Server Error in '/' Application.
--------------------------------------------------------------------------------
Operator '==' incompatible with operand types 'Int32' and 'Object' 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
Exception Details: System.Web.Query.Dynamic.ParseException: Operator '==' incompatible with operand types 'Int32' and 'Object'
Source Error: 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  
Stack Trace: 

[ParseException: Operator '==' incompatible with operand types 'Int32' and 'Object']
   System.Web.Query.Dynamic.ExpressionParser.CheckAndPromoteOperands(Type signatures, String opName, Expression& left, Expression& right, Int32 errorPos) +487761
   System.Web.Query.Dynamic.ExpressionParser.ParseComparison() +577
   System.Web.Query.Dynamic.ExpressionParser.ParseLogicalAnd() +25
   System.Web.Query.Dynamic.ExpressionParser.ParseLogicalOr() +25
   System.Web.Query.Dynamic.ExpressionParser.ParseExpression() +22
   System.Web.Query.Dynamic.ExpressionParser.Parse(Type resultType) +25
   System.Web.Query.Dynamic.DynamicExpression.ParseLambda(ParameterExpression[] parameters, Type resultType, String expression, Object[] values) +45
   System.Web.Query.Dynamic.DynamicExpression.ParseLambda(Type itType, Type resultType, String expression, Object[] values) +67
   System.Web.Query.Dynamic.DynamicQueryable.Where(IQueryable source, String predicate, Object[] values) +62
   System.Web.UI.WebControls.DynamicQueryableWrapper.Where(IQueryable source, String predicate, Object[] values) +14
   System.Web.UI.WebControls.LinqDataSourceView.ExecuteSelectExpressions(IQueryable source, IDictionary`2 whereValues, IOrderedDictionary orderByOrderedValues, IDictionary`2 groupByValues, IDictionary`2 orderGroupsByValues, IDictionary`2 selectNewValues) +288
   System.Web.UI.WebControls.LinqDataSourceView.ExecuteSelectQuery(LinqDataSourceSelectEventArgs selectEventArgs, Object selectResult, Object table, Boolean storeOriginalValues) +327
   System.Web.UI.WebControls.LinqDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +457
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +19
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +142
   System.Web.UI.WebControls.ListView.PerformSelect() +57
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +73
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +82
   System.Web.UI.WebControls.ListView.CreateChildControls() +55
   System.Web.UI.Control.EnsureChildControls() +87
   System.Web.UI.Control.PreRenderRecursiveInternal() +44
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Control.PreRenderRecursiveInternal() +171
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +842

<%@ Page Title="All Photo Albums" Language="C#" MasterPageFile="~/MasterPages/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Default" %>
<%--    (R)DBying Technologies
--%>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cphMainContent" Runat="Server">
   <asp:UpdatePanel ID="UpdatePanel1" runat="server">
      <ContentTemplate>
   <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" 
      DataSourceID="LinqDataSource1" DataTextField="Name" DataValueField="Id">
   </asp:DropDownList>
   <br />
   
      <asp:ListView ID="ListView1" runat="server" DataKeyNames="Id" 
         DataSourceID="LinqDataSource2" onitemcreated="ListView1_ItemCreated">
         <ItemTemplate>
            <li style="">
               <%-- an image control to display the picure --%>
               <asp:Image ID="Image1" runat="server" 
                          ImageUrl='<%# Eval("ImageUrl") %>'
                          ToolTip='<%# Eval("Tooltip") %>' />
               
               <%-- a text to provide a description below the picure --%>
               <asp:Label ID="DescriptionLabel" runat="server" 
                  Text='<%# Eval("Description") %>' /><br />
               <asp:Button ID="DeleteButton" CommandName="Delete" runat="server" Text="Delete" />
            </li>
         </ItemTemplate>
         
         <EmptyDataTemplate>
            No data was returned.
         </EmptyDataTemplate>
         
         <LayoutTemplate>
            <ul class="itemContainer">
               <li ID="itemPlaceholder" runat="server" />
            </ul>
            <div style="">
               <asp:DataPager ID="DataPager1" runat="server" PageSize="3">
                  <Fields>
                     <%-- NextPreviousPager --%>
                     <asp:NextPreviousPagerField ButtonType="Button" ShowFirstPageButton="True" 
                        ShowLastPageButton="True" />
                     <%-- For Numeric Pager, uncomment the following --%>
                     <%--<asp:NumericPagerField NextPageText="..." PreviousPageText="..." />--%>
                  </Fields>
               </asp:DataPager>
            </div>
         </LayoutTemplate>
            
            
            
      </asp:ListView>
      
      <%-- comment --%>
      <asp:LinqDataSource ID="LinqDataSource2" runat="server" 
            ContextTypeName="LanicalDataContext" 
            TableName="Pictures" 
            Where="PhotoAlbumId == @PhotoAlbumId" EnableDelete="True">
            
         <%-- WHERE parameter(s):
          - ControlID    -- the control from which the parameter is taken for the WHERE clause
          - Name         -- the name of the PK column in the table of interest
          - PropertyName -- the corresponding value/parameter associated w/ the selected item in the drop down list, 
                              to replace @PhotoAlbumId, in the WHERE stmt above --%>
         <WhereParameters>
            <asp:ControlParameter 
               ControlID="DropDownList1" 
               Name="PhotoAlbumId" 
               PropertyName="SelectedValue" Type="Int32" />
         </WhereParameters>
      </asp:LinqDataSource>
      
      <%-- comment --%>
      <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
            ContextTypeName="LanicalDataContext" 
            Select="new (Id, Name)" 
            TableName="PhotoAlbums">
      </asp:LinqDataSource>
      
            </ContentTemplate>
   </asp:UpdatePanel>
</asp:Content>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
 

public partial class Default : BasePage
{
    protected void Page_Load(object sender, EventArgs e)
    {
    }
    protected void ListView1_ItemCreated(object sender, ListViewItemEventArgs e)
    {
       switch (e.Item.ItemType)
       { 
          case ListViewItemType.DataItem:
             Button deleteButton = (Button)e.Item.FindControl("DeleteButton");
             deleteButton.Visible=Roles.IsUserInRole("Managers");
             break;
          default:
             break;
       }
    }
}