调用接口的问题,我的com实现了两个接口Iservermodule﹐MyInterface﹐我通过socketconnection1.AppServer调用函数﹐只能调用Iservermodule

Question

我想转换接口但是出现access violate 的错误
var
   t: Olevariant;
   myi: MyInterface;
   i: integer;
begin
   myi:= MyInterface(IDispatch(socketconnection1.AppServer));
   myi.sendretparam(t,i);
   showmessage(t);
end;我想调用queryinterface﹐但出现这样的错误
[Error] Unit1.pas(87): Type not allowed in Variant Dispatch callvar
   t: Olevariant;
   myi: MyInterface;
   i: integer;
begin
   myi:= socketconnection1.AppServer.queryinterface(IID_MyInterface,MyInterface);
   myi.sendretparam(t,i);
   showmessage(t);
end;

Answer 1

socketconnection1.Connected:= false;
socketconnection1.ServerName:= MyInterface;
socketconnection1.Connected:= true;
socketconnection1.AppServer.queryinterface不知道是不是这个意思

Answer 2

回复人： lihao_ningxia(耗子) 
你說什么聲明??

Answer 3

TSocketconnection 不能这样调用.你可以从TSocketconnection源码看出来,它只是实现IDispatch方式的分派调用,
它没有实现对远程对象的查询接口.因为是远程调用,用强制接口转换更没有成功可能.

Answer 4

halfdream(哈欠):怎么樣能解決這樣的問題呢

Answer 5

這是我的接口單元
unit server_TLB;{$TYPEDADDRESS OFF} // Unit must be compiled without type-checked pointers. 
{$WARN SYMBOL_PLATFORM OFF}
{$WRITEABLECONST ON}interfaceuses ActiveX, Classes, Graphics, Midas, StdVCL, Variants, Windows;
  
