Class UndoContext

Gives access to a state based undo mechanism for ProjectObjects. Each Project has its own undo context. The undo context makes it possible to group changes to ProjectObjects. All changes in the group can then be undone and redone.

Inheritance

object

UndoContext

Namespace: ABB.Robotics.RobotStudio

Assembly: ABB.Robotics.RobotStudio.dll

Syntax

public sealed class UndoContext

Properties

CanRedo

Returns true if there are entries in the Redo queue, otherwise false.

Declaration

public bool CanRedo { get; }

Property Value

Type	Description
bool

CanUndo

Returns true if there are entries in the Undo queue, otherwise false.

Declaration

public bool CanUndo { get; }

Property Value

Type	Description
bool

CurrentUndoStepName

Gets or sets the name of the current undo step

Declaration

public string CurrentUndoStepName { get; set; }

Property Value

Type	Description
string

IsAppending

Returns true if the active undo step has been opened using AppendToUndoStep()

Declaration

public bool IsAppending { get; }

Property Value

Type	Description
bool

IsInUndoStep

Returns true if the application is currently inside an undo step.

Declaration

public bool IsInUndoStep { get; }

Property Value

Type	Description
bool

NumRedoSteps

Returns the number of available Redo steps

Declaration

public int NumRedoSteps { get; }

Property Value

Type	Description
int

NumUndoSteps

Returns the number of available Undo steps

Declaration

public int NumUndoSteps { get; }

Property Value

Type	Description
int

QueueSize

Gets or sets the maximum size for the Undo and Redo queues.

Declaration

public int QueueSize { get; set; }

Property Value

Type	Description
int

Methods

AddChange(IChange)

Adds an undoable operation (see IChange).

Declaration

public void AddChange(IChange change)

Parameters

Type	Name	Description
IChange	change

Remarks

If an undo step is not currently open, the change will be added to the previous undo step.

AppendToUndoStep(string)

Similar to BeginUndoStep(string), but tries to append changes to the previous undo step, instead of creating a new one.

Declaration

public void AppendToUndoStep(string name)

Parameters

Type	Name	Description
string	name

Remarks

The name must match the name of the previous undo step. Otherwise a new undo step one will be created.

AppendToUndoStep(string, bool)

Similar to BeginUndoStep(string), but tries to append changes to the previous undo step, instead of creating a new one.

Declaration

public void AppendToUndoStep(string name, bool forceAppend)

Parameters

Type	Name	Description
string	name	Name of undo step, if a new one is created.
bool	forceAppend	If true, changes are appended to the previous undostep (if one exists) even if the names do not match.

BeginUndoStep()

Starts a new unnamed undo step.

Declaration

public void BeginUndoStep()

Remarks

It is not recommended to make unnamed undo steps. Use BeginUndoStep(string name) instead.

BeginUndoStep(string)

Begins a new undo step.

Declaration

public void BeginUndoStep(string name)

Parameters

Type	Name	Description
string	name	The name of the undo step.

Remarks

The name should be localized, since it will be displayed in the user interface.

CancelUndoStep(CancelUndoStepType)

Marks the current undo step as canceled.

Declaration

public void CancelUndoStep(CancelUndoStepType cancelType)

Parameters

Type	Name	Description
CancelUndoStepType	cancelType

Remarks

When the canceled undo step is closed by EndUndoStep(), either all changes will be undone ("rollback"), or the undo/redo queues will be cleared, depending on the value of 'cancelType'.

Clear()

Clears the Undo and Redo queues.

Declaration

public void Clear()

EndUndoStep()

Ends the current undo step.

Declaration

public void EndUndoStep()

Remarks

It is legal to make nested calls to Begin/EndUndoStep(). Only the outermost EndUndoStep() call will actually close the undo step.

ExecuteAppendUndoStep(string, Action)

Creates or appends to an undo step and executes the code in the passed in delegate inside it.

Declaration

public bool ExecuteAppendUndoStep(string undoStepName, Action action)

Parameters

Type	Name	Description
string	undoStepName
Action	action

Returns

Type	Description
bool	True if the operation succeeded, false if an exception was thrown.

Remarks

The name must match the name of the previous undo step. Otherwise a new undo step one will be created. In case of an exception, the undo step will be rolled back and the error will be logged to the RobotStudio output window.

ExecuteUndoStep(string, Action)

Creates an undo step and executes the code in the passed in delegate inside it.

Declaration

public bool ExecuteUndoStep(string undoStepName, Action action)

Parameters

Type	Name	Description
string	undoStepName
Action	action

Returns

Type	Description
bool	True if the operation succeeded, false if an exception was thrown.

Remarks

In case of an exception, the undo step will be rolled back and the error will be logged to the RobotStudio output window.

ExecuteUndoStep(string, Action, Action<Exception>)

Creates an undo step and executes the code in the passed in delegate inside it.

Declaration

public bool ExecuteUndoStep(string undoStepName, Action action, Action<Exception> errorHandler)

Parameters

Type	Name	Description
string	undoStepName
Action	action
Action<Exception>	errorHandler

Returns

Type	Description
bool	True if the operation succeeded, false if an exception was thrown.

Remarks

In case of an exception, the passed in errorHandler delegate will be executed.

GetRedoNames()

Returns an array of the names of all redo steps in the redo queue

Declaration

public string[] GetRedoNames()

Returns

Type	Description
string[]

GetUndoNames()

Returns an array of the names of all undo steps in the undo queue

Declaration

public string[] GetUndoNames()

Returns

Type	Description
string[]

Redo()

Redoes the changes undone by the last call to Undo()

Declaration

public void Redo()

Remarks

It is not legal to call this method while inside an undo step.

ResumeUndoStep()

Resumes collection of undoable changes.

Declaration

public void ResumeUndoStep()

SuspendUndoStep()

Temporarily disables collection of undoable changes.

Declaration

public void SuspendUndoStep()

Undo()

Undoes the operations made during the last undo step.

Declaration

public void Undo()

Remarks

It is not legal to call this method while inside an undo step.

Events

Redoing

Occurs before a redo operation.

Declaration

public event EventHandler Redoing

Event Type

Type	Description
EventHandler

Redone

Occurs after a redo operation.

Declaration

public event EventHandler Redone

Event Type

Type	Description
EventHandler

Undoing

Occurs before an undo operation.

Declaration

public event EventHandler Undoing

Event Type

Type	Description
EventHandler

Undone

Occurs after an undo operation.

Declaration

public event EventHandler Undone

Event Type

Type	Description
EventHandler