In Access VBA, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.

All these will work for variables unassigned, set to "", or set to Null:

If s&"" = "" Then
  MsgBox ("Quotes with &'' say null is empty")
End If

 
If Len(s&"") = 0 Then
  MsgBox ("Len with &'' says null is empty")
End If

If Len(s&vbNullString) = 0 Then
  MsgBox ("Using vbNullString also works!")
End If

Keep abreast of what's taking place in the world of Microsoft Office Access directly from the members of the Access Team.

Yes, you can either convert it to Access 2003 format or leave it as 2002 format and use it with Access 2003.

Same as VB. ASP Classic logical operators:

and	and, as in this and that
or	or, as in this or that
Not	Not, as in Not This

In ASP Classic, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.

Same as VB. The Me keyword is a built-in variable that refers to the class where the code is executing.

Class Cyborg
 Public CyborgName
 

 Public Function IntroduceYourself() 
  'Using Me. Prints Cameron.
  Response.Write("Hi, my name is " & Me.CyborgName & ".")

  'The above is just a demo. You could also not include "Me." 

  'in this case because we are in context of Me now. Using Me 

  'makes more sense when you start to pass Me as a parameter 

  'to a method.

 End Function 
End Class

C# is case sensitive. The following does NOT:

messagebox.Show("hello");  //Does not work!

The first time you type any other case for commands or variables, VS.Net will change it to the accepted or defined case. For example, if you type messagebox.show it is converted to MessageBox.Show. Once corrected, you can break it again by editing MessageBox to messagebox and the compiler will give you an error.

C# uses the keyword partial to specify a partial class. All parts must be in the same namespace.

A partial class, or partial type, is a class that can be split into two or more source code files and/or two or more locations within the same source file. Each partial class is known as a class part or just a part. Logically, partial classes do not make any difference to the compiler. The compiler puts the class together at compile time and treats the final class or type as a single entity exactly the same as if all the source code was in a single location.

You can use them for many things including to separate code generator code, organize large classes, divice a class up so you can split ownwership among multiple developers, have different versions of the same class, and to utilize multiple languages with a single class.

General Info: Round Floating Point Numbers

When comparing floating point numbers, make sure you round to an acceptable level of rounding for the type of application you are using.

Languages Focus: Comparison Operators

A comparison operator compares two values either literals as in "Hello" and 3 or variables as in X and Counter. Most languages use the same operators for comparing both numbers and strings. Perl, for example, uses separate sets of comparison operators for numbers and strings.

//Does C# evaluate the math correctly? No!

if (.1 + .1 + .1 == .3)
  MessageBox.Show("correct");
else
  MessageBox.Show("not correct");

You don't have to do anything special in your application. However, you do have to give certain folders and files the correct rights in your installer.

C++/CLI performs implicit casting of numbers to strings. To concatenate two strings, a string to an integer, or a string to a floating point number, use the + operator. For example, to convert a floating point number to a string just concatenate an empty string to the number as in "" + 3.2.

//Implicit casting of numbers.

//

//This fails:

//MessageBox::Show(3.3);

//

//This works:

MessageBox::Show("" + 3.3);

The concept of a class makes it possible to define subclasses that share some or all of the main class characteristics. This is called inheritance. Inheritance also allows you to reuse code more efficiently. In a class tree, inheritance is used to design classes vertically. (You can use Interfaces to design classes horizontally within a class tree.) With inheritance, you are defining an "is-a" relationship (i.e. a chow is-a dog). Analysts using UML call this generalization where you generalize specific classes into general parent classes.

Our most popular article in the history of our online community! Explains the "is a", "has a", "uses a", and "looks like" relationships (updated May 2007). "Is a" is inheritance, "looks like" is interfaces, "has a" is aggregation, and "uses a" is composition.

Download BDE 5.202 (includes a small BDE Information utility for testing the installation).

BDE 5.202 is the latest BDE and was released in 2001 (no updates since). Download Borland Database Engine (BDE) 5.202. This installation installs the BDE 5.202 plus a small utility program to test the installation called BDE Information utility.

The SerialPort class introduced in .NET 2.0 is definitely better than writing unmanaged Win32 API calls to access the serial port, but this is much better.

Without going into too much detail, a recent project of mine required that my application interface with an obscure device via RS232 and the serial port.

To do what I needed the device to do required me to manipulate the signal (high/low) on the RTS pin; the .NET framework's SerialPort class didn't really give me a mechanism for doing so.  Wanting to leave writing Win32 API p/invoke calls a last resort, the first result in a Google search for "better .NET serial port" led me to this article on CodeProject which described CommStudio's CommStudio Express which includes a much better serial port (SerialConnection) class which quickly enabled me to get past my little setback an on with the application. Best of all it's free!

I hope this referral link helps you.

This tutorial shows how you would create a trigger in Microsoft SQL Server 2005/2008 that will date/timestamp a column named last_updated everytime any data in the row is updated.

