Editor Service

The Editor Service is the central programmatic surface of the WPF HTML Editor. Reach it through the Editor property of WpfHtmlEditor; it exposes the IEditorService contract through the marker interface IEditorServiceBase that the WPF binding implements.

The service covers four broad areas: layout (resizing and scroll bars), the clipboard pipeline (cut, copy, paste, including MS Word paste), command execution (undo, redo, justification, generic exec-commands), and search-and-replace including the IE-style dialog and programmatic variants.

All members operate against the currently loaded document. Methods that depend on a focused selection (for example Cut or JustifyLeft) silently no-op when the editor has no selection or no focus. In every example below, MyEditor is a WpfHtmlEditor declared in XAML with x:Name="MyEditor".

AdjustEditorSize Method

Resizes the editor control so both its width and height match the natural size of the rendered content. Equivalent to calling AdjustEditorWidth followed by AdjustEditorHeight.

Syntax

void AdjustEditorSize();

Example

private void MyEditor_DocumentReady(object sender, EventArgs e)
{
    // Auto-grow the editor to fit the loaded document.
    MyEditor.Editor.AdjustEditorSize();
}

Private Sub MyEditor_DocumentReady(sender As Object, e As EventArgs)
    ' Auto-grow the editor to fit the loaded document.
    MyEditor.Editor.AdjustEditorSize()
End Sub

AdjustEditorWidth Method

Resets the control's width so that the horizontal scroll bar is no longer needed to reveal clipped content; the editor expands or shrinks to match the visible content width.

Syntax

void AdjustEditorWidth();

Example

private void FitWidthButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.AdjustEditorWidth();
}

Private Sub FitWidthButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.AdjustEditorWidth()
End Sub

AdjustEditorHeight Method

Resets the control's height so that the vertical scroll bar is no longer needed; the editor expands or shrinks to match the visible content height. Pair with AdjustEditorWidth to produce an auto-sized editor.

Syntax

void AdjustEditorHeight();

Example

private void FitHeightButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.AdjustEditorHeight();
}

Private Sub FitHeightButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.AdjustEditorHeight()
End Sub

GetScrollBarSetting Method

Returns the editor's current scroll-bar policy as a ScrollBarVisibility value (Auto, Both, Horizontal, Vertical, None, Default, or Custom).

Syntax

ScrollBarVisibility GetScrollBarSetting();

Returns

ScrollBarVisibility - the active scroll-bar policy.

Example

ScrollBarVisibility before = MyEditor.Editor.GetScrollBarSetting();

MyEditor.Editor.SetScrollBarSetting(ScrollBarVisibility.None);

PrintDocument();

MyEditor.Editor.SetScrollBarSetting(before); // restore

SetScrollBarSetting Method

Changes the editor's scroll-bar policy. Use Custom if you supply your own overflow CSS through BodyStyle; in Custom mode the editor leaves your style untouched.

Syntax

void SetScrollBarSetting(ScrollBarVisibility scrollbarValue);

Parameters

Example

// Show both scrollbars only when content overflows.

MyEditor.Editor.SetScrollBarSetting(ScrollBarVisibility.Auto);

GetScrollPosition Method

Returns the current scroll offset of the editor viewport as a System.Drawing.Point in pixels.

Syntax

System.Drawing.Point GetScrollPosition();

Returns

System.Drawing.Point - X is the horizontal scroll offset and Y is the vertical scroll offset.

Example

var saved = MyEditor.Editor.GetScrollPosition();
MyEditor.LoadHtml(updatedHtml);
MyEditor.Editor.SetScrollPosition(saved.X, saved.Y);

Dim saved = MyEditor.Editor.GetScrollPosition()
MyEditor.LoadHtml(updatedHtml)
MyEditor.Editor.SetScrollPosition(saved.X, saved.Y)

SetScrollPosition Method

Scrolls the editor viewport to the absolute pixel offset (x, y). Values are clamped to the valid scroll range of the current document.

Syntax

void SetScrollPosition(int x, int y);

Parameters

Example

// Jump back to the top of the document.

