LINQ to Entities seems really great. It can save you a lot of time in writing unnecessary db connection code, improve the performance many fold, only connect to the db when required (lazy loading), and easy concurrency handling for you.

However there is a missing feature which I found out the hard way. If you try to do a ‘Create Function Import’ and it returns a scalar, the code will not be automatically generated, due to ‘lack of time’ from the MS Team:

MSDN Forums – See the post by Noam.

So basically, you are handicapped! Either write the code yourself or just do it the old fashioned way

Due to a recent agreement between Google and some book publishers, they are going to publish a large number of books online (limited content depending on each publishers agreement).

So you can now read Pro ASP.NET 2.0 C# for free online (a large chunk of it)!  Click the link for more.  This book is jam packed (1000 pages+) with well-written details on everything under the sun in .NET 2.0.  I was in particular looking for SQL Cache Dependency information which I found in there.

Apparently in SQL Server 2000, Cache Dependency is done on a table basis, you cannot have it dependent on a certain condition (for example select * from CONTACTS where location=’canada’).  If any data at all changes inside CONTACTS then the cache is considered invalidated and you will need fresh data.   Lots of improvements in SQL Server 2005 boys….

Spring is a popular framework available in Java.  It has also been published in .NET and is called Spring.NET

This framework is huge, but what I wanted to focus on is the section that deals with transaction management.

If you have ever worked with Transactions, (say SQLTransactions), you would realize how messy it can be when you have to keep your connection open and pass around a transaction to many different functions that are making updates or queries, and then you might make a small little change and find out you forgot to use the transaction object and you caused a deadlock!

How can you fix this?  By having a generic transaction/connection object?  Well, that’s one way.. but how about using the Spring.NET framework to deal with the transactions?

Spring.NET allows you to specify when you need a transaction, and you would begin and end the transaction.  However, when you do the actual database calls, you would not pass any connection string, it would automatically use the transaction in process if there is one, or if not needed then it would use a regular connection and disconnect after the query is complete.

Here is a code snippet to demonstrate programmative transaction management, taken from the Spring.NET source code (yeah its open source!)

[Test]
        public void ExecuteTransactionManager()
        {
            DefaultTransactionDefinition def = new DefaultTransactionDefinition();
            def.PropagationBehavior = TransactionPropagation.Required;

            //TODO change to property of name TransactionStatus...
            ITransactionStatus status = transactionManager.GetTransaction(def);

            int iCount = 0;
            try
            {
                iCount = (int)adoOperations.ExecuteScalar(CommandType.Text, "SELECT COUNT(*) FROM TestObjects");
                /*
                IAdoCommand cmd = new AdoCommand(dbProvider, CommandType.Text);
                cmd.CommandText = "SELECT COUNT(*) FROM TestObjects";
                iCount = (int)cmd.ExecuteScalar();
                */

                //other AdoCommands can be executed within same tx.
            } catch (Exception e)
            {
                transactionManager.Rollback(status);
                throw e;
            }
            transactionManager.Commit(status);
            Assert.AreEqual(2, iCount);

        }

As you can see from this code, the adoOperations.ExecuteScalar does not have any connection string passed to it.  Same thing with ExecuteDataSet, and so on. 

This actually saves you a lot of headache, as you just have to make sure you use the spring DataOperations object.  The easiest way to implement this on a ASP.NET site is to put these objects as a static variable and initialize them on Application_Load.  Just an idea but it should work. 

 If you want to do more digging, Spring.NET has tons of stuff, it seems to mostly focus on Dependency Injection and loose coupling of code from objects from the data layer.  I really like it and I recommend you give it a shot.

It’s proven itself in Java and I think this framework is going to prove itself in .NET as well.  At the very least the source code is a prime example of a clean object oriented well designed application with full unit tests and sample code, XML documentation, thorough use of interfaces and inheritance, and even ORM (object relational mapping) using NHibernate (again a popular Java framework which has come into .NET)

 Update: I called this "declarative transaction management", actually its "programmative transaction management". – FIXED

If you are tired of the headaches of using VB.NET code, and want to convert it to C#.. Here is a nice way to do it and get the comments too. 

