RAD Studio VCL Reference
EInvalidOperation Class

EInvalidOperation is the exception class for invalid operations on a component.

EInvalidOperation = class(Exception);
class EInvalidOperation : public Exception;

EInvalidOperation is raised when an application attempts an operation that requires a window or widget handle on a component that does not have a parent (The Parent property is Nil in Delphi or NULL in C++). This exception can also occur if a drag-and-drop operation is attempted from a form (for example, when calling the BeginDrag method of a form).

Note: Do not confuse this object with EInvalidOp.

Copyright(C) 2009 Embarcadero Technologies, Inc. All Rights Reserved.
What do you think about this topic? Send feedback!