Class HtmlContainer

Low level handling of Html Renderer logic, this class is used by HtmlLabel and HtmlPanel.

Inheritance

object

HtmlContainer

Implements

IDisposable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: MewExtendedToolkit.Html

Assembly: MewExtendedToolkit.Html.dll

Syntax

public sealed class HtmlContainer : IDisposable

Constructors

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HtmlContainer()

Init.

Declaration

public HtmlContainer()

Properties

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ActualSize

The actual size of the rendered html (after layout)

Declaration

public Size ActualSize { get; }

Property Value

Type	Description
Size

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AvoidAsyncImagesLoading

Gets or sets a value indicating if image asynchronous loading should be avoided (default - false).
True - images are loaded synchronously during html parsing.
False - images are loaded asynchronously to html parsing when downloaded from URL or loaded from disk.

Declaration

public bool AvoidAsyncImagesLoading { get; set; }

Property Value

Type	Description
bool

Remarks

Asynchronously image loading allows to unblock html rendering while image is downloaded or loaded from disk using IO ports to achieve better performance.
Asynchronously image loading should be avoided when the full html content must be available during render, like render to image.

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AvoidImagesLateLoading

Gets or sets a value indicating if image loading only when visible should be avoided (default - false).
True - images are loaded as soon as the html is parsed.
False - images that are not visible because of scroll location are not loaded until they are scrolled to.

Declaration

public bool AvoidImagesLateLoading { get; set; }

Property Value

Type	Description
bool

Remarks

Images late loading improve performance if the page contains image outside the visible scroll area, especially if there is large amount of images, as all image loading is delayed (downloading and loading into memory).
Late image loading may effect the layout and actual size as image without set size will not have actual size until they are loaded resulting in layout change during user scroll.
Early image loading may also effect the layout if image without known size above the current scroll location are loaded as they will push the html elements down.

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CssData

the parsed stylesheet data used for handling the html

Declaration

public CssData CssData { get; }

Property Value

Type	Description
CssData

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IsContextMenuEnabled

Is the build-in context menu enabled and will be shown on mouse right click (default - true)

Declaration

public bool IsContextMenuEnabled { get; set; }

Property Value

Type	Description
bool

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IsSelectionEnabled

Is content selection is enabled for the rendered html (default - true).
If set to 'false' the rendered html will be static only with ability to click on links.

Declaration

public bool IsSelectionEnabled { get; set; }

Property Value

Type	Description
bool

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Location

The top-left most location of the rendered html.
This will offset the top-left corner of the rendered html.

Declaration

public Point Location { get; set; }

Property Value

Type	Description
Point

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MaxSize

The max width and height of the rendered html.
The max width will effect the html layout wrapping lines, resize images and tables where possible.
The max height does NOT effect layout, but will not render outside it (clip).
ActualSize can be exceed the max size by layout restrictions (unwrappable line, set image size, etc.).
Set zero for unlimited (width\height separately).

Declaration

public Size MaxSize { get; set; }

Property Value

Type	Description
Size

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ScrollOffset

The scroll offset of the html.
This will adjust the rendered html by the given offset so the content will be "scrolled".

Declaration

public Point ScrollOffset { get; set; }

Property Value

Type	Description
Point

Examples

Element that is rendered at location (50,100) with offset of (0,200) will not be rendered as it will be at -100 therefore outside the client Rect.

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SelectedHtml

Copy the currently selected html segment with style.

Declaration

public string SelectedHtml { get; }

Property Value

Type	Description
string

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SelectedText

Get the currently selected text segment in the html.

Declaration

public string SelectedText { get; }

Property Value

Type	Description
string

Methods

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Clear()

Clear the content of the HTML container releasing any resources used to render previously existing content.

Declaration

public void Clear()

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ClearSelection()

Clear the current selection.

Declaration

public void ClearSelection()

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Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

Declaration

public void Dispose()

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GetAttributeAt(Point, string)

Get attribute value of element at the given x,y location by given key.
If more than one element exist with the attribute at the location the inner most is returned.

Declaration

public string GetAttributeAt(Point location, string attribute)

Parameters

Type	Name	Description
Point	location	the location to find the attribute at
string	attribute	the attribute key to get value by

Returns

Type	Description
string	found attribute value or null if not found

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GetElementRectangle(string)

Get the Rect of html element as calculated by html layout.
Element if found by id (id attribute on the html element).
Note: to get the screen Rect you need to adjust by the hosting control.

Declaration

public Rect? GetElementRectangle(string elementId)

Parameters

Type	Name	Description
string	elementId	the id of the element to get its Rect

Returns

Type	Description
Rect?	the Rect of the element or null if not found

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GetHtml(HtmlGenerationStyle)

Get html from the current DOM tree with style if requested.

Declaration

public string GetHtml(HtmlGenerationStyle styleGen = HtmlGenerationStyle.Inline)

Parameters

Type	Name	Description
HtmlGenerationStyle	styleGen	Optional: controls the way styles are generated when html is generated (default: TheArtOfDev.HtmlRenderer.Core.Entities.HtmlGenerationStyle.Inline)

Returns

Type	Description
string	generated html

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GetLinkAt(Point)

Get css link href at the given x,y location.

