starting out, using a wizard-based data source dropped right into that page markup can be handy, but once you want to do "more fancy" or "more complex" things, then over time, you find as a developer, you take over this automated process.
So, remove the sql data sources from your page. (and from the datalist, and gridview, ALSO remove the sql data source you specified).
We will in place of above, simple write a "small" amount of code to do the same data loading, but MORE important this ALSO gives one more control over the data loading process, and hence with more control, then the solution becomes rather simple.
Ok, so our code to load up the data list can look like this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadData
End If
End Sub
Sub LoadData()
DataList1.DataSource = Myrst("SELECT * FROM tblHotelsA ORDER BY HotelName")
DataList1.DataSource = Myrst(strSQL)
DataList1.DataBind()
End Sub
So, we now see/get this:
Ok, so now all we have to do is wire up the button click code.
that code is this:
Protected Sub cmdSee_Click(sender As Object, e As EventArgs)
Dim btn As Button = sender
Dim gRow As DataListItem = btn.NamingContainer
Dim intPK As Integer = DataList1.DataKeys(gRow.ItemIndex) ' get row click PK id
Dim strSQL = "SELECT * FROM People WHERE Hotel_ID = " & intPK
GridView1.DataSource = Myrst(strSQL)
GridView1.DataBind()
End Sub
And, to save keyboards wearing out? I have this helper routine to get my data (it returns a data table).
Public Function Myrst(strSQL As String) As DataTable
Dim rstData As New DataTable
Using mycon As New SqlConnection(My.Settings.TEST4)
Using cmdSQL As New SqlCommand(strSQL, mycon)
mycon.Open()
rstData.Load(cmdSQL.ExecuteReader)
End Using
End Using
Return rstData
End Function
So, when I click on a button, then I see/get this: