ToStr()
ToVariant()
Round()
Format()
UpperCase()
LowerCase()
FormatDateTime()
StrToDateTime()
Max()
Min()
CheckedState()
SelectedItem()
SelectedText()

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, Data.Bind.EngExt,
  Fmx.Bind.DBEngExt, Data.Bind.Components;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    BindingsList1: TBindingsList;
    procedure FormCreate(Sender: TObject);
    procedure FormResize(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.FormCreate(Sender: TObject);
begin
  with TBindExpression.Create(BindingsList1) do
  begin
    ControlComponent := Label1;
    ControlExpression := 'Text';
    SourceComponent := Form1;
    SourceExpression := '"宽度: " + ToStr(Width)';
    Active := True;
  end;

  with TBindExpression.Create(BindingsList1) do
  begin
    ControlComponent := Label2;
    ControlExpression := 'Text';
    SourceComponent := Form1;
//    SourceExpression := '"高度: " + ToStr(Height)';
    SourceExpression := 'Format("高度: %s", ToStr(Height))'; //同上一行; 在表达式中使用 Format 函数时, 后面的参数不能放在 [] 中
    Active := True;
  end;

  with TBindExpression.Create(BindingsList1) do
  begin
    ControlComponent := Label3;
    ControlExpression := 'Text';
    SourceComponent := Form1;
    SourceExpression := '"面积: " + ToStr(Width * Height)';
    Active := True;
  end;
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  BindingsList1.Notify(Sender, 'Width');
  BindingsList1.Notify(Sender, 'Height');
end;

end.