Table Authoring Service

The Content.TableAuthoringService property on WinFormHtmlEditor exposes an ITableAuthoringService instance. The service owns every table-editing operation the user can perform from the table toolbar -- insert column, insert row, delete row, merge cells, and the zero-border guideline overlay. Calling these members from code is the supported way to drive table editing from a custom toolbar, a hotkey, or an automation script.

Namespace: SpiceLogic.HtmlEditor.Abstractions.Services.ElementAuthoring
Assembly: SpiceLogic.HtmlEditor.Abstractions.dll
Accessor: htmlEditor1.Content.TableAuthoringService

The service implements IDisposable; the editor owns its lifetime, so customer code never needs to call Dispose directly.

InsertColumn(InsertPositions position)

Inserts a new column adjacent to the table cell that currently contains the caret.

Syntax

void InsertColumn(InsertPositions position);

Parameters

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode and the caret is inside a table cell.

Example

using SpiceLogic.HtmlEditor.Abstractions;
using SpiceLogic.HtmlEditor.Abstractions.Services.ElementAuthoring;

ITableAuthoringService tables = htmlEditor1.Content.TableAuthoringService;
// Insert a column to the right of the column under the caret.
tables.InsertColumn(InsertPositions.After);

Imports SpiceLogic.HtmlEditor.Abstractions
Imports SpiceLogic.HtmlEditor.Abstractions.Services.ElementAuthoring

Dim tables As ITableAuthoringService = htmlEditor1.Content.TableAuthoringService
' Insert a column to the right of the column under the caret.
tables.InsertColumn(InsertPositions.After)

DeleteColumn()

Removes the column that contains the current cell from the table.

Syntax

void DeleteColumn();

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode and the caret is inside a table cell. If the column is the only column in the table, the entire table is removed.

Example

if (MessageBox.Show("Delete this column?", "Confirm", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
    htmlEditor1.Content.TableAuthoringService.DeleteColumn();
}

If MessageBox.Show("Delete this column?", "Confirm", MessageBoxButtons.YesNo) = DialogResult.Yes Then
    htmlEditor1.Content.TableAuthoringService.DeleteColumn()
End If

InsertRow(InsertPositions position)

Inserts a new row adjacent to the row that contains the caret.

Syntax

void InsertRow(InsertPositions position);

Parameters

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode and the caret is inside a table cell.

Example

// Hot-key handler for Ctrl+Enter -- append a new row below.
private void AppendRow_Click(object sender, EventArgs e)
{
    htmlEditor1.Content.TableAuthoringService.InsertRow(InsertPositions.After);
}

' Hot-key handler for Ctrl+Enter -- append a new row below.
Private Sub AppendRow_Click(sender As Object, e As EventArgs)
    htmlEditor1.Content.TableAuthoringService.InsertRow(InsertPositions.After)
End Sub

DeleteRow()

Removes the row that contains the caret from the table.

Syntax

void DeleteRow();

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode and the caret is inside a table cell. If the row is the only row in the table, the entire table is removed.

Example

htmlEditor1.Content.TableAuthoringService.DeleteRow();

MergeSelectedCells()

Merges the currently selected table cells into one. Styling on the resulting cell is inherited from the top-left source cell.

Syntax

void MergeSelectedCells();

Remarks

The call is a no-op when CanMergeCells() returns false or when EnableTableCellMerging is false. Guard custom toolbar buttons with CanMergeCells() so their enabled state matches. Unlike the row and column operations above, this runs regardless of editor mode.

Example

var tables = htmlEditor1.Content.TableAuthoringService;
if (tables.CanMergeCells())
{
    tables.MergeSelectedCells();
}

Dim tables = htmlEditor1.Content.TableAuthoringService

If tables.CanMergeCells() Then
    tables.MergeSelectedCells()
End If

ShowGuidelinesForTablesWithZeroBorder(bool inBackground = false)

Renders a dashed guideline overlay around every table whose border attribute is 0. The guideline is purely a visual aid -- it is not serialized into the document HTML.

Syntax

void ShowGuidelinesForTablesWithZeroBorder(bool inBackground = false);

Parameters

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode. The guideline CSS is customizable via Options.ZeroBorderTableGuidelineCss.

Example

// Toggle the guideline overlay from a toolbar button.
htmlEditor1.Content.TableAuthoringService
    .ShowGuidelinesForTablesWithZeroBorder();

HideGuidelinesOfTablesWithZeroBorder(bool inBackground = false)

Removes the dashed guideline overlay added by ShowGuidelinesForTablesWithZeroBorder.

Syntax

void HideGuidelinesOfTablesWithZeroBorder(bool inBackground = false);

Parameters

Remarks

Silently does nothing unless the editor is in EditorModes.WysiwygDesign mode.

