> ## 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.

# Array Binding Example

> Display and edit arrays of records, objects, and simple types in TeeGrid

## Overview

TeeGrid can display and edit different kinds of arrays using RTTI (Runtime Type Information). This provides automatic column generation from your data structures.

## Array of Records

The most common use case is displaying an array of records:

```pascal theme={null}
type
  TAddress = record
    Street: String;
    Number: Integer;
  end;

  TPerson = record
    Name: String;
    Address: TAddress;      // Sub-record
    BirthDate: TDateTime;
    Children: Integer;
    IsDeveloper: Boolean;
    Height: Single;
  end;

var
  MyData: TArray<TPerson>;

procedure TFormArray.BRecordClick(Sender: TObject);
begin
  SetLength(MyData, 10);
  FillMyData(MyData);  // Fill with sample data

  // Bind array to grid - automatically creates columns from record fields
  TeeGrid1.Data := TVirtualData<TArray<TPerson>>.Create(MyData);
end;
```

## Array of Simple Types

### Array of Integer

```pascal theme={null}
var
  MyIntegers: TArray<Integer>;

procedure TFormArray.BIntegerClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyIntegers, 100);

  for t := 0 to High(MyIntegers) do
    MyIntegers[t] := Random(1000);

  // Simple syntax
  TeeGrid1.Data := TVirtualArrayData<Integer>.Create(MyIntegers);
  
  // Alternative (equivalent)
  // TeeGrid1.Data := TVirtualData<TArray<Integer>>.Create(MyIntegers);
end;
```

### Array of Float

```pascal theme={null}
var
  MyFloats: TArray<Single>;

procedure TFormArray.BFloatClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyFloats, 200);

  for t := 0 to High(MyFloats) do
    MyFloats[t] := Random(1000) * 0.01;

  TeeGrid1.Data := TVirtualData<TArray<Single>>.Create(MyFloats);
end;
```

### Array of String

```pascal theme={null}
var
  MyStrings: TArray<String>;

procedure TFormArray.BStringClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyStrings, 10);

  for t := 0 to High(MyStrings) do
    MyStrings[t] := 'Item ' + IntToStr(t);

  TeeGrid1.Data := TVirtualData<TArray<String>>.Create(MyStrings);
end;
```

## Array of Objects

```pascal theme={null}
type
  TVehicle = class(TPersistent)
  public
    Brand: String;
  end;

  TCar = class(TVehicle)
  private
    FSpeed: Double;
  public
    Wheels: Word;
    Driver: TPerson;
    property Speed: Double read FSpeed write FSpeed;
  end;

var
  MyCars: TArray<TCar>;

procedure TFormArray.BTObjectClick(Sender: TObject);
begin
  SetLength(MyCars, 10);
  FillMyData(MyCars);  // Create and populate car objects

  TeeGrid1.Data := TVirtualData<TArray<TCar>>.Create(MyCars);
end;
```

<Warning>
  Remember to free object instances in arrays when you're done:

  ```pascal theme={null}
  procedure Clean(const ACars: TArray<TCar>);
  var
    t: Integer;
  begin
    for t := Low(ACars) to High(ACars) do
      ACars[t].Free;
  end;
  ```
</Warning>

## Complete Example from Demos

From `Unit_Array.pas` in the VirtualData demos:

```pascal theme={null}
unit Unit_Array;

interface

uses
  Vcl.Forms, VCLTee.Control, VCLTee.Grid, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TFormArray = class(TForm)
    TeeGrid1: TTeeGrid;
    BInteger: TButton;
    BFloat: TButton;
    BString: TButton;
    BTObject: TButton;
    BRecord: TButton;
    procedure FormCreate(Sender: TObject);
    procedure BIntegerClick(Sender: TObject);
    procedure BFloatClick(Sender: TObject);
    procedure BStringClick(Sender: TObject);
    procedure BRecordClick(Sender: TObject);
    procedure BTObjectClick(Sender: TObject);
  end;

implementation

uses
  Unit_MyData, Tee.GridData, Tee.GridData.Rtti;

var
  MyIntegers: TArray<Integer>;
  MyFloats: TArray<Single>;
  MyStrings: TArray<String>;
  MyData: TArray<TPerson>;
  MyCars: TArray<TCar>;

procedure TFormArray.BIntegerClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyIntegers, 100);
  for t := 0 to High(MyIntegers) do
    MyIntegers[t] := Random(1000);

  TeeGrid1.Data := TVirtualArrayData<Integer>.Create(MyIntegers);
end;

procedure TFormArray.BFloatClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyFloats, 200);
  for t := 0 to High(MyFloats) do
    MyFloats[t] := Random(1000) * 0.01;

  TeeGrid1.Data := TVirtualData<TArray<Single>>.Create(MyFloats);
end;

procedure TFormArray.BStringClick(Sender: TObject);
var
  t: Integer;
begin
  SetLength(MyStrings, 10);
  for t := 0 to High(MyStrings) do
    MyStrings[t] := 'Sample ' + IntToStr(t);

  TeeGrid1.Data := TVirtualData<TArray<String>>.Create(MyStrings);
end;

procedure TFormArray.BRecordClick(Sender: TObject);
begin
  SetLength(MyData, 10);
  FillMyData(MyData);

  TeeGrid1.Data := TVirtualData<TArray<TPerson>>.Create(MyData);
end;

procedure TFormArray.BTObjectClick(Sender: TObject);
begin
  SetLength(MyCars, 10);
  FillMyData(MyCars);

  TeeGrid1.Data := TVirtualData<TArray<TCar>>.Create(MyCars);
end;

procedure TFormArray.FormCreate(Sender: TObject);
begin
  // Start with array of records
  BRecordClick(Self);
  
  // Enable multi-line text in cells
  TeeGrid1.Rows.Height.Automatic := True;
end;

end.
```

## Key Concepts

### Automatic Column Generation

TeeGrid uses RTTI to automatically:

* Detect all public fields and published properties
* Create columns with appropriate editors (string, numeric, date, boolean)
* Handle nested records (creates sub-columns)
* Format data appropriately (dates, floats, etc.)

### Sub-Records

Nested records are automatically expanded:

```pascal theme={null}
TAddress = record
  Street: String;
  Number: Integer;
end;

TPerson = record
  Name: String;
  Address: TAddress;  // Creates "Address.Street" and "Address.Number" columns
end;
```

### Data Formatting

```pascal theme={null}
// Format float columns
TeeGrid1.Columns['Height'].DataFormat.Float := '0.##';

// Format date columns
TeeGrid1.Columns['BirthDate'].DataFormat.DateTime := 'mm-dd-yyyy';
```

## Features Demonstrated

* Array of simple types (Integer, Single, String)
* Array of records with nested structures
* Array of object instances
* Automatic column generation via RTTI
* Custom data formatting

## Next Steps

* Learn about [List Binding](/examples/list-binding) for TList\<T>
* Explore [Custom Editors](/examples/custom-editors) for cell editing
* See [Custom Sorting](/examples/custom-sorting) to enable sorting

## Related Examples

* [List Binding](/examples/list-binding)
* [Dataset Binding](/examples/dataset-binding)
* [Virtual Mode](/examples/virtual-mode)