Bits & Pieces

Manage Terminal Services Sessions from a Command Prompt

2008-08-02T20:19:22.4161073-07:00

Tonight I had a few orphaned sessions to a remote machine that were not being enumerated by Terminal Services Manager or a remote connection (from Computer Management). I almost gave up and drove to the physical machine, but I found this trick online first.

Here's a handy way to view and manage sessions from the command prompt.

To List All Sessions

Start->Run->cmd

query session /server:xxx.xxx.xxx.xxx

To End a Session

Start->Run->cmd

reset session 1 /server:xxx.xxx.xxx.xxx

Note that "1" represents a session id. You can see all available sessions from the previous "query" command. Insert the correct number to terminate it.

Once you know these few commands, its actually quicker to manage remote sessions from the command prompt.

- Tim Medora

MaxDB Access with ODBC

2008-07-25T13:19:54.7419954-07:00

Little tip I thought I'd share...as of the date of this posting (7/2008), when building connection strings to access a MaxDB instance, the password must be changed to all uppercase.

For anyone who's wondering, it is possible to connect to MaxDB with ASP.Net/C#. Use the System.Data.Odbc library and a DSN to connect with only a few lines of code.

- Tim Medora

Ambiguous SQL Server 2005 Error - And One Solution

2008-05-26T14:50:51.297-07:00

Today I was happily coding a .Net 3.5/SQL Server 2005 web application when things came to a grinding halt with the error:

A severe error occurred on the current command. The results, if any, should be discarded.

I googled the error (of course), but found a dozen different answers and many of them required installing service packs or hotfixes. While I'm not opposed to that, I knew that it shouldn't be necessary.

I'm sure there are many causes for this error, but here was mine:

BEGIN TRANSACTION;

BEGIN TRY

    IF( @UserId < 1 ) BEGIN

        IF( (SELECT count(UserId) FROM [User] WHERE Email = @Email) > 0) BEGIN
            SET @Status = 1;
            RETURN;
        END

...

See the problem? I'm returning without committing or rolling back my transaction. While this is a stupid mistake on my part, the error message is quite ambiguous, but thankfully the solution is simple. Before returning, insert cleanup GOTO cleanup such as:

BEGIN TRANSACTION;

BEGIN TRY

    IF( @UserId < 1 ) BEGIN

        IF( (SELECT count(UserId) FROM [User] WHERE Email = @Email) > 0) BEGIN
            SET @Status = 1;
            GOTO NoSuccessReturn;
        END

...

NoSuccessReturn:
    IF( @@TRANCOUNT > 0 )BEGIN
        ROLLBACK TRANSACTION;
    END

    RETURN;

Hope this helps someone!

--Tim Medora

Disabling Inheritance in Web.Config Files

2008-05-05T19:38:57.795-07:00

Most ASP.Net developers quickly learn that web.config file settings percolate from the top down. This is commonly used to provide global configuration for a single web application, but it's pretty easy to forget that web.config settings can be inherited across different virtual directories.

For example:

1) Create a website in IIS.
2) Create a virtual directory for a second site underneath the IIS website.
3) Reference a type in the web.config for site #1, such as in a HttpHandler block.
4) Unless the second site has the type referenced in #3 (or it is in the GAC), second site will now immediately throw an exception, "Cannot load type xxx.xxx.xxx".

In web.config #1
<

httpHandlers >
< add verb = " GET " path = " *.css.ashx " type = " NFC.PublicWeb.UILogic.PathResolver,NFC.PublicWeb " />
httpHandlers >

This issue is caused because every virtual directory underneath the top-level website is inheriting settings from the top-most web.config. Many of these inherited settings would go unnoticed, but as soon as the child virtual directory hits something it can't handle, it immediately throws a show-stopping (as all config errors are) exception.

Quick Solution?
Wrap application specific blocks of code in the LOCATION tag. Obviously this must be used judiciously, but it's a useful fix to a sneaky problem.

location path = " . " inheritInChildApplications = " false " >
   < system.web >
      <httpHandlers>
         <addverb="GET"path="*.css.ashx"type="NFC.PublicWeb.UILogic.PathResolver,NFC.PublicWeb"/>
      httpHandlers>
   system.web>
location>

For a detailed discussion of this topic, see this useful article on www.aspdotnetfaq.com.

Determining if an Object's Data is Dirty

2008-05-02T16:13:36.405-07:00

Check out this brief whitepaper by Chris Szabo on a more elegant way of determining if the data encapsulated by an object is dirty or not.

Typical practice is to always save the object, dirty or not, which can be wasteful in a high-traffic scenario. Alternatively, many developers maintain an IsDirty flag, which does the job, but isn't that elegant. It also doesn't account for data that has "changed" but might actually be the same, such as when a user enters a value into a field that is bound to an object, and then undoes the operation.

http://www.netfusioncorporation.com/Downloads/2008/Intelligent%20Data%20Persistence.pdf

- Tim Medora

A Year of Vista

2008-04-18T11:44:26.36-07:00

Actually, it's been more than a year... alot more. But a year ago Processor Magazine interviewed me for my opinion on Windows Vista.

http://www.processor.com/editorial/article.asp?article=articles%2Fp2915%2F20p15%2F20p15.asp

I'm sure everyone is dying to see what I had to say.

A year later, I'm pretty much of the same opinion... I've survived and haven't had any major problems. Throw a powerful computer at it, and it isn't half bad.

- Tim Medora

Visual Studio 2008

2008-04-15T23:07:42.054-07:00

Visual Studio 2008 has been good to me so far.

I'm running:

- VS2008 Team System Developer Edition
- Windows Vista Enterprise
- Mac Pro dual duo-core Xeon 64-bit, 2GB RAM, 10K SATA HD, ATI Radeon x1900

If anyone is considering upgrading, here's my two cents:

PROS

- clean as ever, as fast or faster than previous versions
- new project template types
- painless to switch between different versions of the .Net framework
- supports cool new stuff like Linq & Silverlight
- seems very stable; I've used it heavily for about 2 1/2 months now.
- drawing issues that plagued Vista combined with VS 2005 seem to be gone.
- plays nicely with VS 2005 on the same machine.

CONS

- can't open a 2003/2005 project without converting it... this can be a deal breaker unless you are the only one on a project, or the whole team has upgraded. Make sure not to upgrade a project and check it back into source control unless you are the owner of that code and everyone else using that project knows about it.
- I have seen one error dialog popup repeatedly: "Cannot connect to undo manager". I haven't see any negative side effects of this error, other than it is annoying to get the dialog (possibly once or twice during several hours of usage).

Recommendation... if you get the chance to install it, go for it. You can always continue to use VS 2005 for day to day work and try out some of the new features of the 3.5 framework.

- Tim Medora