MyEditor.Editor.SetScrollPosition(0, 0);

IsMsWordContentInClipboard Method

Returns true when the system clipboard holds content originating from Microsoft Word (detected via Word-specific clipboard formats). Use it to decide whether to offer a Paste from Word command in your UI.

Syntax

bool IsMsWordContentInClipboard();

Returns

System.Boolean - true if MS Word content is on the clipboard; otherwise false.

Example

PasteFromWordButton.IsEnabled =

    MyEditor.Editor.IsMsWordContentInClipboard();

PasteFromMsWord Method

Pastes clipboard content using the editor's Word-aware cleaning pipeline. Word-specific markup such as MSO conditional comments, mso-* CSS, and VML imagedata is stripped before the content is inserted.

Syntax

void PasteFromMsWord();

Example

if (MyEditor.Editor.IsMsWordContentInClipboard())
    MyEditor.Editor.PasteFromMsWord();
else
    MyEditor.Editor.Paste();

If MyEditor.Editor.IsMsWordContentInClipboard() Then
    MyEditor.Editor.PasteFromMsWord()
Else
    MyEditor.Editor.Paste()
End If

Cut Method

Performs a standard cut: removes the current selection from the document and places it on the system clipboard. No-op when the selection is empty.

Syntax

void Cut();

Example

private void CutCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
    MyEditor.Editor.Cut();
}

Private Sub CutCommand_Executed(sender As Object, e As ExecutedRoutedEventArgs)
    MyEditor.Editor.Cut()
End Sub

Copy Method

Copies the current selection to the system clipboard without modifying the document. No-op when the selection is empty.

Syntax

void Copy();

Example

private void CopyCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
    MyEditor.Editor.Copy();
}

Private Sub CopyCommand_Executed(sender As Object, e As ExecutedRoutedEventArgs)
    MyEditor.Editor.Copy()
End Sub

Delete Method

Deletes the current selection from the document. When there is no selection, deletes the character to the right of the caret (forward delete).

Syntax

void Delete();

Example

private void DeleteCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
    MyEditor.Editor.Delete();
}

Private Sub DeleteCommand_Executed(sender As Object, e As ExecutedRoutedEventArgs)
    MyEditor.Editor.Delete()
End Sub

Paste Method

Pastes clipboard content at the caret position using the editor's standard paste pipeline. For Word-origin clipboards prefer PasteFromMsWord to apply Word-specific cleaning.

Syntax

void Paste();

Example

private void PasteCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
    MyEditor.Editor.Paste();
}

Private Sub PasteCommand_Executed(sender As Object, e As ExecutedRoutedEventArgs)
    MyEditor.Editor.Paste()
End Sub

Undo Method

Reverts the most recent edit. The undo stack covers typing, formatting, and structural changes; see ClearUndoStack to reset it.

Syntax

void Undo();

Example

private void UndoButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.Undo();
}

Private Sub UndoButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.Undo()
End Sub

Redo Method

Reapplies the most recently undone edit. The redo stack is cleared whenever a new edit is made after an undo.

Syntax

void Redo();

Example

private void RedoButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.Redo();
}

Private Sub RedoButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.Redo()
End Sub

ToggleOverWriteMode Method

Switches the editor between insert mode and overwrite mode, mirroring the effect of the Insert key. In overwrite mode each typed character replaces the character under the caret.

Syntax

void ToggleOverWriteMode();

Example

private void InsertKeyBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
    MyEditor.Editor.ToggleOverWriteMode();
}

Private Sub InsertKeyBinding_Executed(sender As Object, e As ExecutedRoutedEventArgs)
    MyEditor.Editor.ToggleOverWriteMode()
End Sub

Print Method

Prints the current document. When showDialog is true the standard Windows print dialog is shown first so the user can choose a printer and options; otherwise the default printer is used silently.

Syntax

void Print(bool showDialog);

Parameters

Remarks

If no printer is installed on the machine the editor shows a message box; the caption of that box is controlled by NoPrinterMessageCaption.

Example

private void PrintButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.Print(showDialog: true);
}

Private Sub PrintButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.Print(showDialog:=True)
End Sub

ExecCommand Method

Executes one of the underlying browser exec-commands (the same command identifiers used by the legacy document.execCommand DOM API). Useful as an escape hatch when a built-in editor method does not cover the operation you need.

