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Notice: This page contains information for the legacy Phidget21 Library. Phidget21 does not support VINT Phidgets, and will not support any new Phidgets. Phidget21 will be maintained until 2020. We recommend that new projects be developed against the Phidget22 Library.


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Difference between revisions of "Language - Visual Basic 6.0"

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[[File:icon-Visual Basic.png|64x64px|link=|alt=Visual Basic 6.0]] Visual Basic 6.0, developed by [http://www.microsoft.com Microsoft] is a high level programming language that uses the COM programming model.
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Revision as of 16:39, 20 April 2012

Visual Basic 6.0, developed by Microsoft is a high level programming language that uses the COM programming model.

Introduction

If this is your first time working with a Phidget, we suggest starting with the Getting Started page for your specific device. This can be found in the user guide for your device. That page will walk you through installing drivers and libraries for your operating system, and will then bring you back here to use Visual Basic 6.0 specifically.

Visual Basic 6.0 is capable of using the complete Phidget API, including events. We also provide example code in Visual Basic 6.0 for all Phidget devices.

Visual Basic 6.0 can be developed with the Microsoft Visual Basic 6 IDE.

You can compare Visual Basic 6.0 with our other supported languages.

Quick Downloads

Just need the Visual Basic 6.0 documentation, drivers, libraries, and examples? Here they are:

Documentation

Example Code

Libraries and Drivers


Getting started with Visual Basic 6.0

If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:

  • Make sure your libraries are properly linked
  • Go from source code to a test application as quickly as possible
  • Ensure your Phidget is hooked up properly

Windows (2000/XP/Vista/7)

Description of Library Files

Visual Basic 6.0 programs on Windows depend on two files, which the installers in Quick Downloads put onto your system:

  • phidget21.dll contains the actual Phidget library, which is used at run-time. By default, it is placed in C:\Windows\System32.
  • Phidget21COM.dll is the Component Object Model(COM) library and provides your project access to the Phidget ActiveX objects. Your compiler has to know where this file is, by default our installer places this file into C:\Program Files\Phidgets, so you can either point your compiler to that location, or copy and link to it in a directory for your project workspace. If you are manually installing this file, you must register it through command line by running: regsvr32 Phidget21COM.dll.

If you do not want to use our installer, you can download both files and manually install them where you want; refer to our Manual Installation Instructions.

We include instructions on using our examples and writing your own code for the Microsoft Visual Basic 6.0 IDE.

Visual Basic 6.0

Use Our Examples

To run the examples, you first download the examples and unpack them into a folder. Here, you can find example programs for all the devices. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device.

1. Open up the .vbp project into the Visual Basic IDE.

2. Next, navigate to Project → Components to ensure that your project has access to the Phidget ActiveX objects

Components

3. The Components menu will show up. Ensure that the Phidget COM library is selected. If it is not, then browse for Phidget21COM.dll and add it. By default, it is placed in C:\Program Files\Phidgets. Accept the changes.

Library

4. Navigate to Project → References and ensure that the Phidget COM library is selected.

References

5. The only thing left to do is to run the examples! Click on Run → Start.

Run

Once you have the Visual Basic 6.0 examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget COM library. To begin:

1. Generate a new Standard EXE project.

New Project

2. Next, navigate to Project → Components to add the Phidget ActiveX objects into your project.

Components

3. The Components menu will show up. Browse for Phidget21COM.dll and add it. By default, it is placed in C:\Program Files\Phidgets. Accept the changes.

Library

4. Navigate to Project → References and ensure that the Phidget COM library is selected.

References

5. Navigate to Project → Project1 Properties, select the Make tab and ensure that the Remove information about unused ActiveX Controls checkbox is unchecked.

Unused ActiveX Controls

6. Then, you will need to declare and initialize the Phidget ActiveX object for your device.

The simplest method is to place the Phidget ActiveX object from the toolbox directly onto your form. If the toolbox is not present on your screen, navigate to View → Toolbox to show the toolbar. Next, find the ActiveX object for your device in the toolbox, and double click it to add it to the form.

Accessing Phidget ActiveX objects from the toolbox

Alternatively, you can dynamically create the Phidget ActiveX object in code. For example, for an PhidgetInterfaceKit, you would type:

Dim WithEvents PhidgetInterfaceKit As PhidgetInterfaceKit

Private Sub Form_Load()
   ...
   Set PhidgetInterfaceKit = Controls.Add("Phidget21COM.PhidgetInterfaceKit", "PhidgetInterfaceKit")
   ...
End Sub

The object name for each type of Phidget is listed in the COM API Manual. Please see the examples on how to add a reference to your particular Phidget.

The project now has access to the Phidget function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

Follow the Examples

By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want. This teaching section has resources for you to learn from the examples and write your own.

Next comes our API information, with syntax for all of our functions:

  • COM API Manual (This is the complete set of functions you have available for all Phidgets)
  • Device Specific APIs - The one for your Phidget can be found in its user guide.

To learn the details behind opening, configuring, using, and closing your Phidget, try the General Phidget Programming page. That page also describes using the Phidget in an event-driven manner and in a traditional manner, both of which are available in Visual Basic 6.0.

Example Flow

The Hello World example has this general structure so you can follow along. We also have an in-depth general introduction to writing Phidget code (like open, read data, etc), as well as the COM API Manual for specific syntax:

// ----- Event and Other Functions -----

Create any Language-Specific Functions (exception handling)

Create General Attach, Detach, and Error Handling Functions:

On attach: Print Hello Message
On detach: Print Goodbye Message

 

In Visual Basic 6.0, you can name these event functions whatever you like. You will then pass them as function pointers to the Phidget library below in the Main Code section. This hooks them into the actual events when they occur.
In the example code, the event functions common to all Phidgets are called things like AttachHandler() and DetachHandler(), etc.

Some event functions will be specific to each device, like when a tag is read on an RFID board, or when a sensor value changes on an Interface Kit. Other functions are given in the examples to show you more detail on using your Phidget. For example, DeviceInitialize() will show what needs to be set up for your Phidget before using it.

// ----- Main Code -----

Create Manager Software Object
Hook Event Functions created above to Device
Open Device

Wait for 'Enter' key character input
Handle on-going attach and detach events
Print Hello and Goodbye messages
Exit upon input

Close Device

Delete Device

 

Creating a Phidget software object in Visual Basic 6.0 is specific to the Phidget. For a Phidget Spatial, for example, this would involve creating a PhidgetSpatial object. The examples show how to do this and other API functions

Common Problems and Solutions/Workarounds

Windows: My application does not compile when a function contains more than one parameter.

In Visual Basic 6.0, the common way to handle multiple parameters is to not enclose the parameters with brackets. For example, instead of:

Object.getProperty(Parameter1, Parameter2)

You should write:

Object.getProperty Parameter1, Parameter2

If you wish, you can run the function with the parameters enclosed in brackets if you explicitly use the Call keyword when running the function. For example:

Call Object.getProperty(Parameter1, Parameter2)