Class PathNode

Basic shape node that contain collection of ControlPoint, segments, vertices to draw simple shapes.

Inheritance
System.Object
Node
PathNode
FilledPath
LineBase
Implements
System.Runtime.Serialization.ISerializable
System.ICloneable
System.IServiceProvider
System.Runtime.Serialization.IDeserializationCallback
System.IDisposable
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: Syncfusion.Windows.Forms.Diagram
Assembly: Syncfusion.Diagram.Base.dll
Syntax
public abstract class PathNode : Node, IUnitIndependent, IDispatchNodeEvents, ISerializable, INode, ICloneable, IServiceReferenceHolder, IServiceReferenceProvider, IPropertyObserver, IPropertyContainer, IServiceProvider, IGraphNode, IDeserializationCallback, IDisposable
Remarks

Used as base class for FilledPath and LineBase nodes.

Constructors

PathNode()

Initializes a new instance of the PathNode class.

Declaration
public PathNode()

PathNode(PathNode)

Initializes a new instance of the PathNode class.

Declaration
public PathNode(PathNode src)
Parameters
Type Name Description
PathNode src

The source instance.

PathNode(SerializationInfo, StreamingContext)

Initializes a new instance of the PathNode class.

Declaration
protected PathNode(SerializationInfo info, StreamingContext context)
Parameters
Type Name Description
System.Runtime.Serialization.SerializationInfo info

The serialization info.
System.Runtime.Serialization.StreamingContext context

The serialization context.

Fields

m_maxPoints

The maximum of path points.

Declaration
protected int m_maxPoints
Field Value
Type
System.Int32

m_minPoints

The minimum of path points.

Declaration
protected int m_minPoints
Field Value
Type
System.Int32

Properties

CanChangePath

Gets a value indicating whether this instance can change path.

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

true if this instance can change path; otherwise, false.

IsVertexEditable

Gets a value indicating whether this instance is vertex editable.

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

true if this instance is vertex editable; otherwise, false.

Labels

Gets the node collection of Label items.

Declaration
public LabelCollection Labels { get; }
Property Value
Type Description
LabelCollection

The collection of Label items.

LineSegmentCount

Gets the line segment count.

Declaration
public virtual int LineSegmentCount { get; }
Property Value
Type Description
System.Int32

The line segment count.
Remarks

Segment count equal to path point count for a closed path, and one less count for non-closed shape.

LogicalGraphicsPath

GraphicsPath containing points and instructions for rendering the shape.

Declaration
protected override GraphicsPath LogicalGraphicsPath { get; }
Property Value
Type
System.Drawing.Drawing2D.GraphicsPath
Overrides

MaxPoints

Gets or sets maximum number of vertices this shape may contain.

Declaration
public int MaxPoints { get; set; }
Property Value
Type
System.Int32

MinPoints

Gets or sets minimum number of vertices this shape may contain.

Declaration
public int MinPoints { get; set; }
Property Value
Type
System.Int32

PathPointsRelative

Gets or sets the internal relative path points cache.

Declaration
protected PointF[] PathPointsRelative { get; set; }
Property Value
Type Description
System.Drawing.PointF[]

The path points array.

PointCount

Gets number of vertices contained by the shape.

Declaration
public int PointCount { get; }
Property Value
Type
System.Int32

Methods

AccumulateRefreshRect(ref RectangleF)

Accumulates the refresh rectangle.

Declaration
protected override void AccumulateRefreshRect(ref RectangleF rcRefresh)
Parameters
Type Name Description
System.Drawing.RectangleF rcRefresh

The refresh rectangle.
Overrides

AddPoint(PointF)

Adds the point to the PathNode.

Declaration
public virtual void AddPoint(PointF val)
Parameters
Type Name Description
System.Drawing.PointF val

The System.Drawing.PointF to add to the PathNode in local coordinates.

AddPoint(PointF, Boolean)

Adds the point to the PathNode.

Declaration
public void AddPoint(PointF val, bool bInLocal)
Parameters
Type Name Description
System.Drawing.PointF val

The System.Drawing.PointF to add to the PathNode.
System.Boolean bInLocal

Set to true if given point in local coordinates, otherwise - false.

