获取对IDispatch接口成员的访问权限

Question

我是个物理学家。我正在尝试用一个导入的activex控件(ocx文件)在Delphi上工作。假设库中有3个自动化接口: IGraph、IGraphAxes和IAxis。库的结构是这样的：

=IGraph的properties:===

Idispatch* IGraphAxes；

... //其他成员

===IGraphAxes的properties:===

Idispatch* XAxis；

Idispatch* YAxis；

Idispatch* ZAxis；

整型颜色；

整型风格；

…//其他成员

===IAxis properties:===

浮点最小，最大；

布尔ShowNumbers；

…//其他成员

在IGraph中，我可以使用GetIDsOfNames()和Invoke()函数访问IGraphAxes (颜色和样式)的简单成员。但是，当我尝试访问XAxis (或YAxis，Zaxis)时，它会产生一个错误。首先，我使用GetIDsOfNames()，它返回XAxis的调度it，没有任何问题。但是，当我使用该调度I调用Invoke时，出现错误“Access violation at address…”。看起来，idispatch指针(**X轴)*没有指向任何内容。我该如何解决这个问题呢？如何制作

Idispatch* Xaxis

和

IAxis接口是否相互连接？

另外，对不起我的英语，我不是以英语为母语的人。

Answer 1

Delphi内置了对Invoke后期绑定的支持，因此您不需要直接调用IDispatch ()。只需像访问普通属性一样访问成员，Delphi将在幕后为您调用Invoke()。

如果您想直接调用Invoke()，请显示实际失败的代码。AV很可能是由于代码中的错误，而不是OCX本身。

Answer 2

感谢您的回复。实际上，activex控件是用于绘制某些3d图形的第三方可视化组件。下面是activex库的内容：

uuid(...)，

版本(x.x)，

helpstring(“三维图形模块”)，

控制，

自定义(...，...)，

自定义(...，...)

库GraphLib

{

importlib(“stdoe2.tlb”)；

uuid(...)，

helpstring(“3D图形控制调度接口”)，

隐藏

显示接口_IGraph

{

属性：

id(0x0000006)

IDispatch * GraphAxes(...)；

方法：

id(0x0000001)

byte AddScatterGraph(...)；

id(0x0000002)

byte AddVectorFieldGraph(...)；

id(0x0000003)

byte AddParametricSurfaceGraph(...)；

id(0x0000004)

byte AddSurfaceGraph(...)；

id(0x0000005)

字节RemoveGraphs(空)；

}；

uuid(...)，

helpstring(“三维图形控件”)，

控制

coclass cGraph

{

默认显示接口_IGraph；

默认值，源调度接口_IGraphEvents；

}；

uuid(...)

显示接口IGraphAxis

{

属性：

id(0x00000001)

字节编号；

id(0x00000002)

double Min；

id(0x00000003)

双倍最大值；

id(0x00000004)

short GridNum；

id(0x00000005)

字节ShowLabel；

方法：

}；

uuid(...)

coclass cGraphAxis

{

默认显示接口IGraphAxis；

}；

uuid(...)

显示接口IGraphAxes

{

属性：

id(0x00000001)

IDispatch * XAxis；

id(0x00000002)

IDispatch * YAxis；

id(0x00000003)

IDispatch * ZAxis；

id(0x00000004)

整型颜色；

id(0x00000005)

整型风格；

方法：

}；

uuid(...)

coclass cGraphAxes

{

默认显示接口IGraphAxes；

}；

uuid(...)，

helpstring(“三维图形控件的事件接口”)

显示接口_IGraphEvents

{

属性：

方法：

id(0xFFFFFDA3)

无效MouseDown(…)；

id(0xFFFFFDA8)

void单击…)；

id(0xFFFFFDA7)

无效DblClick(…)；

id(0xFFFFFDA6)

无效KeyDown(…)；

id(0xFFFFFDA5)

无效KeyPress(…)；

id(0xFFFFFDA4)

