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
TeeGrid1.Indicator.Visible := True;
Width
property Width: TColumnWidth read FWidth write SetWidth;
DefaultWidth (10 pixels)
Example:
TeeGrid1.Indicator.Width.Pixels := 20;
property Format: TFormat; // Inherited from TVisibleTextRender
TeeGrid1.Indicator.Format.Brush.Color := clLightBlue;
TeeGrid1.Indicator.Format.Stroke.Color := clBlue;
Font
property Font: TFont; // Inherited from TVisibleTextRender
TeeGrid1.Indicator.Font.Color := clNavy;
TeeGrid1.Indicator.Font.Size := 10;
Constants
DefaultWidth
The default width of the indicator column in pixels.
Methods
Constructor Create
Constructor Create(const AChanged: TNotifyEvent); override;
TIndicator instance.
Parameters:
AChanged: Event handler called when indicator properties change
Assign
procedure Assign(Source: TPersistent); override;
Source: The source object to copy from
Example:
TeeGrid2.Indicator.Assign(TeeGrid1.Indicator);
Paint
procedure Paint(var AData: TRenderData); override;
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