BeforeMoveSegment(ref PointF[])

Helper method used to perform additional actions before updating path node data. Used by Connectors to merge control points.

Declaration
protected virtual void BeforeMoveSegment(ref PointF[] ptsNew)
Parameters
Type Name Description
System.Drawing.PointF[] ptsNew

The new path points.

CanChangePoints(PointF[])

Determines whether this points can locate in current model.

Declaration
protected virtual bool CanChangePoints(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The points.
Returns
Type Description
System.Boolean

true if this points can locate in model; otherwise, false.

CanCombine(GraphicsPath)

Determines whether this instance can combine the specified path to combine with.

Declaration
public bool CanCombine(GraphicsPath pathToCombineWith)
Parameters
Type Name Description
System.Drawing.Drawing2D.GraphicsPath pathToCombineWith

The path to combine with.
Returns
Type Description
System.Boolean

true if this instance can combine the specified path to combine with; otherwise, false.

CanDrawControlPoints()

Determines whether this node can draw control points.

Declaration
public virtual bool CanDrawControlPoints()
Returns
Type Description
System.Boolean

true if this node can draw control points; otherwise, false.

CanEditControlPoint()

Determines whether this node can edit control points.

Declaration
public virtual bool CanEditControlPoint()
Returns
Type Description
System.Boolean

true if this node can edit control points; otherwise, false.

CanEditSegment()

Determines whether this node can edit segments.

Declaration
public virtual bool CanEditSegment()
Returns
Type Description
System.Boolean

true if this node can edit segments; otherwise, false.

CanEditVertexPoint()

Determines whether this node can edit vertex points.

Declaration
public virtual bool CanEditVertexPoint()
Returns
Type Description
System.Boolean

true if this node can edit vertex point; otherwise, false.

CanMoveHandle(IHandle)

Determines whether this node allow move it handle.

Declaration
public bool CanMoveHandle(IHandle handle)
Parameters
Type Name Description
IHandle handle

The handle to move.
Returns
Type Description
System.Boolean

true if this node allow move it handle; otherwise, false.

CanMoveHandle(IHandle, PointF)

Determines whether this node allow move it handle.

Declaration
public virtual bool CanMoveHandle(IHandle handle, PointF ptNewLocation)
Parameters
Type Name Description
IHandle handle

The handle to move.
System.Drawing.PointF ptNewLocation

The new endpoint location to check.
Returns
Type Description
System.Boolean

true if this node allow move it handle; otherwise, false.

ContainsHandle(IHandle)

Determines whether the node contains specific handle.

Declaration
public virtual bool ContainsHandle(IHandle handle)
Parameters
Type Name Description
IHandle handle

The handle.
Returns
Type Description
System.Boolean

true if the handle contains specific handle; otherwise, false.

CreateGraphicsPath(PointF[])

Creates the graphics path from path points.

Declaration
protected GraphicsPath CreateGraphicsPath(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The path points array.
Returns
Type Description
System.Drawing.Drawing2D.GraphicsPath

Graphics path

CreateLogicalGraphicsPath(PointF[])

Creates node's path with given array of points.

Declaration
protected virtual GraphicsPath CreateLogicalGraphicsPath(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

Points to create path from.
Returns
Type Description
System.Drawing.Drawing2D.GraphicsPath

Created GraphicsPath, otherwise null.

Dispose()

Declaration
public override void Dispose()
Overrides

DoHandleMoveRelated(IHandle, SizeF)

Does the handle move related.

Declaration
protected virtual void DoHandleMoveRelated(IHandle handleMoved, SizeF szOffset)
Parameters
Type Name Description
IHandle handleMoved

The handle moved.
System.Drawing.SizeF szOffset

The move offset.

DoSizeRelatedActions(SizeF, SizeF)

Performs additional changes on size value changed.

Declaration
protected override void DoSizeRelatedActions(SizeF szOldSize, SizeF szNewSize)
Parameters
Type Name Description
System.Drawing.SizeF szOldSize

Old size value.
System.Drawing.SizeF szNewSize

New size value.
Overrides

DrawControlPoint(Graphics, ControlPoint, SizeF, Pen, Brush)

Draw the control point on graphics.