无效KeyUp(…)；

id(0xFFFFFDA2)

无效MouseMove(…)；

id(0xFFFFFDA1)

无效MouseUp(…)；

}；

};

Answer 3

下面是从类型库生成的单元文件。

单元GraphLib_TLB；

// ************************************************************************  
// The types declared in this file were generated from data read from a       
// Type Library. If this type library is explicitly or indirectly (via        
// another type library referring to this type library) re-imported, or the   
// 'Refresh' command of the Type Library Editor activated while editing the   
// Type Library, the contents of this file will be regenerated and all        
// manual modifications will be lost.                                         
// ************************************************************************ //

// ************************************************************************  //  
// Type Lib: graph3d.ocx (1)  
// LIBID: {...}  
// LCID: 0  
// HelpString: 3-D Graph module  
// DepndLst:   
//   (1) v2.0 stdole, (C:\Windows\system32\stdole2.tlb)  
// ************************************************************************ //  
{$TYPEDADDRESS OFF} // Unit must be compiled without type-checked pointers.   
{$WARN SYMBOL_PLATFORM OFF}  
{$WRITEABLECONST ON}  
{$VARPROPSETTER ON}  
interface  

uses Windows, ActiveX, Classes, Graphics, OleCtrls, OleServer, StdVCL, Variants;  

// *********************************************************************//  
// GUIDS declared in the TypeLibrary. Following prefixes are used:        
//   Type Libraries     : LIBID_xxxx                                      
//   CoClasses          : CLASS_xxxx                                      
//   DISPInterfaces     : DIID_xxxx                                       
//   Non-DISP interfaces: IID_xxxx                                        
// *********************************************************************//  
const  
  // TypeLibrary Major and minor versions  
  GraphLibMajorVersion = x;  
  GraphLibMinorVersion = x;  

  LIBID_GLLib: TGUID = '{...}';  

  DIID__IGraph: TGUID = '{...}';  
  DIID__IGraphEvents: TGUID = '{...}';  
  CLASS_cGraph: TGUID = '{...}';  
  DIID_IGraphAxis: TGUID = '{...}';  
  CLASS_cGraphAxis: TGUID = '{...}';  
  DIID_IGraphAxes: TGUID = '{...}';  
  CLASS_cGraphAxes: TGUID = '{...}';  
type  

// *********************************************************************//  
// Forward declaration of types defined in TypeLibrary                      
// *********************************************************************//  
  _IGraph = dispinterface;  
  _IGraphEvents = dispinterface;  
  IGraphAxis = dispinterface;   
  IGraphAxes = dispinterface;  
// *********************************************************************//  
// Declaration of CoClasses defined in Type Library                         
// (NOTE: Here we map each CoClass to its Default Interface)                
// *********************************************************************//  
  cGraph = _IGraph;  
  cGraphAxis = IGraphAxis;  
  cGraphAxes = IGraphAxes;  

// *********************************************************************//  
// Declaration of structures, unions and aliases.                           
// *********************************************************************//  
  PWideString1 = ^WideString; {*}  
  PShortint1 = ^Shortint; {*}  
  PSmallint1 = ^Smallint; {*}  

// *********************************************************************//  
// DispIntf:  _IGraph  
// Flags:     (4112) Hidden Dispatchable  
// GUID:      {...}  
// *********************************************************************//  
  _IGraph = dispinterface  
    ['{...}']  
    function AddScatterGraph(...): {??Shortint}OleVariant; dispid 1;  
    function AddVectorFieldGraph(...): {??Shortint}OleVariant; dispid 2;  
    function AddParametricSurfaceGraph(...): {??Shortint}OleVariant; dispid 3;  
    function AddSurfaceGraph(...): {??Shortint}OleVariant; dispid 4;  
    function RemoveGraphs: {??Shortint}OleVariant; dispid 5;  
    property GraphAxes: IDispatch dispid 6;  
  end;  

