> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/Steema/TeeGrid-VCL-FMX-Samples/llms.txt
> Use this file to discover all available pages before exploring further.

# TGridBands

> Collection class for managing grid bands - rectangular areas that display at headers, footers, or custom positions

## 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

```pascal theme={null}
property Visible: Boolean read FVisible write SetVisible default True;
```

Controls whether the band collection is visible in the grid.

**Default**: `True`

**Example**:

```pascal theme={null}
TeeGrid1.Header.Bands.Visible := False; // Hide all header bands
```

### Items

```pascal theme={null}
property Items[Index: Integer]: TGridBand read Get write Put; default;
```

Provides indexed access to individual `TGridBand` objects in the collection.

**Parameters**:

* `Index`: Zero-based integer index

**Example**:

```pascal theme={null}
var
  Band: TGridBand;
begin
  Band := TeeGrid1.Header.Bands[0];
  Band.Height.Pixels := 40;
end;
```

### Floating

```pascal theme={null}
var Floating: Boolean;
```

Determines whether bands float over grid content or occupy fixed space.

### Height

```pascal theme={null}
var Height: Single;
```

The total calculated height of all bands in the collection.

## Methods

### Constructor Create

```pascal theme={null}
Constructor Create(AOwner: TPersistent; const AChanged: TNotifyEvent);
```

Creates a new `TGridBands` collection.

**Parameters**:

* `AOwner`: The persistent object that owns this collection
* `AChanged`: Event handler called when the collection changes

### Assign

```pascal theme={null}
procedure Assign(Source: TPersistent); override;
```

Copies properties from another persistent object.

**Parameters**:

* `Source`: The source object to copy from

**Example**:

```pascal theme={null}
TeeGrid2.Header.Bands.Assign(TeeGrid1.Header.Bands);
```

### AddText

```pascal theme={null}
function AddText(const AText: String): TTextBand;
```

Adds a new text band to the collection with the specified text.

**Parameters**:

* `AText`: The text to display in the band

**Returns**: The newly created `TTextBand` object

**Example**:

```pascal theme={null}
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

```pascal theme={null}
procedure CalcHeight(const APainter: TPainter; const ATotal: Single);
```

Calculates the total height required for all bands in the collection.

**Parameters**:

* `APainter`: The painter object used for measurement calculations
* `ATotal`: The total available height

### CanDisplay

```pascal theme={null}
function CanDisplay: Boolean; inline;
```

Returns `True` if the band collection can be displayed (is visible and contains items).

**Returns**: Boolean indicating if bands should be painted

### Mouse

```pascal theme={null}
procedure Mouse(var AState: TMouseState; const AWidth, AHeight: Single);
```

Handles mouse events for all bands in the collection.

**Parameters**:

* `AState`: The current mouse state (position, button, event type)
* `AWidth`: The width of the band area
* `AHeight`: The height of the band area

### Paint

```pascal theme={null}
procedure Paint(var AData: TRenderData);
```

Paints all visible bands in the collection.

**Parameters**:

* `AData`: Rendering data containing painter and bounds information

## Related Classes

### 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

### Creating a Custom Header

```pascal theme={null}
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

```pascal theme={null}
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

```pascal theme={null}
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

```pascal theme={null}
const Spacing = 0;
```

The spacing between bands (currently fixed at 0 pixels).

## See Also

* [TGridSelection](/api/tgridselection) - Cell selection management
* [TGridEditing](/api/tgridediting) - Cell editing configuration
* [TIndicator](/api/tindicator) - Grid row indicator column