This example assumes a primary key that includes 3 fields.

CREATE TRIGGER MyTableUpdate
ON dbo.MyTable
FOR update
AS
UPDATE
MyTable
SET last_updated = GetDate()
From MyTable Inner Join Inserted On
MyTable.KeyField1 = Inserted.KeyField1
and MyTable.KeyField2 = Inserted.KeyField2
and MyTable.KeyField3 = Inserted.KeyField3

This page is a reference of the various Microsoft Certifications available to developers.

• Microsoft Certified Technology Specialist - Microsoft Certified Technology Specialist (MCTS) certifications enable professionals to target specific technologies and to distinguish themselves by demonstrating in-depth knowledge and expertise in the various Microsoft technologies with which they work.
• Microsoft Certified Professional Developer - The Microsoft Certified Professional Developer (MCPD) credentials distinguish you as an expert Windows Application Developer, Web Application Developer, or Enterprise Applications Developer.  These credentials demonstrate that you can build rich applications that target a variety of platforms using .NET Framework 2.0.
• Microsoft Certified Architect Program - Microsoft Certified Architect Program targets practicing solutions architects and infrastructure architects who successfully apply frameworks and methodologies to create an architecture through the entire IT lifecycle.
• Microsoft Certified Learning Consultant - The Microsoft Certified Learning Consultant (MCLC) credential recognizes MCTs whose job roles have grown to include frequent consultative engagements with customers. These MCTs are experts in designing and delivering customized learning solutions.
• Microsoft Certified Database Administrators - Microsoft Certified Database Administrators (MCDBA) design, implement, and administer Microsoft SQL Server Databases.
• Microsoft Certified Trainer - Microsoft Certified Trainers (MCT) are qualified instructors certified by Microsoft to deliver Microsoft training coursesto IT professionals and developers.
• Microsoft Certified Application Developers - Microsoft Certified Application Developers (MCAD) use Microsoft technologies to develop and maintain department-level applications, components, Web or desktop clients, or back-end data services.
• Microsoft Certified Solution Developers - Microsoft Certified Solution Developers (MCSD) design and develop leading-edge business solutions with Microsoft development tools, technologies, platforms, and the Windows architecture.

Literals are single quoted (the apostrophe) as in 'Prestwood'. If you need to embed an apostrophe use two apostrophies in a row.

ShowMessage('Hello');
ShowMessage('Hello Mike''s website.');

Having consistently formatted source code makes life so much easier.

At Prestwood, we are often asked to enhance, update, and maintain Delphi applications created by somebody else. Some of it is well formated; lots of it is just horrible. Before I even start trying to understand the existing code, I let DelForEx have a run at it. And, man, does it ever make a difference.

But it's not just handy for cleaning up somebody else's code. Often, while working on my own code, I'll rearrange blocks of code by cutting and pasting. Often the indentation is way off. DelForEx fixes it pronto.

DelForEx is a free plug-in for the Delphi IDE. Highly recommended. Combined with GExperts, it turns your IDE into a real powerhouse.

The simplest way to prevent the circular event firing is to check the form's ActiveControl property. This property indicates which component currently has the focus.

The OnChange event should read as follows:

procedure TForm1.EditChange(Sender: TObject);
begin
if TEdit(Sender).Name <> TEdit(ActiveControl).Name then
   begin
       // do processing
   end;
end;

Simple syntax example of class inheritance.

Both Eclipse 3.3 and JBuilder 2008 come bundled with Business Intelligence and Reporting Tools (BIRT). BIRT is an Eclipse-based open source reporting system with both a report designer based on Eclipse, and a runtime component that you can add to your app server plus a charting engine that lets you add charts.

You can test whether you have Java installed at http://www.java.com/en/download/help/testvm.xml.

The JavaScript event handler contains events centered around the Document Object Model (DOM). Common events include onMouseOver and onMouseOut, onFocus and onBlur, onClick and onDblClick, onChange and onSelect, onLoad and onUnload.

For example, onMouseOver and onMouseOut are frequently used with websites to change an image when your mouse moves over it. The onClick event is used to trigger code upon a mouse click.

In the following example, we use a standard image tag set to an image, change it on mouse over, then set it back on mouse out.

<img id="Image1" src="i_search.gif"

 onmouseover="document.images['Image1'].src='i_coat.gif';"

 onmouseout="document.images['Image1'].src='i_search.gif';">

javascript:MM_openBrWindow('http://www.prestwood.com/shop/purchase_orders.html', 'compare', 'scrollbars=no, resizable=no, width=600, height=420')

Chapter 12, "Handling Reports" from Paradox 9 Power Programming by Mike Prestwood.

In ObjectPAL, an empty variable can be unassigned (essentially null) or blank (equivalent to ""). You have to use both isBlank and isAssigned to check for an empty string.

var
 s String
endVar

;s = ""  ;Uncomment to test 2nd case.

if isBlank(s) or not isAssigned(s) Then
 msgInfo("", "empty string")
endIf

This AVI animation is for interactive Paradox users and demonstrates how to put lots of fields on a form using a text box.

