#VISUAL BASIC DATA STRUCTURE CODE#

The contents of local arrays can also be preserved while the program is still running. Add a second command button, which will add a new Click procedure, and try amending or printing the value of the static variable. Note: The new static variable is still local in scope, if any other procedure tries to access this variable it will be unable to do so. Thus, we can now see a list of numbers being incremented by 1 every time the command button is clicked. This time instead of the local variable being destroyed when the procedure terminates its value remains until the whole program ends. Static number As Integer ' Create a static local variable To stop this happening enter the keyword Static instead of Dim: Private Sub Command1_Click () It has exactly the same name in the program but it is a completely different variable. This is because each time the procedure is called, by clicking on the command button, VB is working with a different variable. The value never gets above 1 even though 1 is added to the variable each time.

#VISUAL BASIC DATA STRUCTURE CODE#

Add the following code to a command button and see what values are printed: Private Sub Command1_Click ()ĭim number As Integer ' Create a normal local variableĪfter clicking on the command button a few times you should see a whole column of 1s down the left hand side of the form. However, when using a local variable in a procedure VB creates memory space to hold the variables contents when it reads the Dim statement, but when it gets to the end of the procedure ( End Sub) it frees the space allocated to the local variable. Public - Can be accessed in any procedure in any module (use Public within the Declarations section of a module).ĭeclaring variables and arrays ( see below) as local to the current procedure/function is useful because it minimises strange side-effects which can occur with public variables.

Module - Variable can only be accessed in any procedure in the current form of module (use Private within the Declarations section on a form or module).Local - Variable can only be used in the current procedure (use Dim within the required procedure).The scope of a variable is defined as its operating range. The first example assigns a constant to a variable, while the second assigns the contents of another variable multiplied by ten. Once a new variable has been created a value can be assigned to it for storage. If a new variable is declared without specifying a type then by default it will be

Visual basic data structure