# ChangeHistoryService（ロブロックス クラス）

> **Must** be used by plugins to communicate to Studio how to undo and redo the changes which they make to the experience.

- URL：https://roblox.minecraft-okinawa.com/reference/classes/ChangeHistoryService/
- 公式：https://create.roblox.com/docs/reference/engine/classes/ChangeHistoryService
- 受け継いでいるクラス：Instance

## メソッド

- `ChangeHistoryService:FinishRecording(identifier: string, operation: FinishRecordingOperation, finalOptions: Dictionary?): ()`：Communicates to Studio that the identified recording is finished and to take the final operation to complete the recording.
- `ChangeHistoryService:GetCanRedo(): Tuple`：Returns whether there is an action available to redo and, if so, the name of that action.
- `ChangeHistoryService:GetCanUndo(): Tuple`：Returns whether there is an action available to undo and, if so, the name of that action.
- `ChangeHistoryService:IsRecordingInProgress(identifier: string?): boolean`：Returns whether the plugin currently has a recording in progress, optionally checking for a specific recording identifier.
- `ChangeHistoryService:Redo(): ()`：Re-executes the most recently undone action, advancing forward through the undo/redo history.
- `ChangeHistoryService:ResetWaypoints(): ()`：Clears the undo/redo history by collapsing it into a single base waypoint.
- `ChangeHistoryService:SetEnabled(state: boolean): ()`：Sets whether or not the ChangeHistoryService is enabled.
- `ChangeHistoryService:SetWaypoint(name: string): ()`：Sets a new waypoint which can be used as an undo or redo point.
- `ChangeHistoryService:TryBeginRecording(name: string, displayName: string?): string?`：Begins tracking changes made to the data model into a recording.
- `ChangeHistoryService:Undo(): ()`：Reverts the most recent action, stepping backward through the undo/redo history.

## イベント

- `ChangeHistoryService.OnRecordingFinished(name: string, displayName: string?, identifier: string?, operation: FinishRecordingOperation, finalOptions: Dictionary?)`：Fired when the user completes an action. Parameters come from Class.ChangeHistoryService:TryBeginRecording()|TryBeginRecording() and Class.ChangeHistoryService:FinishRecording()|FinishRecording().
- `ChangeHistoryService.OnRecordingStarted(name: string, displayName: string?)`：Fired when the user begins an action. Parameters come from Class.ChangeHistoryService:TryBeginRecording()|TryBeginRecording().
- `ChangeHistoryService.OnRedo(waypoint: string)`：Fires after an action is redone, reporting the name of the action that was replayed.
- `ChangeHistoryService.OnUndo(waypoint: string)`：Fires after an action is undone, reporting the name of the action that was reverted.

英語の説明とメンバー一覧：Roblox Creator Documentation（CC BY 4.0）。日本語の解説はこのサイト独自のものです。

執筆：鈴木孝昌（現役プロジェクトマネージャー／プログラミング講師）／運営：沖縄マイクラ部 プログラミングスクール「クロスウェーブ」（https://minecraft-okinawa.com/）