With this in mind, here’s an infographic that illustrates how Xojo’s been continually updating and modernizing since 1996 while other development tools come and go.

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Show Notes

• Softbase Development
• A modern alternative to Visual Basic
• Migrating from VB to Xojo
• AlgoRhythms

There are three possible solutions to this problem:

1. Find a way to decrease the demand of mobile apps. (Good luck with that one.)
2. Increase the number of mobile developers.
3. Decrease the time it takes to build mobile apps.

Solutions 2 and 3 are not mutually exclusive. You could potentially do both. Adrian Leow even points to the solution when he suggests that developers use rapid mobile app development tools. These tools can provide solution 3, but they don’t create necessarily create more developers.

At Xojo, we have been building rapid application development tools for more than a decade so we know how to do it. Plus, we know how to make it easy enough that citizen developers (those that build apps but don’t have “developer” in their job title) can build the apps they need themselves. Xojo supports the ability to build native iPhone and iPad apps along with the ability to build web and desktop apps from a single IDE and language. Xojo is ideal for citizen developers as they often need desktop or web counterparts to their mobile apps. Anyone with experience in Visual Basic will find it quite easy to adapt to Xojo.

Xojo provides the combined solution that creates more developers by enabling citizen developers taking some of the burden off of IT and dramatically decreasing the development time of mobile applications.

First, let’s take a look at COM and its IDispatch interface. This interface is used by automation clients (like Xojo and VB) to access the COM component. At the high level view of this interface it is much like Introspection. The interface has methods to obtain a list of properties/methods that the COM component exposes and a way to Invoke them. For example, this is how one could use the ADO COM component to open a database connection using VB:

Dim Cnxn As Object
Set Cnxn = CreateObject("ADODB.Connection")
' Open connection
Cnxn4.Open("Pubs", "MyUserId", "MyPassword")

Under the hood, the Cnx4.Open call is communicating with the ADO component via IDispatch by looking up the “Open” method and Invoking that function if it exists. The equivalent Xojo code (without use of Operator_Lookup or ParamArray) would look something like this:

Dim Cnxn As New OLEObject("ADODB.Connection")

' Open connection
Dim params(2) As Variant  
params(0) = "Pubs"  
params(1) = "MyUserId"  
params(2) = "MyPassword"

Cnxn.Invoke("Open", params)

While functional, it doesn’t look or feel as nice as the VB equivalent. Enter Operator_Lookup. This operator overloads the class’s lookup operator. So whenever you call a method or property, for example Object.MyMethod, the Operator_Lookup is called with the name of the method or property (in this case “MyMethod”) passed as a parameter. By overloading this operator on the OLEObject class, you can now do something like this:

Cnxn.Open(params)

Underneath the hood the OLEObject implementation of Operator_Lookup looks something like this:

Sub Operator_Lookup(name As String, params() As Variant)
  Me.Invoke(name, params)
End Sub

Now that we’ve overloaded Operator_Lookup the next step to making this code look more like VB is to use ParamArray. By using a ParamArray, the user can now pass an indefinite number of parameters to the function without formally using an array. The final Operator_Lookup function would look something like this:

Sub Operator_Lookup(name As String, ParamArray params As Variant)  
  Me.Invoke(name, params)  
End Sub

Now our code can simply call Open with all the parameters supplied on the same line:

Dim Cnxn As New OLEObject("ADODB.Connection")
Cnxn4.Open("Pubs", "MyUserId", "MyPassword")

In conclusion, while ParamArray is more useful in the general sense, Operator_Lookup can be useful in situations like this where simplification makes sense. To round out our COM support we also had to add an OLEParameter class because it’s quite common in the COM world to pass parameters by name/position. So even though our compiler doesn’t support passing parameters by name, by using the OLEParameter class you can specify which parameters and their exact types to pass.

Feel free to post any questions here.