WordPerfect Office 2000 for Linux

Mike Prestwood Chapter Contributions

ISBN: 0-07-212238-2
Mike Prestwood contributed four chapters to this book and although his contribution was 15% of the book, he did not receive author credit. Mike is briefly acknowledged in the Acknowledgments on page XXI as writing "most" of the Paradox material (he actually wrote all of the Paradox material).

• Linux Book Paradox Knowledge Base

Forward by Michael Cowpland

I think it is interesting to read the words Dr. Cowpland wrote back in 1999 and his excitement about supporting Linux. Too bad the financial bubble burst and he couldn't follow though.

Forward from book...

Does Paradox for Windows support .PNG image files?

Yes, Paradox 10 and 11 support .PNG graphics. For example, you can insert a .PNG using Edit | Paste From. However, Paradox 9 and earlier do not.

Note: All images stored in a Graphic field in Paradox tables are stored as uncompressed BMP images. This FAQ is about Paradox for Windows' ability to paste or import .PNG images into the .BMP formatted Graphic field type. For earlier versions of Paradox, you have to first convert the image.

Perl is case sensitive.

print "hello"; //This works.

Print "hello"; //This does not.

PHP uses a period (.) known as a dot to concatenate strings.

With PHP, you simply copy your files to a web server that is capable of running PHP pages.

Unlike Delphi, Prism performs implicit casting. To concatenate two strings, a string to an integer, or a string to a floating point number, use the + operator. For example, to convert a floating point number to a string just concatenate an empty string to the number as in "" + 3.2.

Prism supports both partial classes and partial methods using the keyword partial. A partial method is an empty method defined in a partial class.

In Prism, a string can be nil (unassigned), assigned an empty string (""), or assigned a value.  Therefore, to check if a string is empty, you have to check against both nil and (""). Alternatively, you can check the length of the string or use String.IsNullOrEmpty.

var s: String; 

if (s = nil) or (s = '') then
  MessageBox.Show("empty string");

or use length:

if length(s) = 0 then
  MessageBox.Show("empty string");

The obvious differences between Delphi Prism and C# are additional features in the Delphi Feature Pack (Blackfish SQL etc.) and the Object Pascal based syntax, which are very attractive for developers skilled in Delphi for Win32, for example. However, the compiler adds a wide range of extemely useful enhancements as well.

Can I run a Gigabit network over Category 5 or Category 5e?

No to CAT 5, or at least almost never. Yes to CAT 5e. Category 5e cable is enhanced over Category 5 to adhere to more stringent standards and is recommended over CAT 5 for speeds above 100 Mbps and up to 1 Gigabit.

However, Category 6 or 6a is recommended over CAT 5e because of it's even higher quality and some properly installed CAT 6 networks can support 10 Gigabit speeds. Although for 10 Gigabit, CAT 6a is recommended.

CAT 7 is rated for 10 Gigabit but supports up to 100 Gigabit.

Using real world scenarios when you write conceptual documentation for Software Development Kits (SDKs) is a way to give your readers ideas as to how the SDK can be used and to guide them as to what APIs are needed for commonly expected scenarios. This article guides you through how to gather information about scenarios, how to simplify them in order to make good examples, and how to lead developers through which APIs to use.

In VB Classic, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.

All these will work for variables unassigned, set to "", or set to Null:

If s&"" = "" Then
  MsgBox ("Quotes with &'' say null is empty")
End If

 
If Len(s&"") = 0 Then
  MsgBox ("Len with &'' says null is empty")
End If

If Len(s&vbNullString) = 0 Then
  MsgBox ("Using vbNullString also works!")
End If

In VB.Net, you specify a virtual method with the Overridable keyword in a parent class and extend (or replace) it in a descendant class using the Overrides keyword.

Use the base keyword in the descendant method to execute the code in the parent method, i.e. base.SomeMethod().

VB.Net uses the keywords sub and function. A sub does not return a value and a function does. Many programmers like to use the optional call keyword when calling a sub to indicate the call is to a procedure.

Class definition:

Public Class Cyborg

� Inherits Object

� Public Sub IntroduceYourself()

��� MessageBox.Show("Hi, I do not have a name yet.")

� End Sub

End Class

Some event like a button click:

Dim T1 As New Cyborg
T1.IntroduceYourself()

Free Vector Drawing Program.

Vector drawing software is more and more important as programs and web sites become more graphically demanding. Here we introduce two, free alternatives to the traditional - and costly - mainstays.

Windows Update installs new operating system features and fixes. Microsoft Update does that too but also updates some Microsoft products such as Office updates. Depending on which operating system you are using, you may already be using Microsoft Update. To check, go to Windows Update and check the settings for a Use Microsoft Update option or a checkbox that asks you if you wish to stop using Microsoft Update in favor of just using Windows Update.