Syntax

void ExecCommand(string cmdId, bool showUi = false, object? value = null);

Parameters

Example

// Apply a red foreground colour to the current selection.
MyEditor.Editor.ExecCommand("ForeColor", false, "#cc0000");

' Apply a red foreground colour to the current selection.
MyEditor.Editor.ExecCommand("ForeColor", False, "#cc0000")

ShowPrintPreviewDialog Method

Opens the system print-preview dialog showing how the current document will appear on paper. The dialog is modal with respect to the editor's host window.

Syntax

void ShowPrintPreviewDialog();

Example

private void PrintPreviewButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.ShowPrintPreviewDialog();
}

Private Sub PrintPreviewButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.ShowPrintPreviewDialog()
End Sub

ShowPageSetupDialog Method

Opens the system page-setup dialog so the user can adjust margins, orientation, and paper size. Settings chosen here apply to subsequent Print and ShowPrintPreviewDialog calls.

Syntax

void ShowPageSetupDialog();

Example

private void PageSetupButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.ShowPageSetupDialog();
}

Private Sub PageSetupButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.ShowPageSetupDialog()
End Sub

JustifyLeft Method

Toggles left-justification on the block containing the caret. Calling the method twice removes the justification.

Syntax

void JustifyLeft();

Example

private void AlignLeftButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.JustifyLeft();
}

Private Sub AlignLeftButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.JustifyLeft()
End Sub

JustifyRight Method

Toggles right-justification on the block containing the caret.

Syntax

void JustifyRight();

Example

private void AlignRightButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.JustifyRight();
}

Private Sub AlignRightButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.JustifyRight()
End Sub

JustifyCenter Method

Toggles centred justification on the block containing the caret.

Syntax

void JustifyCenter();

Example

private void AlignCenterButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.JustifyCenter();
}

Private Sub AlignCenterButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.JustifyCenter()
End Sub

Search Method

Searches the document for the next or previous occurrence of text. When a match is found the editor selects it and scrolls it into view; the method returns true. When no match is found nothing is selected and the method returns false.

Syntax

bool Search(string text, bool forward, bool matchWholeWord, bool matchCase, bool useCaretPosition = false);

Parameters

Returns

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

Example

bool found = MyEditor.Editor.Search(text: "invoice", forward: true, matchWholeWord: false, matchCase: false);
if (!found)
    MessageBox.Show("No more matches.");

Dim found As Boolean = MyEditor.Editor.Search(text:="invoice", forward:=True, matchWholeWord:=False, matchCase:=False)
If Not found Then MessageBox.Show("No more matches.")

Replace Method

If the current selection equals searchString (subject to the case and whole-word flags), replaces it with replacement. Returns true when a replacement actually happened. Typically called in a loop with Search to implement an interactive Find and Replace workflow.

Syntax

bool Replace(string searchString, string replacement, bool matchWholeWord, bool matchCase);

Parameters

Returns

System.Boolean - true if the selection matched and was replaced; otherwise false.

Example

// Interactive workflow: Find, then Replace on user click.
if (MyEditor.Editor.Search("colour", true, false, false))
{
    MyEditor.Editor.Replace("colour", "color", false, false);
}

' Interactive workflow: Find, then Replace on user click.
If MyEditor.Editor.Search("colour", True, False, False) Then
    MyEditor.Editor.Replace("colour", "color", False, False)
End If

ReplaceAll Method

Replaces every occurrence of replaceWhat in the document with replaceWith. Returns the number of replacements performed.

Syntax

int ReplaceAll(string replaceWhat, string replaceWith, bool matchWholeWord, bool matchCase);

Parameters

Returns

System.Int32 - the number of occurrences found and replaced.

Example

int n = MyEditor.Editor.ReplaceAll(replaceWhat: "colour", replaceWith: "color", matchWholeWord: true, matchCase: false);
MessageBox.Show($"Replaced {n} occurrence(s).");

Dim n As Integer = MyEditor.Editor.ReplaceAll(replaceWhat:="colour", replaceWith:="color", matchWholeWord:=True, matchCase:=False)
MessageBox.Show($"Replaced {n} occurrence(s).")

