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This article mainly introduces the example analysis of the scope of application of VB.NET variables, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian take you to understand it.

The scope of application of VB.NET variables defined in the program is different from that in VB 6. In VB 6, variables defined anywhere in a program can be used throughout the program. In VB.NET, variables defined in a subroutine can only be used in that subroutine (a subroutine is the code contained within these statements such as If...End If,For...Next,Select Case...End Select,Do...Loop. ).

This difference allows you to write code that is more stylized and flexible, while preventing variables from being called by programs that are supposed to be outside the scope of the VB.NET variable.

But there is a drawback to this change, which is that each variable keeps its value unchanged throughout the program. That is, when a variable is beyond its scope, its value is still stored in memory. If you enter the same subroutine again in the program, the previously stored value of this variable in memory may cause a potential error.

For instance. Take a look at the following code:

Dim x As Integer = 1 Dim holdY As Integer Do While (x < 5) If (x Mod 2 = 0) Then Dim y As Integer y + = 1 holdY = y End If x + = 1 Loop MsgBox (x) MsgBox (holdY)

After the above code runs, the value of x is 5 and the value of HoldY is 3. The application of the value of y is limited to the whole Do...Loop process.

Initializing a variable when defining a variable is a direct solution, it avoids any potential problems and ensures that the value of the variable is known each time it is used.

If (x Mod 2 = 0) Then Dim y As Integer = 0 y + = 1

Another benefit is that initializing variables in the definition makes the code more readable.

Thank you for reading this article carefully. I hope the article "sample Analysis of the scope of Application of VB.NET variables" shared by the editor will be helpful to you. At the same time, I also hope that you will support and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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