UKismetSystemLibrary::BeginTransaction

function Engine Blueprint Since unknown

#include "Kismet/KismetSystemLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Begins a new undo transaction, defined as all actions that take place when the user selects 'Undo' once. Editor-only.

Caveats & Gotchas

• If a transaction is already in progress, this increments its action counter instead of starting a new one — always pair each BeginTransaction with a matching EndTransaction or CancelTransaction.
• You must call TransactObject for each object you're about to modify so it's captured in the undo buffer; BeginTransaction alone doesn't record anything.
• Only available in the editor — this has no effect (and no undo history) in packaged games.
• Returns -1 on failure, and a value greater than 0 if a transaction was already active; only rely on the return value to detect nesting, not for control flow.

Signature

static int32 BeginTransaction(const FString& Context, FText Description, UObject* PrimaryObject)

Parameters

Name	Type	Description	Default
Context	FString	The context for the undo session, typically the tool/editor that caused the operation.	—
Description	FText	The description shown next to the Undo item in the Edit menu.	—
PrimaryObject	UObject*	The primary object the undo session operates on. Can be null, and usually is.	—

Return Type

int32

Example

Wrap a scripted edit in an undoable transaction C++

UKismetSystemLibrary::BeginTransaction(TEXT("MyEditorTool"), FText::FromString(TEXT("Adjust Health Values")), nullptr);
UKismetSystemLibrary::TransactObject(TargetActor);
// ... modify TargetActor ...
UKismetSystemLibrary::EndTransaction();

Version History

Introduced in: unknown

Version	Status	Notes
5.6	stable	—

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