TIndicator

Special column that displays visual indicators for row state (browsing, editing, or inserting)

Overview

The TIndicator class is a special column that appears as the leftmost column in a TeeGrid, displaying visual symbols to indicate the current state of each row. It shows whether a row is being browsed, edited, or is a new insert row.

Class Hierarchy

TVisibleTextRender
  └── TIndicator

Visual Indicators

The indicator column displays different symbols based on the row state:

• Browse - Triangle pointing right (▶) for the current row
• Edit - Pencil icon indicating the row is being edited
• Insert - Asterisk (*) indicating a new row being inserted

Properties

Visible

property Visible: Boolean; // Inherited from TVisibleTextRender

Controls whether the indicator column is visible.

Default: Inherited from parent class

Example:

TeeGrid1.Indicator.Visible := True;

Width

property Width: TColumnWidth read FWidth write SetWidth;

The width of the indicator column.

Default: DefaultWidth (10 pixels)

Example:

TeeGrid1.Indicator.Width.Pixels := 20;

Format

property Format: TFormat; // Inherited from TVisibleTextRender

The visual formatting (brush, stroke, font) for the indicator column.

Example:

TeeGrid1.Indicator.Format.Brush.Color := clLightBlue;
TeeGrid1.Indicator.Format.Stroke.Color := clBlue;

Font

property Font: TFont; // Inherited from TVisibleTextRender

The font used for indicator symbols.

Example:

TeeGrid1.Indicator.Font.Color := clNavy;
TeeGrid1.Indicator.Font.Size := 10;

Constants

DefaultWidth

const DefaultWidth = 10;

The default width of the indicator column in pixels.

Methods

Constructor Create

Constructor Create(const AChanged: TNotifyEvent); override;

Creates a new TIndicator instance.

Parameters:

• AChanged: Event handler called when indicator properties change

Assign

procedure Assign(Source: TPersistent); override;

Copies indicator properties from another persistent object.

Parameters:

• Source: The source object to copy from

Example:

TeeGrid2.Indicator.Assign(TeeGrid1.Indicator);

Paint

procedure Paint(var AData: TRenderData); override;

Paints the indicator symbol for the current row state.

Parameters:

• AData: Rendering data containing painter and bounds information

TIndicatorState Enumeration

Defines the possible states for the indicator.

TIndicatorState = (Browse, Edit, Insert);

• Browse - Normal browsing mode (shows triangle)
• Edit - Row is being edited (shows pencil icon)
• Insert - New row is being inserted (shows asterisk)

Usage Examples

Enabling the Indicator

procedure EnableIndicator(Grid: TTeeGrid);
begin
  Grid.Indicator.Visible := True;
  Grid.Indicator.Width.Pixels := 15;
end;

Customizing Indicator Appearance

procedure CustomizeIndicator(Grid: TTeeGrid);
begin
  with Grid.Indicator do
  begin
    Visible := True;
    Width.Pixels := 20;
    
    // Set background color
    Format.Brush.Color := clSkyBlue;
    
    // Set border
    Format.Stroke.Color := clBlue;
    Format.Stroke.Size := 1;
    
    // Set symbol color
    Font.Color := clNavy;
    Font.Size := 10;
  end;
end;

Hiding the Indicator

procedure HideIndicator(Grid: TTeeGrid);
begin
  Grid.Indicator.Visible := False;
end;

Checking Indicator State

procedure CheckIndicatorState(Grid: TTeeGrid);
begin
  // The State property is protected and managed internally by the grid
  // It changes based on editing operations
  
  if Grid.Editing.Active then
    ShowMessage('Indicator shows Edit or Insert state')
  else
    ShowMessage('Indicator shows Browse state');
end;

Complete Indicator Setup

procedure SetupIndicatorColumn(Grid: TTeeGrid);
begin
  with Grid.Indicator do
  begin
    // Make indicator visible
    Visible := True;
    
    // Set custom width
    Width.Pixels := 18;
    
