TColumn

Column class that defines properties for painting rows in a TeeGrid column

Overview

TColumn defines the properties used to paint rows of a TeeGrid column. It includes support for hierarchical columns through the Items property, which can contain sub-columns.

Key Properties

Width · TColumnWidth

Column width. Can be set to automatic (default) or a custom value in pixels or percentage.

Header · TColumnHeader

Text and formatting properties to display the column name at TeeGrid headers. Contains the column’s display text and visual styling.

Items · TColumns

Optional collection of sub-columns. Enables hierarchical column structures where columns can contain nested columns.

Expanded · Boolean · default: "true"

Controls visibility of column sub-columns. When true, displays the column’s sub-columns if they exist.

Visible · Boolean · default: "true"

Controls column visibility. When false, the column is not displayed in the grid.

ReadOnly · Boolean · default: "false"

Enables or disables editing of grid cell content using the keyboard. When true, cells cannot be edited.

Selectable · Boolean · default: "true"

Controls whether the column can be selected by the user.

ParentFormat · Boolean · default: "true"

When true, inherits formatting from the parent column or grid.

DataFormat · TDataFormat

Formatting strings for numbers and date-time data types. Controls how data values are displayed in cells.

Includes properties:

• Float: Format string for floating-point numbers (default: "0.###")
• Date: Format string for date values
• DateTime: Format string for date-time values
• Time: Format string for time values

Format · TFormat

Custom brush, stroke, and font properties for the column. Defines the visual appearance of column cells.

Margins · TMargins

Edge spacing inside grid cells. Controls padding within cells.

TextAlign · TTextAlign

Horizontal and vertical text alignment within cells.

TextAlignment · TColumnTextAlign · default: "Automatic"

Column text alignment mode:

• Automatic: Automatically aligns based on data type (e.g., right-align numbers)
• Custom: Uses the TextAlign property

Locked · TColumnLocked · default: "None"

Locks the column to a specific position:

• None: Column scrolls normally
• Left: Column is locked to the left side
• Right: Column is locked to the right side

Render · TRender

Optional custom render instance used to paint column cell contents. Enables custom drawing logic.

TagObject · TObject

Custom user-defined object associated with the column. Useful for storing additional metadata.

Key Methods

CanDisplay · Boolean

Returns true if the column can be displayed (is visible and has valid width).

HasItems · Boolean

Returns true if the column has sub-columns in its Items collection.

Level · Integer

Returns the hierarchical level of the column. Top-level columns return 0, their children return 1, etc.

Right · Single

Returns the right edge position of the column (Left + Width).

HorizAlign · THorizontalAlign

Returns the effective horizontal alignment for the column based on TextAlignment setting and data type.

ParentColumns · TColumns

Returns the parent TColumns collection that owns this column.

Events

OnPaint · TColumnPaintEvent

Event triggered when painting the column. Allows custom painting logic.

procedure TForm1.Column1Paint(const Sender: TColumn; 
  var AData: TRenderData; var DefaultPaint: Boolean);
begin
  // Custom painting code
  if not DefaultPaint then
  begin
    // Override default painting
  end;
end;

Usage Example

var
  Column: TColumn;
begin
  // Create and configure a column
  Column := Grid.Columns.Add('Customer Name');
  Column.Width.Value := 200;
  Column.ReadOnly := False;
  Column.TextAlignment := TColumnTextAlign.Automatic;
  
  // Configure data formatting
  Column.DataFormat.Float := '0.00';
  Column.DataFormat.Date := 'mm/dd/yyyy';
  
  // Add sub-columns
  Column.Items.Add('First Name');
  Column.Items.Add('Last Name');
  Column.Expanded := True;
end;

Hierarchical Columns

Columns can contain sub-columns through the Items property:

var
  ParentCol, ChildCol: TColumn;
begin
  // Create parent column
  ParentCol := Grid.Columns.Add('Address');
  
  // Add child columns
  ChildCol := ParentCol.Items.Add('Street');
  ChildCol := ParentCol.Items.Add('City');
  ChildCol := ParentCol.Items.Add('State');
  
  // Control visibility of sub-columns
  ParentCol.Expanded := True; // Show sub-columns
end;

Related Classes

• TColumns - Collection of TColumn instances
• TRows - Grid rows class
• TRowGroup - Row group with headers and footers