PeterKellner.net » .Net 2.0

Silicon Valley Code Camp Login Failing with IE10 (Fixed Now)

Peter Kellner — Tue, 20 Sep 2011 17:10:29 +0000

Scott Hanselman posted a while back about a browsers definition problem with some ASP.NET sites that causes problems. Microsoft has articles on this also. Having just received my BUILD tablet that includes IE10, I tested the Silicon Valley Code Camp web site and discovered that when you login, then switch to another page, the login did not stick. After uploading the two files Scott mentions (firefox.browser and ie.browser), the problem goes away.

Thanks Scott for the heads up.

With ASP.NET WebForms, How to Keep / Stop a Data Control Like GridView From Retrieving Data

Peter Kellner — Mon, 01 Aug 2011 21:35:00 +0000

The What and Where

Something that may not be obvious is if are creating an asp.net WebForms project and you put a datasource such as SqlDataSource or ObjectDataSource for example on the page, how can you prevent the SqlSelect associated with that datasource from being triggered.

The answer is to set the control’s visible property to false. That’s it!

The Why

The reason you might want to do this is for a case where you have a public facing web page that might be easily subjected to a denial of service attach. If that web page is always causing some SqlDataSource to fire, you could easily find your SqlServer overloaded. At least by checking to see a user is logged in before firing the sql statement, you buy yourself a little bit of protection.

The Code

<%@ Page Language="C#" %>

DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void 
        GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {

    }

    protected void Page_Init(object sender, EventArgs e)
    {
        if (!Context.User.Identity.IsAuthenticated)
        {
            GridView1.Visible = false;
        }
    }
script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>title>
head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="<%$ ConnectionStrings:CodeCampSV06 %>" 
            SelectCommand=
            "SELECT [Id], [Username], [Email] FROM [Attendees] ORDER BY [Id] DESC">
            asp:SqlDataSource>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
            DataKeyNames="Id" DataSourceID="SqlDataSource1" 
            onselectedindexchanged="GridView1_SelectedIndexChanged">
            <Columns>
                <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" 
                    ReadOnly="True" SortExpression="Id" />
                <asp:BoundField DataField="Username" HeaderText="Username" 
                    SortExpression="Username" />
                <asp:BoundField DataField="Email" HeaderText="Email" 
                SortExpression="Email" />
            Columns>
        asp:GridView>
    div>
    form>
body>
html>

Adding a List of Recent Posts To The Silicon Valley Code Camp Home Page (From RSS Feed)

Peter Kellner — Sun, 12 Sep 2010 21:44:26 +0000

There are 10,000 ways to do this. Back way back when (ASP.NET 1.1) days, we would have created either a custom control to do this, then added a Repeater control on the page to display it. Well, the Silicon Valley Code Camp Website was started back in those days and since what I want is so simple, I decided to do just that (minus the custom control). I really only wanted to spend about 10 minutes doing this, and as it turned out, it took about 30. Oh well, 3x plan verses execution. Could do better next time.

So, here is basically what I want on the left side bar of the home page of Silicon Valley Code Camp:

First, I’ll attach my simple project I build to do this standalone so you can run it yourself, then, I’ll do a quick step through of the key code.

SimpleRSSReaderJustTitleAndLink.zip

All that is really in this project is a simple c# class file that contains a business object and one get method to retrieve the list. That file is called RSSFeed.cs. I’ve pasted all the code of that class below:

using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Xml.Linq;

namespace App_Code
{
    [DataObject(true)]
    public class RSSFeedObject
    {

        [DataObjectMethod(DataObjectMethodType.Select, true)]
        public List Get(int numberToGet)
        {
            XDocument feedXML = XDocument.Load
              ("http://blog.siliconvalley-codecamp.com/feed/");

            var feeds = feedXML.Descendants("item").
                Select(feed => new
                   {
                       PostTitle = feed.Element("title").Value,
                       PostURL = feed.Element("link").Value
                   });
            var rssItems = new List();
            int id = 0;
            foreach (var rec in feeds)
            {
                rssItems.Add(new RSSItem
                                (id,rec.PostTitle,rec.PostURL));
                id++;
                if (id >= numberToGet)
                {
                    break;
                }
            }
            return rssItems;                    
        }

