AINSTANCE( ) Function
Places instances of a class into a variable array and returns the number of instances placed in the array.
AINSTANCE(ArrayName, cClassName)
Numeric
ArrayName
Specifies the name of the array into which the instances are placed. If the array you specify doesn't exist, Visual FoxPro automatically creates the array. If the array exists and isn't large enough to contain all the instances, Visual FoxPro automatically increases the size of the array to accommodate the instances. If the array is larger than necessary, Visual FoxPro truncates the array. If the array exists and AINSTANCE( ) returns 0 because no instances are found, the array remains unchanged. If the array doesn't exist and AINSTANCE( ) returns 0, the array is not created.Only class instances assigned to variables and array elements with CREATEOBJECT( ) or NEWOBJECT( ) are placed into the array.
cClassName
Specifies a Visual FoxPro base class name or a user-defined class name. The following table lists the Visual FoxPro base classes you can specify for cClassName:Base Class Names CheckBox Line Column ListBox ComboBox OLEControl CommandButton OLEBoundControl CommandGroup OptionButton Container OptionGroup Control Page Cursor PageFrame Custom ProjectHook DataEnvironment Relation EditBox Separator Form Session FormSet Shape Grid Spinner Header TextBox Hyperlink Timer Image ToolBar
In the following example, CREATEOBJECT( ) is used to create two instances of the Visual FoxPro Form base class. AINSTANCE( ) is used to create an array named gaMyArray
that contains the variable references (goINSTANCE1
and goINSTANCE2
) for each form instance. The contents of the array are then displayed.
CLEAR ALL
goINSTANCE1 = CREATEOBJECT('Form')
goINSTANCE2 = CREATEOBJECT('Form')
CLEAR
? AINSTANCE(gaMyArray, 'Form') && Returns 2, two form instances
DISPLAY MEMORY LIKE gaMyArray && Displays the references
ADD CLASS COMMAND | AMEMBERS( ) Function | CREATE CLASS COMMAND | CREATE CLASSLIB COMMAND | CREATEOBJECT( ) FUNCTION | DEFINE CLASS COMMAND