无法从返回值指向接口的指针调用方法 [英] Cannot call method from return value's pointer to interface

问题描述

   

当我尝试访问界面的功能时，我从方法调用中收到错误。

 
 My_DLL :: IStubRequest * request = NULL; 
 CoCreateInstance（__ uuidof（My_DLL :: StubRequest），NULL，CLSCTX_INPROC_SERVER，__ uuidof（My_DLL :: IStubRequest），（void **）& request）; //还行吧。 
 My_DLL :: IStubResponse * response = NULL; 
 request-> DoSomething（（My_DLL :: _ St​​ubResponse **）& response）; // HRESULT没问题，但在没有返回值的方法上使用它会导致System.AccessViolationException 
 
 response-> Print（）; //  System.AccessViolationException  
 BSTR * valuePtr = NULL; 
 response-> GetValue（valuePtr）; //这不行
 

C＃中的Stub *类如下：

 
命名空间com.myApp.msg 
 {
 
公共接口IStubRequest 
 {
 StubResponse DoSomething（）; 
} 
 
公共类StubRequest：IStubRequest 
 {
 public StubRequest（）
 {
} 
 public StubResponse DoSomething（） 
 {
 //做某事并返回StubResponse 
} 
} 
 
公共接口IStubResponse 
 {
 string GetValue（） ; 
 
   void Print（）; 
} 
 
公共类StubResponse：IStubResponse 
 {
 private string value = null; 
 public StubResponse（string value）
 {
 this.value = value; 
} 
公共字符串GetValue（）
 {
返回值; 
} 
 
   public void Print（）{
 
   Console.WriteLine（" hello world"）; 
 
  } 
} 
} 
 

GetValue（）调用会产生一个弹出窗口，说明是


>运行时检查失败＃0 - ESP的值未在函数调用中正确保存。这通常是调用使用一个调用约定声明的函数的结果，该函数使用不同的调用约定声明的函数。



如何修复它？

$


$

解决方案

您好，

My_DLL :: IStubRequest是用户定义的类型。它是什么类型的？

并在用户定义的类型My_DLL :: IStubRequest中向我们展示GetValue的声明（s？）。

问候，吉

   

I am getting error from a method call when I try to access the functions of an interface.

My_DLL::IStubRequest *request = NULL;
CoCreateInstance(__uuidof(My_DLL::StubRequest), NULL, CLSCTX_INPROC_SERVER, __uuidof(My_DLL::IStubRequest), (void**)&request); //this is ok.
My_DLL::IStubResponse *response = NULL;
request->DoSomething((My_DLL::_StubResponse**) &response); //HRESULT is ok, but using it on a method without return value will cause System.AccessViolationException
response->Print();//System.AccessViolationException
BSTR * valuePtr = NULL;
response->GetValue(valuePtr); //this is not ok

The Stub* classes in C# are as follows:

namespace com.myApp.msg
{
	
	public interface IStubRequest
	{
		StubResponse DoSomething();
	}

	public class StubRequest : IStubRequest
	{
		public StubRequest()
		{
		}
		public StubResponse DoSomething()
		{
			//do something and return StubResponse
		}
	}

	public interface IStubResponse
	{
		string GetValue();
		void Print();
	}

	public class StubResponse : IStubResponse
	{
		private string value = null;
		public StubResponse(string value)
		{
			this.value = value;
		}
		public string GetValue()
		{
			return value;
		}
		public void Print(){
			Console.WriteLine("hello world");
		}
	}
}

The GetValue() call results in a popup window saying

>Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call. This is usually a result of calling a function declared with one calling convention with a function declared with a different calling convention.

How to fix it?

解决方案

Hello,

My_DLL::IStubRequest is a user defined type. What type is it?

And show us the declaration(s?) of GetValue in your user defined type My_DLL::IStubRequest.

Regards, Guido

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