In our Maine Microsoft Certification Study Group we recently had a discussion about using regular expression. Today I found myself writing a RegEx to check for illegal characters in a formula (string). I thought I’d share the solution:

private bool FormulaContainsIllegalCharacters( string formula )

{

    bool result = false;

    try

    {

        Regex r = new Regex( @"(!)|(@)|(#)|(\$)|(%)|(&)" );

        result = r.Match( formula ).Success;

    }

    catch { } // ignore any regular expressions errors -> return false

    return result;

}

In my case I’m not interested in handling exceptions. If a technical error occurs I will accept the input. Notice that I needed to put a “\” before the $ sign, since the $ is a reserved character marking the end of a line.
I don’t need to put each character in “( )” brackets, but for personal preference I just find it easer to read.

Whenever I need one I always need search for a good ASII table.

So here is one:

On June 26th the SDN will organize it’s quarterly Software Development Event in Hotel Houten (te Houten) in the Netherlands.

The speaker line-up is awesome (as usual), don’t miss it!

Sessions:

Sign up here: www.sdn.nl/sde

As owner of Develop-One I’m proud to announce that the Maine Quality Forum is now being hosted and serviced by Develop-One.

Visit the Maine Quality Forum site here.

Another little extension method. This one allows easy rounding to a specific number of decimals:

double d = 0.66782423;
string s = d.ToString(3);  // s = “0.668”

This is done by the following method:

public static class DoubleExtension

{

    public static string ToString( this double value, int decimals )

    {

        StringBuilder format = new StringBuilder( "0" );

        if ( decimals > 0 )

        {

            format.Append( "." );

        }

        for ( int i = 0; i < decimals; i++ )

        {

            format.Append( "0" );

        }

        return value.ToString( format.ToString() );

    }

}

I’ve been working a lot with the ReportViewer Control in Visual Studio 2008. The greatest part of the control is that you can implement reporting without using a database!

ReportViewer Control in Visual Studio 2008

ReportViewer is a freely redistributable control that enables embedding reports in applications developed using the .NET Framework. Reports are designed with drag-and-drop simplicity using Report Designer included in Visual Studio 2008 (Standard editon and above.)

See screenshots of some applications that have ReportViewer control embedded in them.

The ReportViewer control offers the following benefits:

• Processes data efficiently. The reporting engine built into ReportViewer can perform operations such as filtering, sorting, grouping and aggregation.
• Supports a variety of ways in which to present data. You can present data as lists, tables, charts and matrices (also known as crosstabs.)
• Adds visual appeal. You can specify fonts, colors, border styles, background images etc to make your report visually appealing.
• Enables interactivity in reports. You can have collapsible sections, document map, bookmarks, interactive sorting etc in your report.
• Supports conditional formatting. You can embed expressions in the report to change display style dynamically based on data values.
• Supports printing and print preview.
• Supports export to Excel and PDF.

The control can process and render reports independently using a built-in engine ('local mode') or it can display reports that are processed and rendered on a Report Server ('remote mode').

There is a WinForms and a WebForms version of the control.

Excellent tutorials on ReportViewer can be found at: http://www.gotreportviewer.com/

Back when .NET 1.1 was cool people would often use DateTime.MinValue to indicate that a date was actually empty. With .NET 2.0 can the Nullable<T> which allows you to create a nullable datetime. Ofcourse there is still plenty of old code out there, so when adding new code you may need to convert DateTime.MinValue to null. With extensions methods (.NET 3.5) you can implement an elegant solution.

The code below will allow you to write this:

DateTime old = DateTime.MinValue;

DateTime? current = old.ToNullable();

This is achieved with the following extension method:

public static class DateTimeExtension
{
    /// <summary>
    /// Examine the value of the DateTime, if the value is equal to DateTime.MinValue
    /// then the result is null, otherwise the supplied value is returned.
    /// </summary>
    /// <param name="value"></param>
    /// <returns></returns>
    public static DateTime? ToNullableDateTime( this DateTime value )
    {
        if ( value == DateTime.MinValue )
        {
            return null;
        }
        else
        {
            return value;
        }
    }
}

The leading event for C#, VB.Net, ASP.NET, DotNetNuke and Delphi developers is now open for registration!

For the 18th year running the Software Development Network will organize this 2 day event (on October 19th and 20th, 2009) with sessions about :

• .NET (C#, VB.Net, F#, etc.)
• User eXperience (ASP.Net, Silverlight, Expressions, Flash, etc.)
• Information Worker (MOSS, BizTalk, OBA, etc.)
• DotNetNuke (OpenForce Europe ’09 conference)
• Delphi
• Architecture
• Core Systems (C, Cobol, NonStop, IDMS, PL/1, DB2, CICS, TSO, ISPF, etc.)
• Databases

Don’t miss out! Click here to register.