Xojo is the modern alternative to Microsoft Visual Basic. Xojo is a single language to build apps for Mac, Windows and Linux desktop, plus web, mobile and Raspberry Pi. Cross-compile desktop apps and use the same powerful language to develop for web and mobile too.

Develop Faster with Xojo

Xojo is more powerful than VB6 while at the same time more approachable than VB.NET. With Xojo, a single project can create desktop apps that work on Windows, macOS, Linux and Raspberry Pi. Unlike VB and Visual Studio, Xojo allows you to develop on your platform of choice- Windows, Mac or Linux.

Modernize Legacy Desktop Apps with Web and Mobile

Because Xojo can create apps for so many platforms, it is a great way to modernize and update your legacy desktop apps to web or mobile apps.

With Xojo, web apps are as easy to make as desktop apps. Use Xojo’s powerful language to create your web app instead of HTML, CSS, PHP, JavaScript, and AJAX and save tons of development time. Xojo web apps can be deployed to any server (Linux, macOS or Windows) and can also use the industry standard Apache web server.

These days mobile apps are often a necessity. Design your Xojo iOS apps using drag and drop in the layout editor, add your code and publish. Access the iOS-features you’d expect, like sharing panel and your photo library, and also the iPhone’s hardware-based features, like motion, location and camera. Xojo makes iOS development familiar and fast. Xojo Android is currently in development and will be testing soon.

Similarities between Xojo and Visual Basic

Language

The Xojo programming language is very similar to Visual Basic. It has commands like If..Then..Else, For..Next, and While..Loop. You will also find the object-oriented capabilities of Xojo quite similar to VB.NET.

Data Types

Xojo shares many of the same data types with VB6 and VB.NET, including: Integer, Double, String/Text, Currency, Boolean, Variant.

Controls

Xojo has many common controls including: Buttons, Labels, TextFields, TextAreas, ListBoxes (grids), PopupMenus, ProgressBars, toolbars and more.

Differences between Xojo and Visual Basic

Compiler and Run-time

Xojo apps are compiled to native code. They do not contain byte-code that is run by a virtual machine (as with .NET). The run-time library is included with your applications so there is nothing additional that needs to be installed on users’ computers.

Language and Framework

Xojo is fully object-oriented. Unlike VB6, you can have classes that use inheritance and other object-oriented features. The Xojo framework is designed to be simple to use and support cross-platform applications; it provides access to many things you’ve come to expect such as file handling, databases, graphics and more.

File I/O

One of the biggest differences between VB6 and Xojo is file I/O. Xojo consolidates all its file processing into a few classes: FolderItem, TextInputStream, TextOutputStream and BinaryStream. VB6 uses hard-coded file paths and less flexible file access methods, primarily because it only needs to work with Windows-specific file paths.

Data Types

Xojo is strongly typed, just like VB.NET. VB6 allows you to do some things the old-school, BASIC way, the most significant of which is using variables without declaring them (the type is inferred by a suffix on the name). Xojo does not allow this. Use the OPTION EXPLICIT command in all your Visual Basic code to have VB enforce explicit variable declarations.

Improved Error Handling

Xojo has modern exception handling using Try/Catch, Exception and App.UnhandledException.

Shared Libraries

Xojo cannot create DLLs, ActiveX controls, .NET assemblies or any kind of shared libraries. Since these are all Windows-specific technologies, that is somewhat understandable. You’ll either need to rethink your design or just re-use these components from within Xojo (and limit yourself to deploying only on Windows).

Switching to Xojo

Xojo is free for learning and development. Take your time to see how Xojo can help with your next project. Develop, run and debug your application with the free IDE, only purchase a license when you are ready to compile. Learn more about Xojo, read the User Guide and visit the Xojo Docs.

If you find yourself frustrated with VB.NET or are looking for something to replace VB6, be sure to test out Xojo. It might be just right for you. Watch the Migrating from VB video to see how a simple app is migrated to Xojo and visit our Migrating from Visual Basic page at the Xojo Docs for more details.

Updated June 2020