SearchWithDefaultIeDialog Method

Opens the built-in IE-style search dialog so the end user can interactively find text within the editor. The dialog raises the editor's search-related events (see SearchEventArg, ReplaceEventArg, ReplaceAllEventArg).

Syntax

void SearchWithDefaultIeDialog();

Example

private void FindButton_Click(object sender, RoutedEventArgs e)
{
    MyEditor.Editor.SearchWithDefaultIeDialog();
}

Private Sub FindButton_Click(sender As Object, e As RoutedEventArgs)
    MyEditor.Editor.SearchWithDefaultIeDialog()
End Sub

DeleteText Method

Deletes length characters starting at the plain-text startIndex. Useful for programmatic editing without disturbing the user's selection.

Syntax

void DeleteText(int startIndex, int length);

Parameters

Example

// Strip the first ten characters of plain text from the document.

MyEditor.Editor.DeleteText(startIndex: 0, length: 10);

ReplaceText Method

Replaces length characters starting at the plain-text startIndex with replacementText. The replacement may be longer or shorter than the original span.

Syntax

void ReplaceText(int startIndex, int length, string replacementText);

Parameters

Example

// Replace 4 characters at offset 12 with a longer word.

MyEditor.Editor.ReplaceText(12, 4, "Hello");

PrintPageSetup Method (Uniform Margin)

Sets uniform page margins (top, bottom, left, and right) for subsequent printing. The value is in inches.

Syntax

void PrintPageSetup(double margin);

Parameters

Example

// One-inch margins, then print silently.
MyEditor.Editor.PrintPageSetup(margin: 1.0);
MyEditor.Editor.Print(showDialog: false);

' One-inch margins, then print silently.
MyEditor.Editor.PrintPageSetup(margin:=1.0)
MyEditor.Editor.Print(showDialog:=False)

PrintPageSetup Method (Per-Side Margins)

Sets per-side page margins for subsequent printing. All values are in inches.

Syntax

void PrintPageSetup(double topMargin, double bottomMargin, double rightMargin, double leftMargin);

Parameters

Example

// Wider left margin for binding.

MyEditor.Editor.PrintPageSetup(

    topMargin:    1.0,

    bottomMargin: 1.0,

    rightMargin:  0.75,

    leftMargin:   1.25);

ClearUndoStack Method

Clears the WYSIWYG editor's undo history. Typically called immediately after loading a document so the user cannot undo past the load point.

Syntax

void ClearUndoStack();

Example

// Load fresh content and prevent users from undoing into the previous document.

MyEditor.LoadHtml(myHtml);

MyEditor.Editor.ClearUndoStack();

HasHorizontalScrollbar Property

Gets a value indicating whether the editor is currently showing a horizontal scroll bar. The value reflects the actual visible state, not the configured policy.

Syntax

bool HasHorizontalScrollbar { get; }

Returns

System.Boolean - true when the horizontal scroll bar is visible; otherwise false.

Example

if (MyEditor.Editor.HasHorizontalScrollbar)
    MyEditor.Editor.AdjustEditorWidth();

If MyEditor.Editor.HasHorizontalScrollbar Then MyEditor.Editor.AdjustEditorWidth()

HasVerticalScrollbar Property

Gets a value indicating whether the editor is currently showing a vertical scroll bar.

Syntax

bool HasVerticalScrollbar { get; }

Returns

System.Boolean - true when the vertical scroll bar is visible; otherwise false.

Example

if (MyEditor.Editor.HasVerticalScrollbar)
    MyEditor.Editor.AdjustEditorHeight();

If MyEditor.Editor.HasVerticalScrollbar Then MyEditor.Editor.AdjustEditorHeight()

NoPrinterMessageCaption Property

Gets or sets the caption of the message box shown when Print or ShowPrintPreviewDialog is invoked on a machine with no printer installed. Localise this string to match your application's language.

Syntax

string NoPrinterMessageCaption { get; set; }

Returns

System.String - the caption of the "no printer" message box.

Example

// Localise the no-printer message caption at startup.

MyEditor.Editor.NoPrinterMessageCaption = "Printer not available";