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

The caret must be inside a table cell. If it is not, the call is a no-op.

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

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) Is 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

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

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.

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

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

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 Is "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 for the table currently under the caret. The manipulator exposes lower-level row/column DOM helpers used internally by the service.

Syntax

ITableManipulator GetTableManipulator();

Returns

An ITableManipulator scoped to the active table, or null when the caret is not inside a table.

Example

var manipulator = htmlEditor1.Content.TableAuthoringService.GetTableManipulator();
if (manipulator != null)
{
    Debug.WriteLine($"Caret is inside a table; CanMerge={manipulator.CanMerge()}");
}

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

If manipulator IsNot Nothing Then
    Debug.WriteLine($"Caret is inside a table; CanMerge={manipulator.CanMerge()}")
End If

ResetTableManipulator()

Discards the cached ITableManipulator so the next call to GetTableManipulator re-queries the MSHTML DOM. Call this after a programmatic edit you suspect invalidated the cached state -- for example, after replacing the document HTML wholesale.

Syntax

void ResetTableManipulator();

Example

htmlEditor1.Content.LoadBodyHtml("<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.

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