Declaration
public virtual void DrawControlPoint(Graphics gfx, ControlPoint ctrlPoint, SizeF szHandleSize, Pen penHandleOutline, Brush brushHandle)
Parameters
Type Name Description
System.Drawing.Graphics gfx

Graphics to draw on.
ControlPoint ctrlPoint

The control point.
System.Drawing.SizeF szHandleSize

Size of the handle.
System.Drawing.Pen penHandleOutline

The pen handle outline.
System.Drawing.Brush brushHandle

The fill brush handle.

DrawControlPoints(Graphics)

Draws the control points.

Declaration
public virtual void DrawControlPoints(Graphics gfx)
Parameters
Type Name Description
System.Drawing.Graphics gfx

Graphics to draw on.

FinishSetPoints()

Finishes the set points operation.

Declaration
protected virtual void FinishSetPoints()

GetAdjacentPathPoint(PointF, Boolean, Boolean, out PointF)

Searches for adjacent point from points that forms pathnode's path.

Declaration
public bool GetAdjacentPathPoint(PointF ptPathPoint, bool bInLocalCoordinates, bool bLeftHand, out PointF ptAdjacentPoint)
Parameters
Type Name Description
System.Drawing.PointF ptPathPoint

Point to search adjacent point to.
System.Boolean bInLocalCoordinates

Indicates whether adjacent point is in local coordinates.
System.Boolean bLeftHand

Indicates whether adjacent point is previous or next to given point.
System.Drawing.PointF ptAdjacentPoint

Adjacent point.
Returns
Type Description
System.Boolean

Value indicating whether search was successful.

GetControlPointAt(PointF)

Gets the control point at position.

Declaration
public ControlPoint GetControlPointAt(PointF ptTesting)
Parameters
Type Name Description
System.Drawing.PointF ptTesting

The given point.
Returns
Type Description
ControlPoint

Control point at the specified point.

GetControlPointAt(Int32)

Gets the control point by list index.

Declaration
public ControlPoint GetControlPointAt(int nIndex)
Parameters
Type Name Description
System.Int32 nIndex

Point list index.
Returns
Type Description
ControlPoint

Control point at the specified index.

GetControlPointByID(Int32)

Gets the control point by ID.

Declaration
public ControlPoint GetControlPointByID(int nID)
Parameters
Type Name Description
System.Int32 nID

The control point unique ID.
Returns
Type Description
ControlPoint

The ControlPoint.

GetControlPoints()

Gets the array of control points.

Declaration
public ControlPoint[] GetControlPoints()
Returns
Type Description
ControlPoint[]

Control points array.

GetLineSegmentAtPoint(PointF)

Gets the line segment at point it local coordinates.

Declaration
public virtual int GetLineSegmentAtPoint(PointF ptTesting)
Parameters
Type Name Description
System.Drawing.PointF ptTesting

The point testing.
Returns
Type Description
System.Int32

return the value for the Line segment.

GetLineSegmentPoints(Int32)

Gets the segment points.

Declaration
public virtual PointF[] GetLineSegmentPoints(int segmentIndex)
Parameters
Type Name Description
System.Int32 segmentIndex

Index of the segment.
Returns
Type Description
System.Drawing.PointF[]

One-dimension array with two elements where first element is start point and second is end point.

GetNewBounds(PointF[])

Gets the new bounds.

Declaration
protected RectangleF GetNewBounds(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The array of points.
Returns
Type Description
System.Drawing.RectangleF

The node bounds.

GetNewPathBounds(PointF[])

Gets the new path points bounds.

Declaration
protected virtual RectangleF GetNewPathBounds(PointF[] pathPoints)
Parameters
Type Name Description
System.Drawing.PointF[] pathPoints

The path points.
Returns
Type Description
System.Drawing.RectangleF

The System.Drawing.RectangleF.

GetObjectData(SerializationInfo, StreamingContext)

Populates a System.Runtime.Serialization.SerializationInfo with the data needed to serialize the target object.