    }

    public class RSSItem
    {
        [DataObjectField(true)]
        public int Id { get; set; }

        [DataObjectField(false)]
        public string PostTitle { get; set; }

        [DataObjectField(false)]
        public string PostURL { get; set; }

        public RSSItem(int id, string postTitle, 
                       string postURL)
        {
            Id = id;
            PostTitle = postTitle;
            PostURL = postURL;
        }
    }
}

Then, in the Default.aspx page, you can simply reference this object with a Repeater and an ObjectDataSource and you are done! That is it, very simple. Below is the page code.

<asp:ObjectDataSource ID="ObjectDataSourceRSS" runat="server"
   SelectMethod="Get" TypeName="App_Code.RSSFeedObject">
   <SelectParameters>
       <asp:Parameter DefaultValue="5" Name="numberToGet" Type="Int32" />
   SelectParameters>
asp:ObjectDataSource>
<asp:Repeater ID="RepeaterRSS" runat="server" DataSourceID="ObjectDataSourceRSS">
   <HeaderTemplate>
       <ul>
   HeaderTemplate>
   <FooterTemplate>
       ul>
   FooterTemplate>
   <ItemTemplate>
       <li>
           <asp:HyperLink ID="HyperLinkURL" runat="server" 
               NavigateUrl='<%# Eval("PostURL") %>'
               Text='<%# Eval("PostTitle") %>'>asp:HyperLink>
       li>
   ItemTemplate>
asp:Repeater>

I’m sure someone is going to point out how this could have been done in three lines of code. Until then, I’ll keep this in the Silicon Valley Code Camp site.

BTW, if the site looks different, it’s because a wizard html/css guy has come by and cleaned it up to look good. What you see in the top screen shot is what it looks like without any formatting. Just unordered list and listitems with no formatting.

HTH’s!

ReSharper 5.0 Adds New “Add Parameter” Refactoring

Peter Kellner — Mon, 26 Apr 2010 18:38:40 +0000

In this post, I’ll show a simple example of how when you add a parameter to C# method, ReSharper gives you a simple prompting to ask if you want to add a parameter to your method, or create an overloaded method that gives you the flexibility to maintain the old method signature and have the new method.

In my original code, I had the following code that called the method GetLoadResultsFromInterval.

List<LoadResult> loadResultsForInterval =
    GetLoadResultsForInterval(rec.TimePoint,
                              rec.IntervalLengthInMs);

Then, I simply added one more parameter (loadFtpArrivalTimeDictionary) and ReSharper prompted me with the following:

If I choose the first “Add Parameter, I get what I would expect, which is just the method with an extra parameter.

/// summary>
/// <param name="timePoint">param>
/// <param name="intervalLengthInMs">param>
/// <param name="loadFtpArrivalTimeDictionary">param>
/// <returns>returns>
private static List<LoadResult> 
   GetLoadResultsForInterval(DateTime timePoint, 
   int intervalLengthInMs, 
   Dictionary<string, DateTime> loadFtpArrivalTimeDictionary)
{
   throw new NotImplementedException();
}

It even adds the param xml definition automatically.

However, I’m not quite as pleased with the second refactoring, that is, “Create Overload”. It does almost everything I would expect, but does not implement the method, which I think it could. Or, at least it could give it a try. What it does implement is the following:

I’m actually including a picture of it rather than the actual code because it created an error. It should have said DateTime instead of loadFtpArrivalTimeDictionary. Two other things of interest.

