Exploring the Visual Basic .NET Toolbox. full notes. 41pages.pdf

Exploring the Visual Basic .NET Toolbox Review and Preview • We have now learned the three steps in developing a Windows application and have been introduced to the Basic language. In this class, we begin a journey ...

Exploring the Visual Basic .NET Toolbox Review and Preview • We have now learned the three steps in developing a Windows application and have been introduced to the Basic language. In this class, we begin a journey where we look at each tool in the Visual Basic .NET toolbox. We will revisit some tools we already know and learn a lot of new tools. Examples of how to use each control will be presented. Function Overloading • As we delve further into Visual Basic .NET, we will begin to use many of its built-in functions for dialog boxes, drawing graphics, and other tasks. Before using these functions (we will use the MessageBox function soon), you need be aware of an object-oriented concept known as overloading. • Overloading lets a function vary its behavior based on its input arguments. Visual Basic .NET will have multiple functions with the same name, but with different argument lists. The different argument lists may have different numbers of arguments and different types of arguments. • What are the implications of overloading? What this means to us is that when using a Visual Basic .NET function, there will be several different ways to use that function. In these notes, we will show you a few ways, but not all. You are encouraged to use on-line help to investigate all ways to use a function. • Another implication is that, when typing code for a function, the Intellisense feature of the Visual Basic .NET IDE will appear with a drop-down list of all implementations of a particular function. As you type in your implementation, Intellisense adjusts to the particular form of the function it “thinks” you are using. Suggestions are made for possible arguments – it’s like magic! Sometimes, Intellisense guesses right, sometimes not. You must insure the implementation is the one you desire. If, after typing in a function use, Intellisense does not recognize it as proper usage, it will be flagged with an error indication (underlined) and you are given some direction for correcting the error. • Overloading is a powerful feature of Visual Basic .NET. You will quickly become accustomed to using multiple definitions of functions and how Intellisense interacts with you, the programmer.