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API > API/Runtime > API/Runtime/Core > API/Runtime/Core/Misc
Inheritance Hierarchy
References
| Module | Core |
| Header | /Engine/Source/Runtime/Core/Public/Misc/Change.h |
| Include | #include "Misc/Change.h" |
Syntax
class FChange
Remarks
FChange modifies a UObject and is meant to be used to implement undo/redo. The change is embedded in an FTransaction which executes it instead of the standard serialization transaction (cannot be combined - see FTransaction).
The original FChange style (used by MeshEditor) was that calling Execute() would return a new FChange that applies the opposite action, and FTransaction would swap the two at each undo/redo step (eg a "DeleteObject" FChange would return a "CreateObject" FChange)
The alternative "Command Pattern"-style FChange calls Apply() and Revert() on a single FChange.
FChange may eventually be deprecated. You should subclass FSwapChange and FCommandChange to implement these different styles.
Constructors
| Type | Name | Description | |
|---|---|---|---|
 |
FChange () |
Protected default constructor |
Destructors
| Type | Name | Description | |
|---|---|---|---|
  |
~FChange () |
Virtual destructor |
Functions
| Type | Name | Description | |
|---|---|---|---|
  |
void | AddReferencedObjects
(
FReferenceCollector& Collector |
Used by GC to collect referenced objects. |
 |
void | Apply
(
UObject* Object |
Makes the change to the object |
 |
TUniquePtr< FChange > | Execute
(
UObject* Object |
Makes the change to the object, returning a new change that can be used to perfectly roll back this change |
 |
EChangeStyle | What style of change is this | |
   |
bool | HasExpired
(
UObject* Object |
|
  |
void | PrintToLog
(
FFeedbackContext& FeedbackContext, |
Prints this change to the log, including sub-changes if there are any. |
 |
void | Revert
(
UObject* Object |
Reverts change to the object |
  |
FString | ToString () |
Describes this change (for debugging) |
Enums
| Type | Name | Description | |
|---|---|---|---|
 |
EChangeStyle |