将struct handle从managed转换为非托管C ++ / CLI [英] convert struct handle from managed into unmanaged C++/CLI
问题描述
在C#中,我定义了一个结构:
In C#, I defined a struct:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct MyObject
{
[MarshalAs(UnmanagedType.LPWStr)]
public string var1;
[MarshalAs(UnmanagedType.LPWStr)]
public string var2;
};
我在C ++中有这个结构:
I have this struct in C++:
public value struct MyObject
{
LPWSTR var1;
LPWSTR var2;
};
在C ++的方法中,这是一个从C#调用的公共类:
And in the method of C++ which is a public class to be called from C#:
TestingObject(MyObject^ configObject)
{
// convert configObject from managed to unmanaged.
}
对象被正确调试,可以看到两个字符串var1和var2。然而,现在的问题是,我需要编组对象: configObject
到一个非托管对象。
The object is debugged correctly that I can see two strings var1 and var2. However, the problem now is that I need to marshal the object: configObject
into an unmanaged object.
想到的是这样做:
TestingObject(MyObject^ configObject)
{
// convert configObject from managed to unmanaged.
MyObject unmanagedObj = (MyObject)Marshal::PtrToStructure(configObject, MyObject);
}
这是我能想到的,但是当然,
That is what I can think of but off course, I got this error:
错误2错误C2275:'MyObject':非法将此类型用作
表达式
Error 2 error C2275: 'MyObject' : illegal use of this type as an expression
将托管对象转换为非托管对象是正确的吗?如果是,我如何能够正确地 Marshal :: PtrToStructure
?
Is that right to convert the managed object into unmanaged object? if yes, how can I can that Marshal::PtrToStructure
correctly?
如果没有,你能提供给我正确的方式?
IF no, could you please provide me a correct way?
提前感谢。
推荐答案
Marshal :: PtrToStructure
它将非托管指针转换为托管对象。您希望 Marshal :: StructureToPtr
。
Marshal::PtrToStructure
does the opposite of what you want, it converts an unmanaged pointer to a managed object. You want Marshal::StructureToPtr
.
此外,您需要定义一个非托管类,因为MyObject是一个托管类型。假设你这样做了,你可以这样做(只是从C#示例转换而来):
Also, you would need to define an unmanaged class, because MyObject is a Managed Type. Assuming you have done that, you could do it like this (just converted this from the C# sample):
IntPtr pnt = Marshal::AllocHGlobal(Marshal::SizeOf(configObject));
Marshal.StructureToPtr(configObject, pnt, false);
然后你有一个指向数据的指针,你可以 memcpy
或任何到您的原生结构中。
You then have a pointer to the data, which you can memcpy
or whatever into your native struct.
但并将保持托管类型。如果你想要一个真正的非托管类型,你必须定义一个匹配托管结构。
But MyObject
is and will stay a managed type. If you want a truly unmanaged type, you have to define one that matches the managed struct.
只是想知道,为什么在托管结构中使用非托管LPWSTR?
Just wondering, why are you using unmanaged LPWSTR in a managed struct?
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