Static (Visual Basic)
Specifies that one or more declared local variables are to continue to exist and retain their latest values after termination of the procedure in which they are declared.
Remarks
Normally, a local variable in a procedure ceases to exist as soon as the procedure stops. A static variable continues to exist and retains its most recent value. The next time your code calls the procedure, the variable is not reinitialized, and it still holds the latest value that you assigned to it. A static variable continues to exist for the lifetime of the class or module that it is defined in.
Rules
Declaration Context. You can use Static only on local variables. This means the declaration context for a Static variable must be a procedure or a block in a procedure, and it cannot be a source file, namespace, class, structure, or module.
You cannot use Static inside a structure procedure.
The data types of Static local variables cannot be inferred. For more information, see Local Type Inference (Visual Basic).
Combined Modifiers. You cannot specify Static together with ReadOnly, Shadows, or Shared in the same declaration.
Behavior
When you declare a static variable in a Shared procedure, only one copy of the static variable is available for the whole application. You call a Shared procedure by using the class name, not a variable that points to an instance of the class.
When you declare a static variable in a procedure that isn't Shared, only one copy of the variable is available for each instance of the class. You call a non-shared procedure by using a variable that points to a specific instance of the class.
Example
The following example demonstrates the use of Static.
Function updateSales(ByVal thisSale As Decimal) As Decimal
Static totalSales As Decimal = 0
totalSales += thisSale
Return totalSales
End Function
The Static variable totalSales is initialized to 0 only one time. Each time that you enter updateSales, totalSales still has the most recent value that you calculated for it.
The Static modifier can be used in this context:
See Also
Reference
Concepts
Variable Declaration in Visual Basic
Local Type Inference (Visual Basic)
Other Resources
Objects and Classes in Visual Basic
Change History
Date |
History |
Reason |
|---|---|---|
|
March 2012 |
Clarified Shared procedures. |
Customer feedback. |