自定义事件实现不同窗体间的通讯Delphi篇

要实现子窗体与父窗体之间的通讯有多种方法（比如重载子窗体的构造函数将父窗体的引用作为参数传递给子窗体）下面我要介绍的是利用自定义事件的方法它能够最大程度的避免模块之间的耦合充分体现面向对象的优点

先将效果图展示给大家

[[The No Picture]]

下面是实现代码

Unit //子窗体

type

//声明自定义事件的类型（类似于C#中的委托）

TMyEventHandle = procedure (Sender: TObject; Content: string) of object;

TForm = class(TForm)

ComboBox: TComboBox;

Label: TLabel;

procedure ComboBoxClick(Sender: TObject);

private

FOnSelectionChanged: TMyEventHandle;

public

//声明自定义事件

property OnSelectionChanged: TMyEventHandle

read FOnSelectionChanged write FOnSelectionChanged;

end;

procedure TFormComboBoxClick(Sender: TObject);

begin

//当选择改变时触发自定义的事件

if Assigned(FOnSelectionChanged) then

FOnSelectionChanged(Self ComboBoxText);

end;

Unit //父窗体

type

TForm = class(TForm)

btnOpenForm: TButton;

Edit: TEdit;

Label: TLabel;

procedure btnOpenFormClick(Sender: TObject);

private

m_frm: TForm;

procedure frm_SelectionChanged(Sender: TObject; Content: string);

public

constructor Create(AOwner: TComponent); override;

destructor Destroy; override;

end;

constructor TFormCreate(AOwner: TComponent);

begin

inherited Create(AOwner);

m_frm := TFormCreate(Self);

//指定当m_frm的自定义事件发生时的处理程序

m_frmOnSelectionChanged := frm_SelectionChanged;

end;

destructor TFormDestroy;

begin

m_frmFree;

inherited Destroy;

end;

procedure TFormfrm_SelectionChanged(Sender: TObject; Content: string);

begin

EditText := Content;

end;

procedure TFormbtnOpenFormClick(Sender: TObject);

begin

m_frmShowModal;

end;