VB Gridview Populating and Sorting - vb.net

Question

I am having a problem getting my GridView's DataSource worked out. I have tried multiple variations in coding, each with their own issues. I have the DataSourceID defined using the GridView Configuration manager. When I attempt to call my stored procedure to populate my GridView, I get no results. So, I tried to define a DataSource in the codebehind and manually bind (and set DataSourceID = '' to avoid error). That populates my GridView very well, but won't allow for sorting.
Here's my question: Does anyone see what I am doing wrong so that neither of these solutions works? I've repurposed code from another project I did, and they are identical (in other project, both DataSourceID and Datasource are used with no error?) Here's my ASP.net Gridview and Proc code:
<asp:GridView ID="gvUserSearch" runat="server" style="z-index: 1; left: 56px; top: 382px; position: absolute; height: 133px; width: 187px" AllowSorting="True" AutoGenerateColumns="False" DataSourceID="UserSearchDataSource" BackColor="White" BorderColor="#999999" BorderStyle="None" BorderWidth="1px" CellPadding="3" GridLines="Vertical">
<AlternatingRowStyle BackColor="Gainsboro" />
<Columns>
<asp:CommandField ShowSelectButton="True" >
<ItemStyle ForeColor="#0066FF" />
</asp:CommandField>
<asp:BoundField DataField="SubscriberID" HeaderText="SubscriberID" SortExpression="SubscriberID" Visible="False" />
<asp:BoundField DataField="Last Name" HeaderText="Last Name" SortExpression="Last Name" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Left" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="First Name" HeaderText="First Name" SortExpression="First Name" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Left" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="EmailAddress" HeaderText="Email Address" SortExpression="EmailAddress" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Left" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="locationid" HeaderText="Unit ID" SortExpression="locationid" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Center" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="unit_name" HeaderText="Unit Name" SortExpression="unit_name" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Left" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="Birthday" HeaderText="Birthday" ReadOnly="True" SortExpression="Birthday" DataFormatString="{0:MMMM/DD/yyyy}" HtmlEncode="False" HtmlEncodeFormatString="False" >
<ItemStyle HorizontalAlign="Center" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="Zip Code" HeaderText="Zip Code" SortExpression="Zip Code" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Center" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="Status" HeaderText="Status" ReadOnly="True" SortExpression="Status" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Left" Wrap="False" />
</asp:BoundField>
<asp:BoundField DataField="DateUnsubscribed" HeaderText="Unsubscribe Date" ReadOnly="True" SortExpression="DateUnsubscribed" DataFormatString="{0:MMMM/DD/yyyy}" HtmlEncode="False" >
<HeaderStyle HorizontalAlign="Center" Wrap="False" />
<ItemStyle HorizontalAlign="Center" Wrap="False" />
</asp:BoundField>
</Columns>
<asp:SqlDataSource ID="UserSearchDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:CafeWorksConnectionString %>" SelectCommand="MarketingPortal_UserSearchProc" SelectCommandType="StoredProcedure">
<SelectParameters>
<asp:ControlParameter ControlID="txtEmail" Name="Email" PropertyName="Text" Type="String" />
<asp:ControlParameter ControlID="txtLastName" Name="LastName" PropertyName="Text" Type="String" />
<asp:ControlParameter ControlID="txtFirstName" Name="FirstName" PropertyName="Text" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
Here is my VB.net codebehind:
Dim CafeWorksConnection As New SqlConnection()
Dim CafeWorksCS As String
Dim CafeWorksDA As SqlDataAdapter
Dim CafeWorksCB As SqlCommandBuilder
Dim CafeWorksDS As New DataSet
Dim CafeWorksSqlC As New SqlCommand
Dim CafeWorksReader As SqlDataReader
Private Sub DBConnect()
'Get the connection string from the web.config file
CafeWorksCS = ConfigurationManager.ConnectionStrings("CafeWorksConnectionString").ConnectionString
'Assign the Connection String to the Connection
CafeWorksConnection.ConnectionString = CafeWorksCS
'Open the database connection
CafeWorksConnection.Open()
End Sub
Private Sub Populate_GridView()
'Make a database connection
DBConnect()
'Define the type of query being executed (Stored Procedure)
CafeWorksSqlC.CommandType = CommandType.StoredProcedure
CafeWorksSqlC.CommandText = "MarketingPortal_UserSearchProc "
'Define the stored procedure parameters
CafeWorksSqlC.Parameters.AddWithValue("#Email", txtEmail.Text)
CafeWorksSqlC.Parameters.AddWithValue("#LastName", txtLastName.Text)
CafeWorksSqlC.Parameters.AddWithValue("#FirstName", txtFirstName.Text)
'Make a connection for the stored procedure to run
CafeWorksSqlC.Connection = CafeWorksConnection
'CafeWorksConnection.Open()
'Executes the stored procedure and stores the result set
CafeWorksReader = CafeWorksSqlC.ExecuteReader()
'You need to bind the data to the GridView
'Got error that DataSourceID and DataSource can't be defined (DataSourceID define in Gridview ASP.net
'code and is not giving me a result set for some reason, so I added the DataSource and DataBind
'gvUserSearch.DataSourceID = ""
gvUserSearch.DataSource = CafeWorksDS
gvUserSearch.DataBind()
'Always close the database connection when you are finished
CafeWorksConnection.Close()
End Sub
Protected Sub btnNameSearch_Click(sender As Object, e As EventArgs) Handles btnNameSearch.Click
'Call the Sub Populate_GridView to display results of search
Populate_GridView()
'Clear out the text boxes - Keeps data from lingering into other searches
txtEmail.Text = ""
txtLastName.Text = ""
txtFirstName.Text = ""
End Sub
I'm still relatively new to this, and my code may not be pretty. I would appreciate any help that anyone could give me. Thank you!