Declaration
protected override void GetObjectData(SerializationInfo info, StreamingContext context)
Parameters
Type Name Description
System.Runtime.Serialization.SerializationInfo info

The System.Runtime.Serialization.SerializationInfo to populate with data.
System.Runtime.Serialization.StreamingContext context

The destination (see System.Runtime.Serialization.StreamingContext) for this serialization.
Overrides
Exceptions
Type Condition
System.Security.SecurityException

The caller does not have the required permission.

GetPathPoints()

Gets array of points needed to construct node's GraphicsPath.

Declaration
protected virtual PointF[] GetPathPoints()
Returns
Type Description
System.Drawing.PointF[]

Array of path points

GetPathPoints(Matrix)

Gets the transformed path points.

Declaration
protected PointF[] GetPathPoints(Matrix mtxTransform)
Parameters
Type Name Description
System.Drawing.Drawing2D.Matrix mtxTransform

Matrix transformations.
Returns
Type Description
System.Drawing.PointF[]

Array of transformed path points.

GetPoint(Int32)

Gets the vertex point in local coordinates.

Declaration
public virtual PointF GetPoint(int ptIdx)
Parameters
Type Name Description
System.Int32 ptIdx

The vertex index.
Returns
Type Description
System.Drawing.PointF

The System.Drawing.PointF.

GetPoint(Int32, Boolean)

Gets the vertex point in local coordinates. Set the boolean parameter to True to get the Graphical path for line connector.

Declaration
public virtual PointF GetPoint(int ptIdx, bool bReturnGraphical)
Parameters
Type Name Description
System.Int32 ptIdx

The vertex index.
System.Boolean bReturnGraphical

Determines whether the points should be relative to grpah.
Returns
Type Description
System.Drawing.PointF

The System.Drawing.PointF.

GetPoints()

Returns an array containing all vertices belonging to this shape.

Declaration
public virtual PointF[] GetPoints()
Returns
Type Description
System.Drawing.PointF[]

Array of points in local coordinates.

GetPoints(Boolean)

Returns an array containing all vertices belonging to this shape.

Declaration
public virtual PointF[] GetPoints(bool bInLocal)
Parameters
Type Name Description
System.Boolean bInLocal

Set to true to get points in local coordinates, otherwise - false.
Returns
Type Description
System.Drawing.PointF[]

The System.Drawing.PointF.

HandleMove(IHandle, SizeF)

Handles the move.

Declaration
protected void HandleMove(IHandle handleMoved, SizeF szOffset)
Parameters
Type Name Description
IHandle handleMoved

The moving handle.
System.Drawing.SizeF szOffset

Handle move offset.

InsertPoint(Int32, PointF)

Inserts the point to the PathNode at the specified index.

Declaration
public virtual void InsertPoint(int ptIdx, PointF val)
Parameters
Type Name Description
System.Int32 ptIdx

The zero-based index ar which ptIdx should be inserted.
System.Drawing.PointF val

The point in local coordinates.

InsertPoint(Int32, PointF, Boolean)

Inserts the point to the PathNode at the specified index.

Declaration
public void InsertPoint(int ptIdx, PointF val, bool bInLocal)
Parameters
Type Name Description
System.Int32 ptIdx

The zero-based index ar which ptIdx should be inserted.
System.Drawing.PointF val

The point to insert.
System.Boolean bInLocal

Set to true if given point in local coordinates, otherwise - false.

IsControlPointValid(ControlPoint)

Determines whether given control point is valid.

Declaration
public bool IsControlPointValid(ControlPoint ctrlPtValidating)
Parameters
Type Name Description
ControlPoint ctrlPtValidating

The control point to validating.
Returns
Type Description
System.Boolean

true if given control point is valid; otherwise, false.

IsPathVertexEditable(GraphicsPath)

Checks whether VertexEditMode can be applied to current PathNode.

Declaration
protected bool IsPathVertexEditable(GraphicsPath path)
Parameters
Type Name Description
System.Drawing.Drawing2D.GraphicsPath path

The path.
Returns
Type Description
System.Boolean

true if specified path is vertex editable; otherwise, false.

MoveLineSegment(Int32, SizeF)

Moves the line segment.

