Selection service

The selection service works with the text or elements currently highlighted in the editor. Use it to select a range, find and select text, read the selected content or clear the selection. Access these operations through the editor control's Selection property.

Diagram highlighting a phrase and mapping it to reading selected text or HTML, formatting it and clearing the selection.

Indexes are zero-based and measure characters in the rendered text stream, not bytes in the HTML source. The companion SelectionInfo object returned by GetSelectionInfo() bundles the start index, length, plain text and HTML of the current selection in a single object, which is the recommended way to snapshot selection state.

Calling a selection method does not change formatting - combine these methods with the Formatting Service when you want to make a structural change and apply formatting to a precise range in a single operation.

Namespace: SpiceLogic.HtmlEditor.Abstractions.Services
Assembly: SpiceLogic.HtmlEditor.Abstractions
Inheritance: ISelectionService : IDisposable

SelectText(Int32, Int32) Method

Selects a contiguous range of characters starting at startIndex and spanning length characters.

Syntax

void SelectText(int startIndex, int length);

Parameters

Name	Type	Description
startIndex	Int32	Zero-based character index where the selection begins.
length	Int32	Number of characters to select.

Returns

None.

Remarks

Indexes count characters in the rendered text stream, not the raw HTML source. In HtmlEdit mode both indexes instead address the raw HTML markup text in the underlying textbox, not the rendered plain text, since the offsets are applied directly to the raw-HTML editor there.

Example

// Select the first 12 characters of the document.

MyEditor.Focus();

MyEditor.Selection.SelectText(0, 12);

SelectText(Int32) Method

Selects from the given start index to the end of the document body.

Syntax

void SelectText(int startIndex);

Parameters

Name	Type	Description
startIndex	Int32	Zero-based character index where the selection begins.

Returns

None.

Remarks

In HtmlEdit mode this only positions the caret at startIndex in the raw-HTML textbox; it does not select through to the end of the text there the way it does in WysiwygDesign mode.

Example

// Select from character 50 to the very end of the body.

MyEditor.Selection.SelectText(50);

Debug.WriteLine($"Tail length: {MyEditor.Selection.GetSelectionLength()}");

SelectText(String, Boolean, Boolean, Boolean) Method

Searches the document for the specified text and, if found, selects the first match in the given direction. This is the same primitive the built-in Find dialog is built on.

Syntax

bool SelectText(string text, bool forward, bool matchWholeWord, bool matchCase);

Parameters

Name	Type	Description
text	String	The search term.
forward	Boolean	`true` to search from the caret toward the end of the document; `false` to search backward.
matchWholeWord	Boolean	`true` to require word-boundary matches.
matchCase	Boolean	`true` for case-sensitive matching.

Returns

true if a match was found and selected; false otherwise.

Remarks

Always returns false in HtmlEdit mode, without searching.

Example

C#VB.NET

if (!MyEditor.Selection.SelectText("TODO", forward: true, matchWholeWord: true, matchCase: false))
{
    MessageBox.Show("No more TODO markers.");
}

If Not MyEditor.Selection.SelectText("TODO", forward:=True, matchWholeWord:=True, matchCase:=False) Then
    MessageBox.Show("No more TODO markers.")
End If

SelectHtmlElement(IHTMLElement) Method

Selects the specified MSHTML element, expanding the selection to cover the entire element. Useful in conjunction with MyEditor.StateQuery.GetActiveHtmlElement() or GetElementFromPoint() to highlight an element identified by some other route (for example a hover or right-click).

Syntax

void SelectHtmlElement(IHTMLElement element);

Parameters

Name	Type	Description
element	mshtml.IHTMLElement	The HTML element to select.

Returns

None.

Remarks

A no-op in HtmlEdit mode.

Example

C#VB.NET

IHTMLElement active = MyEditor.StateQuery.GetActiveHtmlElement();
if (active != null)
{
    MyEditor.Selection.SelectHtmlElement(active);
}

Dim active As IHTMLElement = MyEditor.StateQuery.GetActiveHtmlElement()

If active IsNot Nothing Then
    MyEditor.Selection.SelectHtmlElement(active)
End If

GetSelectionInfo Method

Returns a snapshot of the current selection. SelectionInfo bundles the start index, length, plain text and HTML in one allocation, which is cheaper than calling the individual getters when you need more than one value.

Syntax

SelectionInfo GetSelectionInfo();

Returns

A populated SelectionInfo with StartIndex, Length, Text, and Html. For an empty selection, Length is 0 and the text and html fields are empty strings.

Remarks

In HtmlEdit mode this always returns a SelectionInfo with its fields at default (empty strings, zero); it does not read the raw-HTML textbox's own selection.