Answer 1

Well your first issue is that you do not have an onsorting attribute of your GridView defined, like this:
onsorting="gvUserSearch_Sorting"
This represents an event handler for whenever a sort operation is needed, such as the user clicking on the header of a column to sort it.
I recommend that you change your DataSource type to DataTable, because the DataTable data structure lends itself to having a view built against it, which you will see later is how we can easily apply the sort direction and the sort expression for the column. Here is a utility function that can return a DataTable to be used by your DataSource property:
Private Function GetGridViewDataSource() As DataTable
Dim dtGrid As New DataTable()
Dim con As New SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
' Change this to either execute the SQL you want or change the command object to execute a stored procedure
Dim strSelect As String = "SELECT FirstName,LastName,Location FROM Details"
Dim cmd As New SqlCommand(strSelect, con)
Dim dAdapter As New SqlDataAdapter(cmd)
dAdapter.Fill(dtGrid)
Return dtGrid
End Function
Note: You would need to change your DataSource assignment to call this function, like this: gvUserSearch.DataSource = GetGridViewDataSource()
Now that we have the source as a DataTable, we can start to manage the sorting, specifically keeping track of sort direction (ascending or descending) via a class property, like this:
Public Property dir() As SortDirection
Get
If ViewState("dirState") Is Nothing Then
ViewState("dirState") = SortDirection.Ascending
End If
Return DirectCast(ViewState("dirState"), SortDirection)
End Get
Set
ViewState("dirState") = value
End Set
End Property
Now we are finally ready to implement the actual sorting handler, like this:
Protected Sub gvDetails_Sorting(sender As Object, e As GridViewSortEventArgs)
Dim sortingDirection As String = String.Empty
If dir = SortDirection.Ascending Then
dir = SortDirection.Descending
sortingDirection = "Desc"
Else
dir = SortDirection.Ascending
sortingDirection = "Asc"
End If
Dim sortedView As New DataView(GetGridViewDataSource())
sortedView.Sort = Convert.ToString(e.SortExpression) & " " & sortingDirection
gvDetails.DataSource = sortedView
gvDetails.DataBind()
End Sub
Note: What this method does is to ask the ViewState what the sorting direction is and then creates a DataView from the DataTable and applies the sorting expression, defined in the grid view column, and the sorting direction to rebind the data source to grid.