// *********************************************************************//  
// DispIntf:  _IGraphEvents  
// Flags:     (4096) Dispatchable  
// GUID:      {...}  
// *********************************************************************//  
  _IGraphEvents = dispinterface  
    ['{...}']  
    procedure MouseDown(); dispid -605;  
    procedure Click; dispid -600;  
    procedure DblClick; dispid -601;  
    procedure KeyDown(...); dispid -602;  
    procedure KeyPress(...); dispid -603;  
    procedure KeyUp(...); dispid -604;  
    procedure MouseMove(...); dispid -606;  
    procedure MouseUp(...); dispid -607;  
    procedure ReadyStateChange; dispid -609;  
  end;  

// *********************************************************************//  
// DispIntf:  IGraphAxis  
// Flags:     (4096) Dispatchable  
// GUID:      {...}  
// *********************************************************************//  
  IGraphAxis = dispinterface  
    ['{...}']  
    property Numbered: {??Shortint}OleVariant dispid 1;  
    property Min: Double dispid 2;  
    property Max: Double dispid 3;  
    property GridNum: Smallint dispid 4;  
    property ShowLabel: {??Shortint}OleVariant dispid 5;        
  end;  

// *********************************************************************//  
// DispIntf:  IGraphAxes  
// Flags:     (4096) Dispatchable  
// GUID:      {...}  
// *********************************************************************//  
  IGraphAxes = dispinterface  
    ['{...}']  
    property XAxis: IDispatch dispid 1;  
    property YAxis: IDispatch dispid 2;  
    property ZAxis: IDispatch dispid 3;  
    property Color: Integer dispid 4;  
    property Style: Smallint dispid 5;  
  end;  

// *********************************************************************//  
// OLE Control Proxy class declaration  
// Control Name     : TGraph  
// Help String      : 3-D Graph Control  
// Default Interface: _IGraph  
// Def. Intf. DISP? : Yes  
// Event   Interface: _IGraphEvents  
// TypeFlags        : (34) CanCreate Control  
// *********************************************************************//  
  TGraph = class(TOleControl)  
  private  
    FOnError: TGraphError;  
    FOnReadyStateChange: TNotifyEvent;  
    FIntf: _IGraph;  
    function  GetControlInterface: _IGraph;  
  protected  
    procedure CreateControl;  
    procedure InitControlData; override;  
    function Get_GraphAxes: IDispatch;  
    procedure Set_GraphAxes(const Value: IDispatch);  
  public  
    function AddScatterGraph(...): {??Shortint}OleVariant;  
    function AddVectorFieldGraph(...): {??Shortint}OleVariant;  
    function AddParametricSurfaceGraph(...): {??Shortint}OleVariant;  
    function AddSurfaceGraph(...): {??Shortint}OleVariant;  
    function RemoveGraphs: {??Shortint}OleVariant;  
    property ControlInterface: _IGraph read GetControlInterface;  
    property DefaultInterface: _IGraph read GetControlInterface;  
    property GraphAxes: IDispatch index 6 read GetIDispatchProp write SetIDispatchProp;  
  published  
    //properties visible in the Object Inspector go here   
    ...  
    property  OnDragDrop;  
    property  OnDragOver;  
    property  OnEndDrag;  
    property  OnEnter;  
    property  OnExit;  
    property  OnStartDrag;  
    property  OnMouseUp;  
    property  OnMouseMove;  
    property  OnMouseDown;  
    property  OnKeyUp;  
    property  OnKeyPress;  
    property  OnKeyDown;  
    property  OnDblClick;  
    property  OnClick;  
    property OnError: TGraphError read FOnError write FOnError;  
    property OnReadyStateChange: TNotifyEvent read FOnReadyStateChange write FOnReadyStateChange;    
  end;    

// *********************************************************************//  
// The Class CocGraphAxis provides a Create and CreateRemote method to            
// create instances of the default interface IGraphAxis exposed by                
// the CoClass cGraphAxis. The functions are intended to be used by               
// clients wishing to automate the CoClass objects exposed by the           
// server of this typelibrary.                                              
// *********************************************************************//  
  CocGraphAxis = class  
    class function Create: IGraphAxis;  
    class function CreateRemote(const MachineName: string): IGraphAxis;  
  end;  

