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'+' sign in e-mails

Announcement: Plus signs in e-mail addresses ARE VALID! I can't tell you how many time I went to a blog, a forum, or a (poorly design web...)store and my e-mails didn't pass validation. On some blogs I even get ASP.NET exceptions.

Plus signs in e-mails are commonly used for sub-addressing. When you have an e-mail like help@gmail.com and you don't want to give that to a webstore you can simply hand out help+nospam@gmail.com or help+Amazon@gmail.com or whatever and you're still good.

So PLEASE... if you wrote a buggy application or script that disallows '+' in e-mail addresses, fix your bugs.

.NET 2.0 trycatch and trycatch(Exception ex)

One thing that I found rather interesting about .NET 2 that's different from .NET v1 is how v2 handles non-exception throwables differently.

First, a little background...

In case you don't know, the following two pieces of code are completely different.

try {
    Thrower.Start( );
}
catch (System.Exception ex) {
    System.Console.Write("Error!");
}
try {
    Thrower.Start( );
}
catch {
    System.Console.Write("Error!");
}

The difference is not that the first catches exceptions from unmanaged code and the second second doesn't, the first actually does catch those exceptions. The difference is also a bit more important than the mere fact that in the first one case we capturing the exception data in an exception type and in the other we aren't. The real difference stems from the fact that that in .NET you can throw things other than exceptions and in v1 you used the latter code to catch those non-exception throwables.

Here's an example of how to throw a non-exception. Yeah, you basically have to use the IL, or a compiler that doesn't check for this stuff.

// ThrowerLib.il
.assembly ThrowerLib { }

.class public Thrower {
    .method static public void Start( ) {
        ldstr "Oops"
        throw
        ret
    }
}

Here we are throwing "Oops". That's obviously a string, not something derived from System.Exception. In v1 you could use try{}catch(Exception ex) {} as a catch all for all exceptions, but that would not catch this error as it's not an exception. To catch this, you would also have a catch{} at the end.

OK, so how's v2 different? In this world, the non-exception item thrown is wrapped up in a real exception. So, in .NET v2 you can actually use your normal try {} catch(Exception ex){ } to also catch these non-exception throwables as well.

They are actually thrown as a RuntimeWrappedException. So the following app compiled an run in .NET v1 would explode into pieces, but would would gracefully end in .NET v2.

// ThrowerLib.il
.assembly ThrowerLib { }

.class public Thrower {
     .method static public void ThrowException( ) {
         ldstr "ThrowException exception from the IL world!"
         newobj instance void [mscorlib]System.Exception::.ctor(string)
         throw
         ret
     }

     .method static public void ThrowString( ) {
         ldstr "Weird exception!"
         throw
         ret
     }
}
// ThrowerHarness.cs
namespace ThrowerExample
{
    class ThrowerHarness
    {
        static void Main(string[] args) {
            try {
                Thrower.ThrowException( );
            }
            catch (System.Exception ex) {
                System.Console.WriteLine("System.Exception error: " + ex.Message);
            }
            catch {
                System.Console.WriteLine("Non System.Exception based error.");
            }

            try {
                Thrower.ThrowString( );
            }
            catch (System.Exception ex) {
                System.Console.WriteLine("System.Exception error: " + ex.Message);
            }
            catch {
                System.Console.WriteLine("Non System.Exception based error.");
            }
        }
    }
}

Cool SMS/VS2005 Integration Feature

Today I discovered a very wierd feature regarding SQL Management Studio 2005 ("SMS") and Visual Studio 2005 (of course I'm using the FREE standards editions from the MSDN/Technet seminars)

OK so here it is...

  • Open SMS
  • Navigate to a table and modify it.
  • Copy the text of one of the columns
  • Go to an ASPX page in Visual Studio 2005 and paste.

If you did it right you will see the weirdest thing in the world: it pastes a GridView linked to a SqlDataSource, which it also pastes.

<asp:GridView ID="GridView1" runat="server"
     DataSourceID="SqlDataSource2"
     EmptyDataText="There are no data records to display."
     AutoGenerateColumns="False">
    <Columns>
        <asp:BoundField DataField="ContactID"
            SortExpression="ContactID"
            HeaderText="ContactID">
        </asp:BoundField>
    </Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
    SelectCommand="SELECT [ContactID] FROM [Employee]"
    ConnectionString="<%$ ConnectionStrings:AdventureWorksConnectionString1 %>"
    ProviderName="<%$ConnectionStrings:AdventureWorksConnectionString1.ProviderName %>">
</asp:SqlDataSource>

You will also find that it pastes the appropriate connection string directly into your web.config.

<add
 name="AdventureWorksConnectionString1"
 connectionString="[string omitted;  it was LONG"
/>

Cool, huh?

p.s. If you want to paste that particular name, as I wanted to do, you can always do the old school paste-into-notepad-copy-out-of-notepad trick that is a tried and true way to strip off Web Browser formatting.

New Blog

In addition to my WinFX blog I'm also going to be working on this new dynamics blog, called Dynamic Bliss. This blog will cover client-side topics such as XML based, out-of-band procedure calling ("Ajax" though I don't approve of that name), ECMAScript dynamics, dynamic graphics, widget creation, other topics from my book and a few other browser-related topics.

This blog is the replacement of a book I was working on regarding the same topic. I'm a strong believer that blogging is the new book (for technology at the moment). Parts of the blog will include video chapters from the my video book as well as my Firefox Web Development Suite videos.

You can get to the blog here, Dynamic Bliss.

C# 2.0 Self-Test

In the .NET course I'm teaching (".NET Complete") I gave a little project to the class, of which all of them are new to OO design, C#, .NET, and all the related items. The project requirement was for them to study the example and see what it does. The point of the project was to allow them to test their knowledge of C# syntax, collections, generics, and nullable types

It's almost as useless as "Hello World". Or,rather, hello world is almost as useless as this.

You simply type in string and it tokenized it into characters...but they didn't know that.  Anyhow here you go...

using System;
using System.Collections.ObjectModel;
using System.Collections.Generic;

namespace CodeExamples
{
    class Program
    {
        class Storage<T> where T : ICollection<Char>, new( )
        {
            private Dictionary<String, T> list = new Dictionary<String, T>( );

            public void ShowLines( ){
                Int32? i;
                foreach(KeyValuePair<String, T> collection in list) {
                    i = null;
                    if(collection.Key.Length > 2) {
                        i = collection.Key.Length;
                    }

                    Console.Write((i ?? -1) + " : " + collection.Key + " : ");
                    foreach(Char thing in collection.Value) {
                        Console.Write(thing);
                    }


                    Console.WriteLine();
                }
            }

            public void Save(String text) {
                T parts = new T( );
                foreach(Char c in text.ToCharArray( )) {
                    parts.Add(c);
                }

                if(!list.ContainsKey(text)) {
                    list.Add(text, parts);
                }
            }
        }

        static void Main(String[] args) {
            Storage<Collection<Char>> storage = new Storage<Collection<Char>>( );

            Boolean done = false;

            while(!done) {
                String text = Console.ReadLine( );

                if(text == "end") {
                    done = true;
                    continue;
                }

                storage.Save(text);
            }

            storage.ShowLines( );
            Console.ReadLine( );
        }
    }
}