Invoke( ) method (Class)

Dynamically invokes a method whose name and parameters must be set at run time. The Invoke( ) method is one of several reflection methods of the Progress.Lang.Class class that provide type information about a class or interface at run time.

Return type:

Any data type

Access:

PUBLIC

Applies to:

Progress.Lang.Class class

Four overloaded versions are supported. The first version is used to invoke a method that does not take any parameters.

 

Syntax 

[ return-value = ] class-reference:Invoke (   INPUT object-reference AS Progress.Lang.Object ,   INPUT method-name AS CHARACTER )

The second overloaded version is used to invoke a method that takes zero or more parameters. Since parameterlist-object can be built with zero or more parameters, this version of the Invoke( ) method can be used to invoke any method, even those that do not take any arguments.

 

Syntax 

[ return-value = ] class-reference:Invoke (   INPUT object-reference AS Progress.Lang.Object ,   INPUT method-name AS CHARACTER ,   INPUT parameterlist-object AS Progress.Lang.ParameterList )

The third overloaded version is used when invoking a static method that does not take any parameters.

 

Syntax 

[ return-value = ] class-reference:Invoke ( INPUT method-name AS CHARACTER )

The fourth overloaded version is used when invoking a static method that takes zero or more parameters. Since parameterlist-object can be built with zero or more parameters, this version of the Invoke( ) method can be used to invoke any static method, even those that do not take any arguments.

 

Syntax 

[ return-value = ] class-reference:Invoke (   INPUT method-name AS CHARACTER ,   INPUT parameterlist-object AS Progress.Lang.ParameterList )

Element descriptions for the syntax diagrams follow:

return-value

An optional data element which is assigned the return value from the invoked, non-void method. This return value can have any valid ABL or .NET method return type. The AVM checks return-value at run time for data type compatibility with what is actually returned by the method.

class-reference

An object reference to the Progress.Lang.Class class instance containing the type information.

object-reference

A reference to the object that contains the method you want to invoke, and whose type is compatible with the class-reference object. When invoking a static method, the Unknown value (?) is passed for this parameter.

method-name

A CHARACTER expression that evaluates at run time to the name of the method to be invoked.

parameterlist-object

An instance of the Progress.Lang.ParameterList class.

Notes:

The DYNAMIC-INVOKE function provides similar functionality to the Invoke( ) method. The advantage of the former is that it has a fixed, compile-time parameter list and does not require the creation of a Progress.Lang.ParameterList object at run time.

See also:

DYNAMIC-INVOKE function, DYNAMIC-NEW statement, New( ) method, NumParameters property, Progress.Lang.ParameterList class, SetParameter( ) method (Class)