// *********************************************************************//  
// The Class CocGraphAxes provides a Create and CreateRemote method to            
// create instances of the default interface IGraphAxes exposed by                
// the CoClass cGraphAxes. The functions are intended to be used by               
// clients wishing to automate the CoClass objects exposed by the           
// server of this typelibrary.                                              
// *********************************************************************//  
  CocGraphAxes = class  
    class function Create: IGraphAxes;  
    class function CreateRemote(const MachineName: string): IGraphAxes;  
  end;  

procedure Register;  

resourcestring  
  dtlServerPage = 'ActiveX';  

  dtlOcxPage = 'ActiveX';  

implementation  

uses ComObj;  

procedure TGraph.InitControlData;  
const  
  CEventDispIDs: array [0..1] of DWORD = (...);  
  CLicenseKey: array[0..33] of Word = ($006F, ..., ..., e.g.);  
  CControlData: TControlData2 = (  
    ClassID: '{...}';  
    EventIID: '{...}';  
    EventCount: 2;  
    EventDispIDs: @CEventDispIDs;  
    LicenseKey: @CLicenseKey;  
    Flags: $00000000;  
    Version: 401);  
begin  
  ControlData := @CControlData;  
  TControlData2(CControlData).FirstEventOfs := Cardinal(@@FOnError) - Cardinal(Self);  
end;  

procedure TGraph.CreateControl;  

  procedure DoCreate;  
  begin  
    FIntf := IUnknown(OleObject) as _IGraph;  
  end;  

begin  
  if FIntf = nil then DoCreate;  
end;  

function TGraph.GetControlInterface: _IGraph;  
begin  
  CreateControl;  
  Result := FIntf;  
end;  

function TGraph.Get_GraphAxes: IDispatch;  
begin  
  Result := DefaultInterface.GraphAxes;  
end;  

procedure TGraph.Set_GraphAxes(const Value: IDispatch);  
begin  
  DefaultInterface.GraphAxes := Value;  
end;  

function TGraph.AddScatterGraph(...): {??Shortint}OleVariant;  
begin  
  Result := DefaultInterface.AddScatterGraph(...);  
end;  

function TGraph.AddVectorFieldGraph(...): {??Shortint}OleVariant;  
begin  
  Result := DefaultInterface.AddVectorFieldGraph(...);  
end;  

function TGraph.AddParametricSurfaceGraph(...): {??Shortint}OleVariant;  
begin  
  Result := DefaultInterface.AddParametricSurfaceGraph(...);  
end;  

function TGraph.AddSurfaceGraph(...): {??Shortint}OleVariant;  
begin  
  Result := DefaultInterface.AddSurfaceGraph(...);  
end;  

function TGraph.RemoveGraphs: {??Shortint}OleVariant;  
begin  
  Result := DefaultInterface.RemoveGraphs;  
end;  

class function CocGraphAxis.Create: IGraphAxis;  
begin  
  Result := CreateComObject(CLASS_cGraphAxis) as IGraphAxis;  
end;  

class function CocGraphAxis.CreateRemote(const MachineName: string): IGraphAxis;  
begin  
  Result := CreateRemoteComObject(MachineName, CLASS_cGraphAxis) as IGraphAxis;  
end;  

class function CocGraphAxes.Create: IGraphAxes;  
begin  
  Result := CreateComObject(CLASS_cGraphAxes) as IGraphAxes;  
end;  

class function CocGraphAxes.CreateRemote(const MachineName: string): IGraphAxes;  
begin  
  Result := CreateRemoteComObject(MachineName, CLASS_cGraphAxes) as IGraphAxes;  
end;  

procedure Register;  
begin  
  RegisterComponents(dtlOcxPage, [TGraph]);  
end;  

end.