Declaration
public bool MoveLineSegment(int lineSegmentIndex, SizeF szOffset)
Parameters
Type Name Description
System.Int32 lineSegmentIndex

Index of the line segment.
System.Drawing.SizeF szOffset

The size offset.
Returns
Type Description
System.Boolean

If move operation is succeed.

MoveSegment(Int32, SizeF)

Moves the segment to given offset.

Declaration
protected virtual PointF[] MoveSegment(int lineSegmentIndex, SizeF szOffset)
Parameters
Type Name Description
System.Int32 lineSegmentIndex

Index of the line segment.
System.Drawing.SizeF szOffset

The segment move offset.
Returns
Type Description
System.Drawing.PointF[]

The points to offset.

OnDeserialized()

Called when node is deserialized.

Declaration
protected override void OnDeserialized()
Overrides

OnMouseEnter(EventArgs)

Raises the mouse enter event.

Declaration
protected override void OnMouseEnter(EventArgs e)
Parameters
Type Name Description
System.EventArgs e
Overrides

OnMouseLeave(EventArgs)

Raises the mouse leave event.

Declaration
protected override void OnMouseLeave(EventArgs e)
Parameters
Type Name Description
System.EventArgs e
Overrides

OnNodeScaleChanged(String)

Called when node scale factor is changed.

Declaration
protected override void OnNodeScaleChanged(string strPropertyName)
Parameters
Type Name Description
System.String strPropertyName

The property name that change scale factor value.
Overrides

OnVertexChanged(VertexChangeType, Int32, PointF)

Called when vertex change.

Declaration
public virtual void OnVertexChanged(VertexChangeType changeType, int nVertexIdx, PointF ptLocation)
Parameters
Type Name Description
VertexChangeType changeType

Type of collection change.
System.Int32 nVertexIdx

The vertex index.
System.Drawing.PointF ptLocation

The given point.

OnVertexChanging(VertexChangeType, Int32, PointF)

Called when vertex changing.

Declaration
public virtual bool OnVertexChanging(VertexChangeType changeType, int nVertexIdx, PointF ptLocation)
Parameters
Type Name Description
VertexChangeType changeType

Type of vertex the change.
System.Int32 nVertexIdx

The vertex id.
System.Drawing.PointF ptLocation

The point location.
Returns
Type Description
System.Boolean

true, if vertex is changing.

PreparePathPointsForInsert(Int32, PointF)

Prepares new path points

Declaration
protected virtual PointF[] PreparePathPointsForInsert(int ptIdx, PointF val)
Parameters
Type Name Description
System.Int32 ptIdx

The point index.
System.Drawing.PointF val

The point.
Returns
Type Description
System.Drawing.PointF[]

The new path points.
Remarks

You should override this method if custom login needed (e.g. - if You are inserting point into orthogonal line -> two points must be inserted!)

RecordVertexChanged(VertexChangeType, Int32, PointF)

Records the vertex changed.

Declaration
protected void RecordVertexChanged(VertexChangeType changeType, int nVertexIdx, PointF ptVertexNewLocation)
Parameters
Type Name Description
VertexChangeType changeType

Type of collection change.
System.Int32 nVertexIdx

The vertex index.
System.Drawing.PointF ptVertexNewLocation

The vertex new location.

RemovePoint(Int32)

Removes the path point by it id.

Declaration
public virtual void RemovePoint(int ptIdx)
Parameters
Type Name Description
System.Int32 ptIdx

The vertex index.

RenderContiguousData(Graphics)

The methods used to draw contiguous date. Such as labels or ports.

Declaration
protected override void RenderContiguousData(Graphics gfx)
Parameters
Type Name Description
System.Drawing.Graphics gfx

Graphics to draw on
Overrides

SetControlPoints(PointF[], Int32)

Set the control points location.

Declaration
protected virtual void SetControlPoints(PointF[] ptsPath, int nStartIndex)
Parameters
Type Name Description
System.Drawing.PointF[] ptsPath

The points path.
System.Int32 nStartIndex

Index of the beginning control path points.

SetPoint(Int32, PointF)

Sets the point new value.

Declaration
public virtual void SetPoint(int ptIdx, PointF val)
Parameters
Type Name Description
System.Int32 ptIdx

The vertex index.
System.Drawing.PointF val

The new value point in local coordinates.