Example

C#VB.NET

var info = MyEditor.Selection.GetSelectionInfo();
Debug.WriteLine($"Selected {info.Length} chars: {info.Text}");
Debug.WriteLine($"HTML: {info.Html}");

Dim info = MyEditor.Selection.GetSelectionInfo()
Debug.WriteLine($"Selected {info.Length} chars: {info.Text}")
Debug.WriteLine($"HTML: {info.Html}")

DeselectAll Method

Clears any active selection without altering the caret position. Equivalent in spirit to TextBox.DeselectAll in classic WinForms / WPF text controls.

Syntax

void DeselectAll();

Returns

None.

Example

// Drop the highlight after a programmatic update.

MyEditor.Selection.SelectAll();

MyEditor.Formatting.ChangeFontSize("12px");

MyEditor.Selection.DeselectAll();

Unselect Method

Clears any active selection. Synonym for DeselectAll, retained for backward compatibility with earlier editor versions.

Syntax

void Unselect();

Returns

None.

Example

// Same effect as DeselectAll; provided for source compatibility.

MyEditor.Selection.Unselect();

SelectAll Method

Selects the entire document body. Equivalent to the user pressing Ctrl+A inside the editor.

Syntax

void SelectAll();

Returns

None.

Example

C#VB.NET

MyEditor.Selection.SelectAll();
string body = MyEditor.Selection.GetSelectedText();
Debug.WriteLine($"Body text length: {body.Length}");

MyEditor.Selection.SelectAll()
Dim body As String = MyEditor.Selection.GetSelectedText()
Debug.WriteLine($"Body text length: {body.Length}")

GetSelectedHtml Method

Returns the HTML markup that backs the current selection. Markup is returned as the editor sees it, including inline styles and any wrapping elements (<span>, <b>, etc.).

Syntax

string GetSelectedHtml();

Returns

The selected HTML fragment, or String.Empty when there is no active selection.

Example

C#VB.NET

string html = MyEditor.Selection.GetSelectedHtml();
if (!string.IsNullOrEmpty(html))
{
    Clipboard.SetText(html);
}

Dim html As String = MyEditor.Selection.GetSelectedHtml()

If Not String.IsNullOrEmpty(html) Then
    Clipboard.SetText(html)
End If

GetSelectedText Method

Returns the plain-text content of the current selection with HTML tags stripped.

Syntax

string GetSelectedText();

Returns

The selected text, or String.Empty when there is no active selection.

Example

C#VB.NET

string text = MyEditor.Selection.GetSelectedText();
StatusText.Text = $"Selected: {text}";

Dim text As String = MyEditor.Selection.GetSelectedText()
StatusText.Text = $"Selected: {text}"

TrimSelection(TrimDirections) Method

Shrinks the active selection by removing leading and / or trailing whitespace characters. Returns the trimmed text. Particularly useful after SelectText(string, ...) matches that pulled in surrounding spaces, or after the user double-clicks to select a word and the platform extended the selection a character too far.

Syntax

string TrimSelection(TrimDirections trimDirection = TrimDirections.Both);

Parameters

Name	Type	Description
trimDirection	TrimDirections	One of `Start`, `End`, or `Both` (default).

Returns

The trimmed selection text.

Remarks

Always returns an empty string in HtmlEdit mode - it operates on the live MSHTML selection and does not affect the raw-HTML textbox.

Example

C#VB.NET

MyEditor.Selection.SelectText("  hello world  ", true, false, true);
string clean = MyEditor.Selection.TrimSelection(); // -> "hello world"
Debug.WriteLine(clean);

MyEditor.Selection.SelectText("  hello world  ", True, False, True)
Dim clean As String = MyEditor.Selection.TrimSelection() ' -> "hello world"
Debug.WriteLine(clean)

GetSelectionLength Method

Returns the length, in characters, of the current selection.

Syntax

int GetSelectionLength();

Returns

The selection's character length, or -1 when there is no text-range selection to measure - in HtmlEdit mode, or when the current selection is not a text range (for example, an image or table selected as a whole).

Example

C#VB.NET

if (MyEditor.Selection.GetSelectionLength() == 0)
{
    MessageBox.Show("Please select some text first.");
    return;
}

If MyEditor.Selection.GetSelectionLength() = 0 Then
    MessageBox.Show("Please select some text first.")
    Return
End If

Dispose Method

Inherited from IDisposable. Called by the editor control during teardown - host applications normally do not invoke this directly.

Syntax

void Dispose();

Returns

None.

Example

// Disposing the editor disposes its services automatically.

MyEditor.Dispose();

// Explicit form is rarely needed:

// MyEditor.Selection.Dispose();

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