C# - 如何将对象转换为 IntPtr 并返回? [英] C# - How To Convert Object To IntPtr And Back?

问题描述

我想将对象从托管代码传递到 WinApi 函数作为 IntPtr.它会将此对象作为 IntPtr 传递回托管代码中的回调函数.它不是结构，而是类的实例.

I want to pass an object from managed code to a WinApi function as IntPtr. It will pass this object back to my callback function in managed code as IntPtr. It's not a structure, it's an instance of a class.

如何将 object 转换为 IntPtr 并返回?

How do I convert object to IntPtr and back ?

推荐答案

所以如果我想通过 WinApi 将列表传递给我的回调函数，我使用 GCHandle

So if I want to pass a list to my callback function through WinApi I use GCHandle

// object to IntPtr (before calling WinApi):
List<string> list1 = new List<string>();
GCHandle handle1 = GCHandle.Alloc(list1);
IntPtr parameter = (IntPtr) handle1;
// call WinAPi and pass the parameter here
// then free the handle when not needed:
handle1.Free();

// back to object (in callback function):
GCHandle handle2 = (GCHandle) parameter;
List<string> list2 = (handle2.Target as List<string>);
list2.Add("hello world");

感谢大卫·赫弗南

如评论中所述，您需要在使用后释放手柄.我也使用了铸造.使用静态方法 GCHandle.ToIntPtr(handle1) 和 GCHandle.FromIntPtr(parameter) 像 这里.我还没有验证过.

As noted in the comments, you need to free the handle after use. Also I used casting. It might be wise to use the static methods GCHandle.ToIntPtr(handle1) and GCHandle.FromIntPtr(parameter) like here. I haven't verified that.

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