First, it did not add xml comments (which is probably because of the syntax error), and second, I would have expected it to have called the overloaded method as follows instead of what it did.

private static List<LoadResult> GetLoadResultsForInterval(DateTime timePoint,
    int intervalLengthInMs, 
    Dictionary<string, DateTime> loadFtpArrivalTimeDictionary)
{
    // - put additional code here
    return GetLoadResultsForInterval(timePoint, intervalLengthInMs);
}

(before anyone points out this is the opposite of how you would normally overload a method call, I do know that. That is, typically, you would have a method with 2 incoming parameters that internally would call a method with 3 internal parameters, and you would simply default the third parameter. In my case, I’m going the other way, which is unusual, but not unheard of.)

I began this post to brag about yet another awesome ReSharper refactoring because I really just wanted to add a parameter to an existing method call and it worked perfect. It was not until I decided to show the other refactoring for this blog post did I run into the problem.

I’m going to post this to the refactor dev’s and see if they can let me know where either I’ve gone astray, or there is a problem in their code. At any rate, I’m running this on vs2008 and have not tried it on vs2010.

Hope this helps!

OData Query Option top Forces Data To Be Sorted By Primary Key

Peter Kellner — Wed, 31 Mar 2010 18:24:31 +0000

I’ve recently started using Microsoft’s WCF Data Services which supports OData Services. What this means is that we can access resources by simply specifying a URI. This concept greatly simplified building an ORM layer on a web site, as well as creating the linkage between the server side data and the client side application, which in my case is usually a browser.

So, the issue this blog addresses is that if you form a URI with the parameter $top={anything}, your data will automatically be sorted. The documentation for OData on top basically says that, but it could be clearer. It says the following:

“If the data service URI contains a $top query option, but does not contain a $orderby option, then the Entries in the set needs to first be fully ordered by the data service.”

What actually happens is when you use the orderby clause, the data will be sorted 100% of the time for you, whether you do it or not.

I put a small example together that shows that. I’ll briefly step through the parts of the code attached to this post that show that happening. First, the results:

Here is the actual Visual Studio 2010 RC project you can run yourself:

Solution: WCFServicesWithODataExample.zip

Notice that when $top=5 is called, the data returned is sorted by the primary key.

Now, here are the details of the project that shows this happening.

Below is the complete code for the WcfDataService.svc. Notice that the data is created in the SampleDataSource constructor and is created in non-key order.

using System;

using System.Collections.Generic;

using System.Data.Services;

using System.Data.Services.Common;

using System.Linq;

using System.ServiceModel.Web;

using System.Web;

namespace WebApp

    [EntityPropertyMappingAttribute(

        "Title", SyndicationItemProperty.Title,

        SyndicationTextContentKind.Plaintext, true)]

    [DataServiceKey("Id")]

    public class SampleInfo

        // The DataServiceKey attribute is necessary unless you name

        // this ID

        public int Id { get; set; }

        public string Title { get; set; }

    public class SampleDataSource

        private readonly List _sampleInfoList;

        public SampleDataSource()

            _sampleInfoList =

                new List()

                        new SampleInfo {Id = 3, Title = "3"},

                        new SampleInfo {Id = 4, Title = "4"},

                        new SampleInfo {Id = 1, Title = "1"},

                        new SampleInfo {Id = 5, Title = "5"},

                        new SampleInfo {Id = 2, Title = "2"}

};

        public IQueryable SampleInfoData

            get { return _sampleInfoList.AsQueryable(); }

    public class WcfDataService : DataService

        // This method is called only once to initialize service-wide policies.

        public static void InitializeService(DataServiceConfiguration config)

            config.SetEntitySetAccessRule("*", EntitySetRights.AllRead);

            config.SetServiceOperationAccessRule("*", ServiceOperationRights.All);

            config.DataServiceBehavior.MaxProtocolVersion =

                DataServiceProtocolVersion.V2;

I’ve created a very simple web page that includes some simple JavaScript to display the results of calling this WCF DataService with and without $top. The page code is below.

<head runat="server">

    <title>Demonstration of OData Sort Based on Using $toptitle>

     <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.3.2.min.js"

        type="text/javascript">script>