Class HexView

An hex viewer and editor View over a Stream
Inheritance
object
Responder
View
HexView
Implements
Inherited Members
Namespace: Terminal.Gui
Assembly: Terminal.Gui.dll
Syntax
public class HexView : View, IDisposable, ISupportInitializeNotification, ISupportInitialize
Remarks

HexView provides a hex editor on top of a seekable Stream with the left side showing an hex dump of the values in the Stream and the right side showing the contents (filtered to non-control sequence ASCII characters).

Users can switch from one side to the other by using the tab key.

To enable editing, set AllowEdits to true. When AllowEdits is true the user can make changes to the hexadecimal values of the Stream. Any changes are tracked in the Edits property (a SortedDictionary<TKey, TValue>) indicating the position where the changes were made and the new values. A convenience method, ApplyEdits(Stream) will apply the edits to the Stream.

Control the first byte shown by setting the DisplayStart property to an offset in the stream.

Constructors

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HexView()

Initializes a HexView class using Computed layout.
Declaration
public HexView()
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HexView(Stream)

Initializes a HexView class using Computed layout.
Declaration
public HexView(Stream source)
Parameters
Type Name Description
Stream source The Stream to view and edit as hex, this Stream must support seeking, or an exception will be thrown.

Properties

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AllowEdits

Gets or sets whether this HexView allow editing of the Stream of the underlying Stream.
Declaration
public bool AllowEdits { get; set; }
Property Value
Type Description
bool true if allow edits; otherwise, false.
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BytesPerLine

The bytes length per line.
Declaration
public int BytesPerLine { get; }
Property Value
Type Description
int
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CursorPosition

Gets the current cursor position starting at one for both, line and column.
Declaration
public Point CursorPosition { get; }
Property Value
Type Description
Point
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DesiredCursorVisibility

Get / Set the wished cursor when the field is focused
Declaration
public CursorVisibility DesiredCursorVisibility { get; set; }
Property Value
Type Description
CursorVisibility
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DisplayStart

Sets or gets the offset into the Stream that will displayed at the top of the HexView
Declaration
public long DisplayStart { get; set; }
Property Value
Type Description
long The display start.
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Edits

Gets a SortedDictionary<TKey, TValue> describing the edits done to the HexView. Each Key indicates an offset where an edit was made and the Value is the changed byte.
Declaration
public IReadOnlyDictionary<long, byte> Edits { get; }
Property Value
Type Description
IReadOnlyDictionary<long, byte> The edits.
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Frame

Gets or sets the frame for the view. The frame is relative to the view's container (SuperView).
Declaration
public override Rect Frame { get; set; }
Property Value
Type Description
Rect The frame.
Overrides
Remarks

Change the Frame when using the Absolute layout style to move or resize views.

Altering the Frame of a view will trigger the redrawing of the view as well as the redrawing of the affected regions of the SuperView.

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Position

Gets the current character position starting at one, related to the Stream.
Declaration
public long Position { get; }
Property Value
Type Description
long
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Source

Sets or gets the Stream the HexView is operating on; the stream must support seeking (CanSeek == true).
Declaration
public Stream Source { get; set; }
Property Value
Type Description
Stream The source.

Methods

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ApplyEdits(Stream)

This method applies and edits made to the Stream and resets the contents of the Edits property.
Declaration
public void ApplyEdits(Stream stream = null)
Parameters
Type Name Description
Stream stream If provided also applies the changes to the passed Stream
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DiscardEdits()

This method discards the edits made to the Stream by resetting the contents of the Edits property.
Declaration
public void DiscardEdits()
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MouseEvent(MouseEvent)

Method invoked when a mouse event is generated
Declaration
public override bool MouseEvent(MouseEvent me)
Parameters
Type Name Description
MouseEvent me
Returns
Type Description
bool true, if the event was handled, false otherwise.
Overrides
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OnEdited(KeyValuePair<long, byte>)

Method used to invoke the Edited event passing the KeyValuePair<TKey, TValue>.
Declaration
public virtual void OnEdited(KeyValuePair<long, byte> keyValuePair)
Parameters
Type Name Description
KeyValuePair<long, byte> keyValuePair The key value pair.
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OnEnter(View)

Method invoked when a view gets focus.
Declaration
public override bool OnEnter(View view)
Parameters
Type Name Description
View view The view that is losing focus.
Returns
Type Description
bool true, if the event was handled, false otherwise.
Overrides
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OnPositionChanged()

Method used to invoke the PositionChanged event passing the HexView.HexViewEventArgs arguments.
Declaration
public virtual void OnPositionChanged()
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PositionCursor()

Positions the cursor in the right position based on the currently focused view in the chain.
Declaration
public override void PositionCursor()
Overrides
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ProcessKey(KeyEvent)

If the view is focused, gives the view a chance to process the keystroke.
Declaration
public override bool ProcessKey(KeyEvent keyEvent)
Parameters
Type Name Description
KeyEvent keyEvent Contains the details about the key that produced the event.
Returns
Type Description
bool
Overrides
Remarks

Views can override this method if they are interested in processing the given keystroke. If they consume the keystroke, they must return true to stop the keystroke from being processed by other widgets or consumed by the widget engine. If they return false, the keystroke will be passed using the ProcessColdKey method to other views to process.

The View implementation does nothing but return false, so it is not necessary to call base.ProcessKey if you derive directly from View, but you should if you derive other View subclasses.

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Redraw(Rect)

Redraws this view and its subviews; only redraws the views that have been flagged for a re-display.
Declaration
public override void Redraw(Rect bounds)
Parameters
Type Name Description
Rect bounds The bounds (view-relative region) to redraw.
Overrides
Remarks

Always use Bounds (view-relative) when calling Redraw(Rect), NOT Frame (superview-relative).

Views should set the color that they want to use on entry, as otherwise this will inherit the last color that was set globally on the driver.

Overrides of Redraw(Rect) must ensure they do not set Driver.Clip to a clip region larger than the parameter, as this will cause the driver to clip the entire region.

Events

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Edited

Event to be invoked when an edit is made on the Stream.
Declaration
public event Action<KeyValuePair<long, byte>> Edited
Event Type
Type Description
Action<KeyValuePair<long, byte>>
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PositionChanged

Event to be invoked when the position and cursor position changes.
Declaration
public event Action<HexView.HexViewEventArgs> PositionChanged
Event Type
Type Description
Action<HexView.HexViewEventArgs>

Implements