Here is a shameless plug for my friend Mike who now has his own website at www.ireland-environmental.com.

If you need environmental services or help with getting the right permits to do construction and such, then Ireland Environmental Services is the place to go.
Mike is running a blog on environmental issues too, visit it here.

Today I had to fix a bug in some code involving a program creating multiple files where each file needed to have a unique machine generated filename. I was building my own unique name using the DateTime.Now.Ticks().ToString() as part of the name. Apparently on some machines the Ticks are not going to be unique. So I looked at the Path.GetTempFile() method, but I needed to control the location of the temporary files. Next stop: Path.GetRandomFileName().

Documentation:
The GetRandomFileName method returns a cryptographically strong, random string that can be used as either a folder name or a file name. Unlike GetTempFileName, GetRandomFileName does not create a file. When the security of your file system is paramount, this method should be used instead of GetTempFileName.

Works great!

We (the Maine Microsoft Certification Study Group) has been using Windows Live Groups as our virtual place to hang out. Out weekly meeting is posted on the group calendar, but the times kept showing up wrong on the overview page. As it turns out (thanks to Winston Natoli) there are three places where you can set the timezone:

Group Time Zone
- <Select Group or Access via Group Url>/ Options / Group Options/ General
Calendar Time Zone
<calendar.live.com>/ Options/ More Options / Time Zone
Live ID
<account.live.com>/ Registered Information/ Home Location/ Time Zone

After setting all of them to EST I’m now getting the right information.

Yeah, my last Training Kit is shipping!

Get a copy now at Amazon: http://tinyurl.com/dxwdz5

The documentation doesn't specifiy it but in the Entity Framework when you call ObjectContext.SaveChanges the update is 'wrapped' in a transaction.

NorthwindIBModel model = new NorthwindIBModel();

Guid id = Guid.NewGuid();

model.AddToCustomer(new Customer() { CustomerID = id, ContactName = "Andrew", CompanyName = "Northwind Traders" });
model.AddToCustomer(new Customer() { CustomerID = id, ContactName = "Aikido", CompanyName = "Northwind Traders " });

model.SaveChanges(); // exception duplicate key - transactional -> no changes to the database

Today I ran into a problem where apparently the registry settings for Visual Studio got messed up since I was no longer able to add a data connection in my Server Explorer, nor create an Entity Framework model from a database. Time to reset Visual Studio command(o) style.

To reset Visual Studio you open the Visual Studio Command Prompt and type:

devenv /resetsettings

And life is good...

On March 24th the Bangor .NET Developers will host an Ineta sponsored event where Steve Andrews will do a talk about the ASP.NET MVC Framework.

The ASP.NET MVC Framework provides a powerful Model View Controller (MVC) approach to building web applications, and provides separation of concerns, increased testability, control over HTML output, and intuitive URLs. We will start by looking at building a model framework with LINQ to SQL, including validation and model binding. Then, we'll explore a custom generics-based repository and services implementation. Finally, we'll tie it all together with a look at Views and jQuery.   Steve Andrews is a Team System MVP and INETA speaker, and has been working as a developer for more than 9 years. During this time, he has designed and developed applications in such widely varying areas as trust accounting, medical information management, supply chain management, and retail systems. Steve is also a MCTS, ICSOO, and community fanatic.   Go to www.bangordevelopers.com to sign up now.

The combined user groups of the SDN are putting together a terrific one day event with great sessions for software developers, architects, information workers and database professionals. Don't miss it!

Here is an overview of the sessions:

Go to www.sdn.nl/sde to sign up!

It often seems that management believes developers are highly exchangeable. Is an experienced developer leaving the team?

Then just new up a new .NET developer and you're done. This Dilbert episode reminded me of that attitude.

From www.dilbert.com

Once again the Maine Developer Network (thanks to John, Shawn and the State of Maine Government) is happy to help out Chris, Bob and Jim with finding a location to hold the MSDN Northeast Roadshow.

On March 19th the Roadshow will hit the Central Maine Commerce Center in Augusta. Go here to sign up today!

Location
Central Main Commerce Center
Florian Auditorium
500 Civic Center Drive Augusta Maine 04330
United States

Date
Thursday, March 19, 2009 8:30 AM - Thursday, March 19, 2009 4:00 PM Eastern Time (US & Canada)
Welcome Time: 8:00 AM