I am writing an ASP.Net web application. I have listview, it's datasource is a LinqDataSource. In my database, I have a staff table and I am trying filter for records by their team using a dropdownlist. This works fine, until I select "All" in the dropdownlist. It returns all staff except for the ones where the teamID is null. How can I return the records where teamID is null?
This is my code:
<asp:ListView ID="ListView1" runat="server" DataSourceID="ldsStaff" DataKeyNames="staffID">
<LayoutTemplate>
<table>
<tr>
<th>Name</th>
<th>Team</th>
</tr>
<tr>
<td> </td>
<td><asp:DropDownList ID="ddlTeamFilter" runat="server" DataSourceID="ldsTeams" DataTextField="Team" DataValueField="TeamID" AppendDataBoundItems="true" AutoPostBack="true">
<asp:ListItem Text="[All]" Value=""></asp:ListItem>
</asp:DropDownList>
</td>
</tr>
<tr ID="itemPlaceHolder" runat="server"></tr>
</table>
</LayoutTemplate>
....
</asp:Listview>
<asp:LinqDataSource ID="ldsStaff" runat="server"
ContextTypeName="ProjectDatabase.ProjectDatabaseUsersDataContext" OrderBy="name"
TableName="Staffs" EnableUpdate="True" Where="inService == @inService && TeamID == @TeamID">
<WhereParameters>
<asp:Parameter DefaultValue="true" Name="inService" Type="Boolean" />
<asp:ControlParameter ControlID="ctl00$ContentPlaceHolder1$ListView1$ddlTeamFilter" Name="TeamID" Type="Int32" PropertyName="SelectedValue"/>
</WhereParameters>
</asp:LinqDataSource>
In my code behind I handle the LinqDataSource selecting event:
Private Sub ldsStaff_Selecting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.LinqDataSourceSelectEventArgs) Handles ldsStaff.Selecting
Dim ddl As DropDownList = CType(ListView1.FindControlRecursive("ddlTeamFilter"), DropDownList)
If ddl.SelectedValue = "" Then
e.WhereParameters.Remove("TeamID")
End If
I thought that if I removed the whereparameter when the dropdownlist is "All" it would force it to return all the records, but it doesn't work.
Please help!
Thanks, Emma