Bind LinqDataSource to UserId using Profile Data.xml

    <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
        ContextTypeName="Company.Data.CompanyDataContext" OrderBy="FirstName" 
        Select="new (Id, LastName, FirstName)" TableName="Persons" 
        Where="CreatedByUserId == @CreatedByUserId">
        <WhereParameters>
            <asp:ProfileParameter DbType="Guid" Name="CreatedByUserId" PropertyName="UserId" />
        </WhereParameters>
    </asp:LinqDataSource>