Example

htmlEditor1.Content.TableAuthoringService
    .HideGuidelinesOfTablesWithZeroBorder();

IsTableBorderZero(IHTMLElement tableElement)

Tests whether a given <table> element has an effective border of zero -- via the border="0" attribute or via CSS that resolves to no visible border.

Syntax

bool IsTableBorderZero(IHTMLElement tableElement);

Parameters

Returns

true when the table has no visible border; otherwise false.

Example

using mshtml;

var tables = htmlEditor1.Content.TableAuthoringService;
IHTMLElement selected = htmlEditor1.StateQuery.GetActiveHtmlElement();
if (selected?.tagName == "TABLE" && tables.IsTableBorderZero(selected))
{
    tables.ShowGuidelinesForTablesWithZeroBorder();
}

Imports mshtml

Dim tables = htmlEditor1.Content.TableAuthoringService
Dim selected As IHTMLElement = htmlEditor1.StateQuery.GetActiveHtmlElement()

If selected?.tagName = "TABLE" AndAlso tables.IsTableBorderZero(selected) Then
    tables.ShowGuidelinesForTablesWithZeroBorder()
End If

CanMergeCells()

Reports whether the current selection covers two or more adjacent cells eligible for merging.

Syntax

bool CanMergeCells();

Returns

true when cells can be merged; otherwise false.

Remarks

Bind this to the Enabled of a custom Merge-Cells toolbar button inside SelectionChanged so the button greys out automatically when merging is not possible.

Example

htmlEditor1.SelectionChanged += (s, e) =>
{
    mergeButton.Enabled = htmlEditor1.Content.TableAuthoringService.CanMergeCells();
};

GetTableManipulator()

Returns the ITableManipulator state-query helper, created once per document the first time it is requested and cached from then on -- it is not re-created per call or scoped to the caret. Its public surface is a single state-query member, CanMerge(), which CanMergeCells forwards to.

Syntax

ITableManipulator GetTableManipulator();

Returns

The current ITableManipulator instance. It is never null, regardless of caret position; call ResetTableManipulator to force a fresh instance.

Example

var manipulator = htmlEditor1.Content.TableAuthoringService.GetTableManipulator();
Debug.WriteLine($"Selection can be merged: {manipulator.CanMerge()}");

Dim manipulator = htmlEditor1.Content.TableAuthoringService.GetTableManipulator()

Debug.WriteLine($"Selection can be merged: {manipulator.CanMerge()}")

ResetTableManipulator()

Immediately disposes the cached ITableManipulator and creates a fresh one, rather than deferring the re-creation to the next GetTableManipulator call. Call this after a programmatic edit you suspect invalidated the cached state -- for example, after replacing the document HTML wholesale.

Syntax

void ResetTableManipulator();

Remarks

This also re-derives EnableTableCellMerging from Options.EnableTableCellMerge, discarding any value set directly on the property beforehand.

Example

htmlEditor1.Content.SetBodyHtml("<table border=\"1\"><tr><td>A</td></tr></table>");
htmlEditor1.Content.TableAuthoringService.ResetTableManipulator();

SelectedCellBackgroundColor Property

Gets or sets the background color used to highlight selected table cells on the editor surface. This is a UI-only highlight; it does not emit a background-color style on the cells themselves.

Syntax

Color SelectedCellBackgroundColor { get; set; }

Property Value

A System.Drawing.Color. The default is a light-blue overlay; pick any color that contrasts with your document background.

Example

using System.Drawing;

htmlEditor1.Content.TableAuthoringService.SelectedCellBackgroundColor = Color.FromArgb(120, 255, 230, 0); // semi-transparent yellow

Imports System.Drawing

htmlEditor1.Content.TableAuthoringService.SelectedCellBackgroundColor = Color.FromArgb(120, 255, 230, 0) ' semi-transparent yellow

EnableTableCellMerging Property

Gets or sets whether the cell-merging feature is enabled. When false, MergeSelectedCells is a no-op and the editor suppresses any cell-selection UI.

Syntax

bool EnableTableCellMerging { get; set; }

Property Value

true to allow cell merging; false to disable it. This is initialized from Options.EnableTableCellMerge at startup, and again every time ResetTableManipulator runs.

Example

// Disable cell merging for a simplified authoring mode.
htmlEditor1.Content.TableAuthoringService.EnableTableCellMerging = false;

' Disable cell merging for a simplified authoring mode.
htmlEditor1.Content.TableAuthoringService.EnableTableCellMerging = False

Ask your AI to do this

Using the SpiceLogic WinForms HTML Editor already referenced in my project, build a small custom toolbar with an "Add column" button that calls InsertColumn on the editor's Content.TableAuthoringService (typed as ITableAuthoringService) to insert a column next to whatever table cell currently holds the caret. Add a second button that removes the current row through the same service, so both actions work from my own toolbar instead of the built-in table commands. Pull the exact ITableAuthoringService method signatures with the SpiceLogic MCP tools before writing any code.