// *********************************************************************//
// 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
  serverMajorVersion = 1;
  serverMinorVersion = 0;  LIBID_server: TGUID = '{DE154303-0D86-4F49-B734-4E44F3A138A5}';  IID_Iservermodule: TGUID = '{3BB6C61B-1920-4F82-9841-9286CFAA17EA}';
  IID_MyInterface: TGUID = '{B6880ABC-15DF-4CCB-B616-721FAC4949FB}';
  CLASS_servermodule: TGUID = '{BA33845C-8421-4367-9385-B48108ED6FDE}';
type// *********************************************************************//
// Forward declaration of types defined in TypeLibrary                    
// *********************************************************************//
  Iservermodule = interface;
  IservermoduleDisp = dispinterface;
  MyInterface = interface;
  MyInterfaceDisp = dispinterface;// *********************************************************************//
// Declaration of CoClasses defined in Type Library                       
// (NOTE: Here we map each CoClass to its Default Interface)              
// *********************************************************************//
  servermodule = Iservermodule;
// *********************************************************************//
// Interface: Iservermodule
// Flags:     (4416) Dual OleAutomation Dispatchable
// GUID:      {3BB6C61B-1920-4F82-9841-9286CFAA17EA}
// *********************************************************************//
  Iservermodule = interface(IAppServer)
    ['{3BB6C61B-1920-4F82-9841-9286CFAA17EA}']
    function  GetTableNames: OleVariant; safecall;
    function  ExecStoredproc(const storedprocName: WideString; const parameters: WideString): OleVariant; safecall;
  end;// *********************************************************************//
// DispIntf:  IservermoduleDisp
// Flags:     (4416) Dual OleAutomation Dispatchable
// GUID:      {3BB6C61B-1920-4F82-9841-9286CFAA17EA}
// *********************************************************************//
  IservermoduleDisp = dispinterface
    ['{3BB6C61B-1920-4F82-9841-9286CFAA17EA}']
    function  GetTableNames: OleVariant; dispid 1;
    function  ExecStoredproc(const storedprocName: WideString; const parameters: WideString): OleVariant; dispid 2;
    function  AS_ApplyUpdates(const ProviderName: WideString; Delta: OleVariant; 
                              MaxErrors: Integer; out ErrorCount: Integer; var OwnerData: OleVariant): OleVariant; dispid 20000000;
    function  AS_GetRecords(const ProviderName: WideString; Count: Integer; out RecsOut: Integer; 
                            Options: Integer; const CommandText: WideString; 
                            var Params: OleVariant; var OwnerData: OleVariant): OleVariant; dispid 20000001;
    function  AS_DataRequest(const ProviderName: WideString; Data: OleVariant): OleVariant; dispid 20000002;
    function  AS_GetProviderNames: OleVariant; dispid 20000003;
    function  AS_GetParams(const ProviderName: WideString; var OwnerData: OleVariant): OleVariant; dispid 20000004;
    function  AS_RowRequest(const ProviderName: WideString; Row: OleVariant; RequestType: Integer; 
                            var OwnerData: OleVariant): OleVariant; dispid 20000005;
    procedure AS_Execute(const ProviderName: WideString; const CommandText: WideString; 
                         var Params: OleVariant; var OwnerData: OleVariant); dispid 20000006;
  end;// *********************************************************************//
// Interface: MyInterface
// Flags:     (4416) Dual OleAutomation Dispatchable
// GUID:      {B6880ABC-15DF-4CCB-B616-721FAC4949FB}
// *********************************************************************//
  MyInterface = interface(IAppServer)
    ['{B6880ABC-15DF-4CCB-B616-721FAC4949FB}']
    procedure sendretparam(var tt: OleVariant; Param2: Integer); safecall;
  end;// *********************************************************************//
// DispIntf:  MyInterfaceDisp
// Flags:     (4416) Dual OleAutomation Dispatchable
// GUID:      {B6880ABC-15DF-4CCB-B616-721FAC4949FB}
// *********************************************************************//
  MyInterfaceDisp = dispinterface
    ['{B6880ABC-15DF-4CCB-B616-721FAC4949FB}']
    procedure sendretparam(var tt: OleVariant; Param2: Integer); dispid 3;
    function  AS_ApplyUpdates(const ProviderName: WideString; Delta: OleVariant; 
                              MaxErrors: Integer; out ErrorCount: Integer; var OwnerData: OleVariant): OleVariant; dispid 20000000;
    function  AS_GetRecords(const ProviderName: WideString; Count: Integer; out RecsOut: Integer; 
                            Options: Integer; const CommandText: WideString; 
                            var Params: OleVariant; var OwnerData: OleVariant): OleVariant; dispid 20000001;
    function  AS_DataRequest(const ProviderName: WideString; Data: OleVariant): OleVariant; dispid 20000002;
    function  AS_GetProviderNames: OleVariant; dispid 20000003;
    function  AS_GetParams(const ProviderName: WideString; var OwnerData: OleVariant): OleVariant; dispid 20000004;
    function  AS_RowRequest(const ProviderName: WideString; Row: OleVariant; RequestType: Integer; 
                            var OwnerData: OleVariant): OleVariant; dispid 20000005;
    procedure AS_Execute(const ProviderName: WideString; const CommandText: WideString; 
                         var Params: OleVariant; var OwnerData: OleVariant); dispid 20000006;
  end;// *********************************************************************//
// The Class Coservermodule provides a Create and CreateRemote method to          
// create instances of the default interface Iservermodule exposed by              
// the CoClass servermodule. The functions are intended to be used by             
// clients wishing to automate the CoClass objects exposed by the         
// server of this typelibrary.                                            
// *********************************************************************//
  Coservermodule = class
    class function Create: Iservermodule;
    class function CreateRemote(const MachineName: string): Iservermodule;
  end;implementationuses ComObj;class function Coservermodule.Create: Iservermodule;
begin
  Result := CreateComObject(CLASS_servermodule) as Iservermodule;
end;class function Coservermodule.CreateRemote(const MachineName: string): Iservermodule;
begin
  Result := CreateRemoteComObject(MachineName, CLASS_servermodule) as Iservermodule;
end;end.