Documentation Index
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Overview
The TGridBands class is a collection that manages multiple TGridBand objects. Grid bands are rectangular areas within a TeeGrid that can display headers, footers, totals, or custom content. Each band supports mouse interaction, custom height, and click events.
Class Hierarchy
TCollectionChange
└── TGridBands
Properties
Visible
property Visible: Boolean read FVisible write SetVisible default True;
True
Example:
TeeGrid1.Header.Bands.Visible := False; // Hide all header bands
Items
property Items[Index: Integer]: TGridBand read Get write Put; default;
TGridBand objects in the collection.
Parameters:
Index: Zero-based integer index
Example:
var
Band: TGridBand;
begin
Band := TeeGrid1.Header.Bands[0];
Band.Height.Pixels := 40;
end;
Floating
Determines whether bands float over grid content or occupy fixed space.
Height
The total calculated height of all bands in the collection.
Methods
Constructor Create
Constructor Create(AOwner: TPersistent; const AChanged: TNotifyEvent);
TGridBands collection.
Parameters:
AOwner: The persistent object that owns this collectionAChanged: Event handler called when the collection changes
Assign
procedure Assign(Source: TPersistent); override;
Source: The source object to copy from
Example:
TeeGrid2.Header.Bands.Assign(TeeGrid1.Header.Bands);
AddText
function AddText(const AText: String): TTextBand;
AText: The text to display in the band
Returns: The newly created TTextBand object
Example:
var
Band: TTextBand;
begin
Band := TeeGrid1.Header.Bands.AddText('Monthly Report');
Band.Height.Pixels := 30;
Band.TextRender.Font.Size := 14;
Band.TextRender.Font.Style := [fsBold];
end;
CalcHeight
procedure CalcHeight(const APainter: TPainter; const ATotal: Single);
APainter: The painter object used for measurement calculationsATotal: The total available height
CanDisplay
function CanDisplay: Boolean; inline;
True if the band collection can be displayed (is visible and contains items).
Returns: Boolean indicating if bands should be painted
Mouse
procedure Mouse(var AState: TMouseState; const AWidth, AHeight: Single);
AState: The current mouse state (position, button, event type)AWidth: The width of the band areaAHeight: The height of the band area
Paint
procedure Paint(var AData: TRenderData);
AData: Rendering data containing painter and bounds information
TGridBand
Base class for individual bands with the following key properties:
- Height:
TBandHeight - The height of the band
- OnClick:
TNotifyEvent - Event triggered when the band is clicked
- Visible:
Boolean - Controls band visibility
- Hover: Inherited hover support for mouse interaction
TTextBand
Specialized band for displaying text, inherits from TGridBand:
- Text:
String - The text to display
- TextRender:
TCellRender - Formatting options for the text
Usage Examples
procedure SetupCustomHeader(Grid: TTeeGrid);
var
TitleBand: TTextBand;
begin
Grid.Headers.Visible := True;
// Add title band
TitleBand := Grid.Headers.AddText('Sales Dashboard');
TitleBand.Height.Pixels := 40;
TitleBand.TextRender.Font.Size := 16;
TitleBand.TextRender.Font.Style := [fsBold];
TitleBand.Format.Brush.Color := clNavy;
TitleBand.TextRender.Font.Color := clWhite;
end;
Adding Multiple Bands
procedure AddMultipleBands(Grid: TTeeGrid);
var
Band1, Band2: TTextBand;
begin
// Add header bands
Band1 := Grid.Headers.AddText('Company Name');
Band1.Height.Pixels := 30;
Band2 := Grid.Headers.AddText('Report Date: ' + DateToStr(Now));
Band2.Height.Pixels := 25;
Band2.TextRender.Font.Size := 10;
end;
Handling Band Click Events
procedure TForm1.CreateBandWithClick;
var
Band: TTextBand;
begin
Band := TeeGrid1.Headers.AddText('Click Me');
Band.OnClick := BandClickHandler;
end;
procedure TForm1.BandClickHandler(Sender: TObject);
begin
ShowMessage('Band clicked!');
end;
Constants
Spacing
The spacing between bands (currently fixed at 0 pixels).
See Also
