接口编组在Delphi [英] Interface Marshalling in Delphi

问题描述

我想将IVApplication的Interface Ref从Visio加载项发送到我的另一个COM服务器。但我有Ole异常。现在我这样做：

Visio加载项中的代码：

  var 
 IStrm：IStream; 
 hres：HResult; 
 rhglobal：HGLOBAL; 
 VisioAppl：IVApplication; 
 begin 
 
 hres：= CreateStreamOnHGlobal（0，TRUE，IStrm）; 
 if Succeeded（hres）then 
 hres：= CoMarshalInterface（IStrm，IID_IVApplication，VisioAppl，
 MSHCTX_LOCAL，0，
 MSHLFLAGS_NORMAL）; 
 if（Succeeded（hres））then 
 begin 
 hres：= GetHGlobalFromStream（IStrm，rhglobal）; 
如果成功（hres）then 
结果：= rhglobal; 
 IStrm：= nil; 
 end; 
 end; 
 

之后，我创建了我的COM服务器的实例，并传递rhglobal给他。

我的COM服务器的代码：

 程序（AHGlobal：HGlobal）; 
 var 
 VisioAppl：Visio_TLB.IVApplication; 
 iStrm：IStream; 
 hres：HResult; 
 begin 
 
 iStrm：= Nil; 
 VisioAppl：= nil; 
 hres：= CreateStreamOnHGlobal（AHGlobal，FALSE，iStrm）; 
 if（SUCCEEDED（hres））then 
 begin 
 
 hres：= CoUnmarshalInterface（iStrm，Visio_TLB.IVApplication，VisioAppl）; 
 iStrm：= nil; 
 ShowMessage（'Result：'+ BoolToStr（SUCCEEDED（hres）））; <  -  result 0 
 ShowMessage（VisioAppl.ProductName）; < ----错误
 end; 
 
 end; 
  

解决方案

COM服务器并创建一个VARIANT参数？ （或IDispatch *或IUknown *）。

然后，您可以将VisioApplication传递到COM服务器，并在服务器端将其转换回Visio_TLB.IVApplication接口。 / p>

因此，它将如下所示：

Addin：

 过程SendAppToComServer（aIntf：Visio_TLB.IVApplication）; 
 begin 
 MyComServer.PassVisioApp（aIntf）; 
 end; 
  

Comserver：

 code> procedure TMyComServer.PassVisioApp（VisioApp：OleVariant）; 
 var 
 VisioAppIntf：Visio_TLB.IVApplication; 
 begin 
 VisioAppIntf：= VisioApp; 
 ShowMessage（VisioAppIntf.ProductName）; 
 end; 
  

I want to send Interface Ref of IVApplication from Visio Add-in to my other one COM server. But I have Ole exception. Now i do that:

Code in Visio Add-in:

var 
  IStrm: IStream;
  hres: HResult;
  rhglobal: HGLOBAL;
  VisioAppl: IVApplication; 
begin

   hres := CreateStreamOnHGlobal(0, TRUE, IStrm);
      if Succeeded(hres) then
        hres := CoMarshalInterface(IStrm, IID_IVApplication, VisioAppl,
                            MSHCTX_LOCAL, 0,
                            MSHLFLAGS_NORMAL);
      if (Succeeded(hres)) then
      begin
          hres := GetHGlobalFromStream(IStrm, rhglobal);
          if Succeeded(hres)  then
             Result := rhglobal;
          IStrm := nil;
      end;
 end;

After this I create instance of my COM server and pass rhglobal to him.

Code of my COM server:

procedure (AHGlobal: HGlobal);
var
  VisioAppl: Visio_TLB.IVApplication;
  iStrm: IStream;
  hres: HResult;
begin

      iStrm := Nil;
      VisioAppl:= nil;
      hres := CreateStreamOnHGlobal(AHGlobal, FALSE, iStrm);
      if (SUCCEEDED(hres)) then
      begin

        hres := CoUnmarshalInterface(iStrm, Visio_TLB.IVApplication, VisioAppl);
        iStrm := nil;
        ShowMessage('Result:' + BoolToStr(SUCCEEDED(hres)));  <-- result 0 
        ShowMessage(VisioAppl.ProductName); <----  Error
      end;

end;

解决方案

Why don't you just define a method in your COM server and make a VARIANT parameter? (or IDispatch* or IUknown*).

Then you can just pass the VisioApplication to your COM server and at the serverside cast it back to the Visio_TLB.IVApplication interface.

So it will look like this:

Addin:

procedure SendAppToComServer(aIntf: Visio_TLB.IVApplication);
begin
  MyComServer.PassVisioApp(aIntf);
end;

Comserver:

procedure TMyComServer.PassVisioApp(VisioApp: OleVariant);
var
  VisioAppIntf: Visio_TLB.IVApplication;
begin
  VisioAppIntf := VisioApp;
  ShowMessage(VisioAppIntf.ProductName);
end;

这篇关于接口编组在Delphi的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！