Class HistoryManager

This class allows the user to simply implement Undo\Redo engine. To achieve this, class that supports Undo\Redo must implement ISuppportHistory interface and ICommand interface, which will actually execute specified actions for each undo\redo step. HistoryManager supports executing more undo\redo actions as one block. Use BeginBlock(), CloseBlock() for this.

Inheritance
System.Object
HistoryManager
HistoryManager
Implements
Inherited Members
System.Object.ToString()
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
Namespace: Syncfusion.Windows.Forms
Assembly: Syncfusion.Tools.Windows.dll
Syntax
public class HistoryManager : IHistoryManager

Constructors

HistoryManager()

Initializes a new instance of the HistoryManager class.

Declaration
public HistoryManager()

Properties

CanRedo

Gets a value indicating whether Redo Command list is not empty. Returns true if not empty; false otherwise.

Declaration
public bool CanRedo { get; }
Property Value
Type Description
System.Boolean

CanUndo

Gets a value indicating whether Undo Commands list is not empty. Returns true if not empty; false otherwise.

Declaration
public bool CanUndo { get; }
Property Value
Type Description
System.Boolean

IsBlockOpened

Gets a value indicating whether the block of commands is opened.

Declaration
protected bool IsBlockOpened { get; }
Property Value
Type Description
System.Boolean

Methods

BeginBlock()

Begins block of commands. User may add more than one command to Undo\Redo list and unite them into one command, e.g. : Each Opened block must be closed. Block of commands may be opened multiple times, but IT MUST BE CLOSED that many times as it was opened.

Declaration
public void BeginBlock()
Remarks
BeginBlock();
// add action1
// .....
BeginBlock();
//......
EndBlock();
// add actionN
CloseBlock();

CloseBlock()

Closes block of commands.

Declaration
public void CloseBlock()
Remarks

See BeginBlock() for more details.

Do(ICommand)

Adds command to history list.

Declaration
public void Do(ICommand cmd)
Parameters
Type Name Description
ICommand cmd

Command to add.

Redo()

Performs Redo operation.

Declaration
public bool Redo()
Returns
Type Description
System.Boolean

True if successful; false otherwise.

Reset()

Resets history.

Declaration
public void Reset()

ResetRedoStack()

Resets the Redo Stack

Declaration
public void ResetRedoStack()

ResetUndoStack()

Resets the Undo Stack

Declaration
public void ResetUndoStack()

RollBack()

Rolls back non-closed block.

Declaration
public void RollBack()

Undo()

Performs UnDo operation.

Declaration
public bool Undo()
Returns
Type Description
System.Boolean

True if successful; false otherwise.

Implements