    // Light blue background
    Format.Brush.Color := clMoneyGreen;
    Format.Brush.Visible := True;
    
    // Dark border on right side
    Format.Stroke.Color := clGray;
    Format.Stroke.Size := 1;
    Format.Stroke.Visible := True;
    
    // Dark blue symbols
    Font.Color := clNavy;
    Font.Size := 9;
    Font.Style := [fsBold];
  end;
end;

Database-Style Grid

procedure CreateDatabaseStyleGrid(Grid: TTeeGrid);
begin
  // Enable indicator for database-like appearance
  Grid.Indicator.Visible := True;
  Grid.Indicator.Width.Pixels := 16;
  Grid.Indicator.Format.Brush.Color := clBtnFace;
  
  // Enable editing
  Grid.Editing.AutoEdit := True;
  
  // The indicator will automatically show:
  // - Triangle for current row when browsing
  // - Pencil when editing a row
  // - Asterisk when inserting a new row
end;

Coordinating with Selection

procedure SetupGridWithIndicatorAndSelection(Grid: TTeeGrid);
begin
  // Configure indicator
  Grid.Indicator.Visible := True;
  Grid.Indicator.Width.Pixels := 18;
  Grid.Indicator.Format.Brush.Color := clInfoBk;
  
  // Configure selection to highlight full rows
  Grid.Selected.FullRow := True;
  Grid.Selected.Format.Brush.Color := clHighlight;
  Grid.Selected.Font.Color := clWhite;
  
  // The indicator and selection work together to show:
  // - Which row is current (indicator triangle)
  // - Full row highlighting (selection)
end;

Integration with Grid Operations

The indicator automatically updates its display based on grid operations:

Browse Mode

When navigating through rows without editing:

• Shows a triangle (▶) pointing to the current row
• Updates automatically as selection changes

Edit Mode

When editing begins (double-click, F2, or AutoEdit):

• Indicator changes to show a pencil icon
• Indicates the row is in edit mode

Insert Mode

When inserting a new row (for data-bound grids):

• Indicator shows an asterisk (*)
• Indicates a new row being added

Design Patterns

Spreadsheet-Style Grid

procedure ConfigureSpreadsheetStyle(Grid: TTeeGrid);
begin
  Grid.Indicator.Visible := False;  // No indicator in spreadsheets
  Grid.Selected.FullRow := False;   // Cell-level selection
  Grid.Editing.AutoEdit := True;
end;

Database Grid Style

procedure ConfigureDatabaseStyle(Grid: TTeeGrid);
begin
  Grid.Indicator.Visible := True;   // Show row indicator
  Grid.Indicator.Width.Pixels := 16;
  Grid.Selected.FullRow := True;    // Full row selection
  Grid.Editing.DoubleClick := True;
end;

Report/Read-Only Style

procedure ConfigureReportStyle(Grid: TTeeGrid);
begin
  Grid.Indicator.Visible := False;  // No indicator needed
  Grid.ReadOnly := True;            // No editing
  Grid.Selected.Format.Brush.Color := clSilver;
end;

Important Notes

The indicator column is always positioned as the leftmost column in the grid and cannot be moved or reordered.

The indicator width should be kept relatively small (10-20 pixels) to maximize space for data columns.

The indicator state (Browse, Edit, Insert) is managed internally by the grid and should not be modified directly. It updates automatically based on grid operations.

Properties Summary Table

Property	Type	Default	Description
Visible	Boolean	-	Controls indicator visibility
Width	TColumnWidth	10 pixels	Width of the indicator column
Format	TFormat	-	Visual formatting (brush, stroke)
Font	TFont	-	Font for indicator symbols

State Symbols Reference

State	Symbol	Meaning
Browse	▶	Current row in browse mode
Edit	✎	Row is being edited
Insert	*	New row being inserted

See Also

• TGridSelection - Cell selection management
• TGridEditing - Cell editing configuration
• TGridBands - Grid bands for headers and footers
• TColumn - Column configuration