能否在控件之间进行实时绑定,比如将2个编辑框的内容相加并显示在标签中。我相信这是可能的,只是不知道从何处开始。
谢谢
能否在控件之间进行实时绑定,比如将2个编辑框的内容相加并显示在标签中。我相信这是可能的,只是不知道从何处开始。
谢谢
object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 286
ClientWidth = 426
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object Label1: TLabel
Left = 8
Top = 62
Width = 48
Height = 13
Caption = 'Edit1Edit2'
end
object Edit1: TEdit
Left = 8
Top = 8
Width = 121
Height = 21
TabOrder = 0
Text = 'Edit1'
OnChange = EditChange
end
object Edit2: TEdit
Left = 8
Top = 35
Width = 121
Height = 21
TabOrder = 1
Text = 'Edit2'
OnChange = EditChange
end
object BindingsList1: TBindingsList
Methods = <>
OutputConverters = <>
UseAppManager = True
Left = 20
Top = 5
object BindExpressionLabel11: TBindExpression
Category = 'Binding Expressions'
ControlComponent = Label1
SourceComponent = BindScope1
SourceExpression = 'Edit1.Text + Edit2.Text'
ControlExpression = 'Caption'
NotifyOutputs = False
Direction = dirSourceToControl
end
end
object BindScope1: TBindScope
Left = 192
Top = 16
end
end
----- Unit1.pas -----
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Data.Bind.EngExt, Vcl.Bind.DBEngExt,
System.Rtti, System.Bindings.Outputs, Vcl.Bind.Editors, Data.Bind.Components,
Vcl.StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Label1: TLabel;
BindingsList1: TBindingsList;
BindExpressionLabel11: TBindExpression;
BindScope1: TBindScope;
procedure EditChange(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses
System.Bindings.Helper;
procedure TForm1.EditChange(Sender: TObject);
begin
TBindings.Notify(Sender, 'Text');
end;
end.
如何使用IDE设计器来实现以下结果:
这个示例项目位于(默认)位置:
C:\Users\Public\Documents\RAD Studio\9.0\Samples\Delphi\LiveBinding\Components\bindexpression\fmx\BindExpressionSampleProject.dproj
确切地做到这一点。
你不需要使用TBindScope将组件绑定在一起。假设在表单上有edit1和edit2两个控件。如果你将edit2的BindingSource设置为edit1,那么当edit1发生更改时,它也会被应用到edit2中。
SourceExpression = 'Edit1.Text + Edit2.Text'
是如何编译、评估或执行的? - David Heffernan