我有一个界面.
type IProgressObserver = interface(IInterface) procedure ReportProgress(Progress:Integer); procedure ReportError(Message:string); end;@H_301_3@我使用命名类实现了接口,如下所示:
type TProgressObserver=class(TInterfacedObject,IProgressObserver) procedure ReportProgress(Progress:Integer); procedure ReportError(Message:string); end; ... implementation of methods go here ..... addProgressObserver(TProgressObserver.Create);@H_301_3@是否可以在不声明类的情况下创建此接口的实例?像这个(虚构的)代码,它会做与上面相同的事情:
addProgressObserver(IProgressObserver.Create() begin procedure ReportProgress(Progress:Integer) begin ShowMessage('Progress Observed!'); end procedure ReportError(Message:string) begin Log(Message); end end;);@H_301_3@Delphi有匿名程序,但是它有匿名类吗?
我找到了this similar question,但它是用Java编写的.
我正在使用Delphi 2010
解决方法
你可以匿名,使用匿名方法实现接口.但是你没有得到实际的编译器支持,你必须自己声明所有的匿名方法类型,然后实现实际的“匿名”类.给定您的IProgressObserver接口,实现看起来像这样:
type // This is the interface we'll be dealing with. IProgressObserver = interface(IInterface) procedure ReportProgress(Progress:Integer); procedure ReportError(Message:string); end; // This will help us anonymously create implementations of the IProgressObserver // interface. TAnonymousObserverImp = class(TInterfacedObject,IProgressObserver) type // Declare reference types for all the methods the interface needs. TReportProgressProc = reference to procedure(Progress:Integer); TReportErrorProc = reference to procedure(Message:string); strict private FReportProgressProc: TReportProgressProc; FReportErrorProc: TReportErrorProc; // Actual implementation of interface methods. procedure ReportProgress(Progress:Integer); procedure ReportError(Message:string); // private constructor,so we'll forced to use the public "Construct" function constructor Create(aReportProgressProc: TReportProgressProc; aReportErrorProc: TReportErrorProc); public // This takes the required anonymous methods as parameters and constructs an anonymous implementation // of the IProgressObserver interface. class function Construct(aReportProgressProc: TReportProgressProc; aReportErrorProc: TReportErrorProc): IProgressObserver; end; { TAnonymousObserverImp } class function TAnonymousObserverImp.Construct( aReportProgressProc: TReportProgressProc; aReportErrorProc: TReportErrorProc): IProgressObserver; begin // Call the private constructor Result := TAnonymousObserverImp.Create(aReportProgressProc,aReportErrorProc); end; constructor TAnonymousObserverImp.Create( aReportProgressProc: TReportProgressProc; aReportErrorProc: TReportErrorProc); begin inherited Create; // We simply save the references for later use FReportProgressProc := aReportProgressProc; FReportErrorProc := aReportErrorProc; end; procedure TAnonymousObserverImp.ReportError(Message: string); begin // Delegate to anonymous method FReportErrorProc(Message); end; procedure TAnonymousObserverImp.ReportProgress(Progress: Integer); begin // Delegate to anonymous method FReportProgressProc(Progress); end;@H_301_3@var i: IProgressObserver; begin i := TAnonymousObserverImp.Construct( procedure (Progress:Integer) begin // Do something with Progress end,procedure (Message:string) begin // Do something with Message end ) end;@H_301_3@