Declaration

public string GetLinkAt(Point location)

Parameters

Type	Name	Description
Point	location	the location to find the link at

Returns

Type	Description
string	css link href if exists or null

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GetLinks()

Get all the links in the HTML with the element Rect and href data.

Declaration

public List<LinkElementData<Rect>> GetLinks()

Returns

Type	Description
List<LinkElementData<Rect>>	collection of all the links in the HTML

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HandleKeyDown(Control, KeyEventArgs)

Handle key down event for selection and copy.

Declaration

public void HandleKeyDown(Control parent, KeyEventArgs e)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to invalidate
KeyEventArgs	e	the pressed key

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HandleMouseDoubleClick(Control, MouseEventArgs)

Handle mouse double click to select word under the mouse.

Declaration

public void HandleMouseDoubleClick(Control parent, MouseEventArgs e)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to set cursor and invalidate
MouseEventArgs	e	mouse event args

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HandleMouseDown(Control, MouseEventArgs)

Handle mouse down to handle selection.

Declaration

public void HandleMouseDown(Control parent, MouseEventArgs e)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to invalidate
MouseEventArgs	e	the mouse event args

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HandleMouseLeave(Control)

Handle mouse leave to handle hover cursor.

Declaration

public void HandleMouseLeave(Control parent)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to set cursor and invalidate

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HandleMouseMove(Control, Point)

Handle mouse move to handle hover cursor and text selection.

Declaration

public void HandleMouseMove(Control parent, Point mousePos)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to set cursor and invalidate
Point	mousePos	the mouse event args

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HandleMouseUp(Control, MouseEventArgs)

Handle mouse up to handle selection and link click.

Declaration

public void HandleMouseUp(Control parent, MouseEventArgs e)

Parameters

Type	Name	Description
Control	parent	the control hosting the html to invalidate
MouseEventArgs	e	the mouse event args

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PerformLayout()

Measures the bounds of box and children, recursively.

Declaration

public void PerformLayout()

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PerformPaint(IGraphicsContext, Rect)

Render the html using the given device.

Declaration

public void PerformPaint(IGraphicsContext g, Rect clip)

Parameters

Type	Name	Description
IGraphicsContext	g	the device to use to render
Rect	clip	the clip rectangle of the html container

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SetHtml(string, CssData?)

Init with optional document and stylesheet.

Declaration

public void SetHtml(string htmlSource, CssData? baseCssData = null)

Parameters

Type	Name	Description
string	htmlSource	the html to init with, init empty if not given
CssData	baseCssData	optional: the stylesheet to init with, init default if not given

Events

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ImageLoad

Raised when an image is about to be loaded by file path or URI.
This event allows to provide the image manually, if not handled the image will be loaded from file or download from URI.

Declaration

public event EventHandler<HtmlImageLoadEventArgs> ImageLoad

Event Type

Type	Description
EventHandler<HtmlImageLoadEventArgs>

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LinkClicked

Raised when the user clicks on a link in the html.
Allows canceling the execution of the link.

Declaration

public event EventHandler<HtmlLinkClickedEventArgs> LinkClicked

Event Type

Type	Description
EventHandler<HtmlLinkClickedEventArgs>

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LoadComplete

Raised when the set html document has been fully loaded.
Allows manipulation of the html dom, scroll position, etc.

Declaration

public event EventHandler LoadComplete

Event Type

Type	Description
EventHandler

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Refresh

Raised when html renderer requires refresh of the control hosting (invalidation and re-layout).

Declaration

public event EventHandler<HtmlRefreshEventArgs> Refresh

Event Type

Type	Description
EventHandler<HtmlRefreshEventArgs>

Remarks

There is no guarantee that the event will be raised on the main thread, it can be raised on thread-pool thread.

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RenderError

Raised when an error occurred during html rendering.

Declaration

public event EventHandler<HtmlRenderErrorEventArgs> RenderError

Event Type

Type	Description
EventHandler<HtmlRenderErrorEventArgs>

Remarks

There is no guarantee that the event will be raised on the main thread, it can be raised on thread-pool thread.

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ScrollChange

Raised when Html Renderer request scroll to specific location.
This can occur on document anchor click.

Declaration

public event EventHandler<HtmlScrollEventArgs> ScrollChange

Event Type

Type	Description
EventHandler<HtmlScrollEventArgs>

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StylesheetLoad

Raised when a stylesheet is about to be loaded by file path or URI by link element.
This event allows to provide the stylesheet manually or provide new source (file or Uri) to load from.
If no alternative data is provided the original source will be used.

Declaration

public event EventHandler<HtmlStylesheetLoadEventArgs> StylesheetLoad

Event Type

Type	Description
EventHandler<HtmlStylesheetLoadEventArgs>

Implements

IDisposable