Why would you do that?  Well if I have to explain to you, then you probably don’t need to do it.  One big reason for me is that VB.NET does not support multi line strings.  You have to keep putting " & _  at the end of each line making it very difficult to go back and forth from another program with strings.  You could technically create a tool to do this for you but that’s so silly.   Another thing is I really like using ?? operator in C#, for example txtLocation.Text = (GetLocation() ?? "").ToString() will ensure that even if SomeFunction returns null, this will always give you at least empty string..  I like to use this in cases where I am getting null and its a text box I am setting the text for.

Another reason is that VB.NET code doesn’t force you to type your variables properly, so everything is an object unless you specify, or unless you put on Option Strict

One way to do it is to use Reflector + Code generation add-in, but you will lose the comments and maybe even variable names because it uses the intermediate language (IL) from the DLL to re-make the source, so it’s pretty useless to do it this way if you want to keep your code in the long run.

The way I like is to use a site such as http://labs.developerfusion.co.uk/convert/vb-to-csharp.aspx

Keep in mind I know there are other tools available that you can pay for, and some that are free too, but this is a quick and easy way to do it at work without requiring any installation.

Once you perform the conversion, the code will still have some things that need to be manually converted.
One thing is this site does not compile the code, so it does not know if the VB code .Rows(5) is actually a function call called Rows with a parameter 5, or its an array index [5].  So you will need to fix these manually.

Same thing with Tables[], Session[], etc.
Sometimes with VB code you will see .Item being used when no such thing exists in C#, you just use the square brackets to get the item directly such as .Rows.Item(5) in VB.NET is equal to .Rows[5] in C#

Here is how you can search and replace these with a regular expression.

Search: \({(["|a-z|A-Z|,|0-9|\:|\.|_])+}\)

Replace: [\1]

You have to do this manually and confirm each one.. Or make it more smart by searching for keywords such as QueryString, Cookie, Value, etc.. and replace all, then do the rest manually

The next thing is that functions such as .InStr are not supported directly from C#, you need to call Microsoft.VisualBasic.Strings.InStr(…)   The code converter will automatically do this, but you need to add using Microsoft.VisualBasic.Strings to the top of your class file.

There are a few more things I could mention, but just try it out and see how it goes.

Here is a few more things
1) "my string" & " is very long" will give an error while converting. Before you run the converter, replace these & in your VB code with + instead.
2) the functions that have handles such as lstItems_SelectedIndexChanged(…) handles lstItems.SelectedIndexChanged need to be taken care of by putting either an event in the ASPX page in the <DropDownList OnSelectedIndexChanged="lstItems_SelectedIndexChanged"

Also, they might be private, so you need to make them protected.  Here’s a regexp to start you off:
find: {(protected|private)} void {(lnk|lst)}
replace with: public void \2

3) Functions that have optional parameters need to be taken care of.  An easy way to take care of this is to create another function that calls the second one that passes the default value with the same name. That easy!

By the way, since I am not regularly writing here, I would suggest you subscribe to my feed so you can get an update when I post a new article.

Let’s say you are using a 3rd Party Library like ELMAH in your web site project to handle unhandled exceptions and it’s throwing an exception and you don’t know why.  Since the code is open source, you would LOVE to see what line its crashing on and then submit your changes to the project so that others can benefit from the fix you made.  It gives you that good feeling, right?

Well, unfortunately, you put the compiled DLL in the bin folder and when it crashes, it just crashes and burns.

How can you see the source code?  Simple!  Compile the source code on your machine, and copy the PDB ("Debugging Database") file to your bin folder along with the DLL, and then your web site crashes while in debug mode, it will go to the exact folder on your file system where the DLL was compiled from and show you the exact line of the error.

This was my recent experience with Elmah that it was crashing due to the fact that XMLWriter was misbehaving and throwing an exception when it was supposed to actually replace invalid entities in the XML automatically (at least, according to the MSDN documentation).

Take a look at Issue 43 on Elmah Site for more details.