SetPoint(Int32, PointF, Boolean)

Sets the point new value.

Declaration
public void SetPoint(int ptIdx, PointF val, bool bInLocal)
Parameters
Type Name Description
System.Int32 ptIdx

The vertex index.
System.Drawing.PointF val

The point to set.
System.Boolean bInLocal

Set to true if given point in local coordinates, otherwise - false.

SetPoints(PointF[])

Sets the new points in local coordinates.

Declaration
public void SetPoints(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The local points.

SetPoints(PointF[], Boolean)

Sets the new points.

Declaration
public void SetPoints(PointF[] pts, bool bInLocal)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The points to set.
System.Boolean bInLocal

Set to true if given points in local coordinates, otherwise - false.

TransformControlPoints(Matrix)

Transforms the node control points.

Declaration
protected void TransformControlPoints(Matrix mtxTransform)
Parameters
Type Name Description
System.Drawing.Drawing2D.Matrix mtxTransform

Matrix transformations.

TryCombine(GraphicsPath, Boolean)

Tries to combine given graphics path with current.

Declaration
public bool TryCombine(GraphicsPath pathToCombineWith, bool bConnect)
Parameters
Type Name Description
System.Drawing.Drawing2D.GraphicsPath pathToCombineWith

The path to combine with.
System.Boolean bConnect

if set to true connect.
Returns
Type Description
System.Boolean

If path's combined successfully - true, otherwise - false
Remarks

All combining path pathPoints must be in GraphicsUnit.Pixel.

UpdateBoundsInfo(RectangleF)

Updates the bounds info.

Declaration
protected virtual void UpdateBoundsInfo(RectangleF rcBounds)
Parameters
Type Name Description
System.Drawing.RectangleF rcBounds

The bounds rectangle.

UpdateControlPoints(PointF[], Int32)

Update the control points using given path points.

Declaration
protected void UpdateControlPoints(PointF[] ptsPath, int nStartIndex)
Parameters
Type Name Description
System.Drawing.PointF[] ptsPath

The array of points.
System.Int32 nStartIndex

Index of the beginning control path points.

UpdateGraphicsPath(PointF[])

Updates node's GraphicsPath on given array of points.

Declaration
protected virtual void UpdateGraphicsPath(PointF[] pts)
Parameters
Type Name Description
System.Drawing.PointF[] pts

The new path points array.

UpdateNonLineBoundsInfo(RectangleF)

Updates the non line bounds info.

Declaration
protected void UpdateNonLineBoundsInfo(RectangleF rcBounds)
Parameters
Type Name Description
System.Drawing.RectangleF rcBounds

The bounds rectangle.

UpdatePathLocation(ref GraphicsPath, RectangleF)

Updates the path location.

Declaration
protected void UpdatePathLocation(ref GraphicsPath pathCombined, RectangleF rect)
Parameters
Type Name Description
System.Drawing.Drawing2D.GraphicsPath pathCombined

The combined path .
System.Drawing.RectangleF rect

The rectangle to combine.

UpdatePathNodeData()

Updates the graphics path.

Declaration
protected void UpdatePathNodeData()

UpdateReferences(IServiceReferenceProvider)

Updates the references from service provider.

Declaration
public override void UpdateReferences(IServiceReferenceProvider provider)
Parameters
Type Name Description
IServiceReferenceProvider provider

The service provider.
Overrides

UpdateSegmentsRegion()

Updates the segments region cache.

Declaration
protected void UpdateSegmentsRegion()
Remarks

Create region segment cache and save to m_cacheRegionsSegment.

ValidateOffset(Int32, ref SizeF)

Validates the offset.

Declaration
protected virtual void ValidateOffset(int lineSegmentIndex, ref SizeF szOffset)
Parameters
Type Name Description
System.Int32 lineSegmentIndex

Index of the line segment.
System.Drawing.SizeF szOffset

The move offset.

Implements

System.Runtime.Serialization.ISerializable
System.ICloneable
System.IServiceProvider
System.Runtime.Serialization.IDeserializationCallback
System.IDisposable