将结构数组编组到C＃中的指针(Marshalling an array of structs to a pointer in C#)
我试图调用一个看起来像这样的非托管函数（DATA是我的C＃结构体）：
[DllImport("data.dll")] internal static unsafe extern int MyExternalFunction(DATA* pData, uint numElements);这是我从C＃调用函数的方式：
DATA[] data = new DATA[64]; fixed (DATA* pData = data ) { MyExternalFunction(pData, 64); } [StructLayout(LayoutKind.Sequential)] internal struct DATA { internal uint a; internal uint b; internal uint c; internal POINT pos; } [StructLayout(LayoutKind.Sequential)] internal struct POINT { internal int x; internal int y; }不幸的是我得到这个错误：“不能编组'参数＃1'：指针不能引用编组结构。”
如果它有什么区别，我的数据结构在它里面嵌套了结构。 我无法控制这种外部方法的设计。 调用这个函数并接收一个结构数组的正确方法是什么？
I am trying to call an unmanaged function that looks like this (DATA is my C# struct):
[DllImport("data.dll")] internal static unsafe extern int MyExternalFunction(DATA* pData, uint numElements);This is how I'm calling the function from C#:
DATA[] data = new DATA[64]; fixed (DATA* pData = data ) { MyExternalFunction(pData, 64); } [StructLayout(LayoutKind.Sequential)] internal struct DATA { internal uint a; internal uint b; internal uint c; internal POINT pos; } [StructLayout(LayoutKind.Sequential)] internal struct POINT { internal int x; internal int y; }Unfortunately I get this error: "Cannot marshal 'parameter #1': Pointers cannot reference marshaled structures."
If it makes any difference, my DATA struct has nested structs inside it. I have no control over how this external method is designed. What is the correct way to call this function and receive an array of structs?
原文：https://stackoverflow.com/questions/7363821
更新时间：2023-09-27 09:09
最满意答案
试试这个：
- (void)saveImage: (UIImage*)image { if (image != nil) { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString* path = [documentsDirectory stringByAppendingPathComponent: @"test.png" ]; NSData* data = UIImagePNGRepresentation(image); [data writeToFile:path atomically:YES]; } } - (UIImage*)loadImage { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString* path = [documentsDirectory stringByAppendingPathComponent: @"test.png" ]; UIImage* image = [UIImage imageWithContentsOfFile:path]; [self sendAction:path]; return image; }Try this one:
- (void)saveImage: (UIImage*)image { if (image != nil) { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString* path = [documentsDirectory stringByAppendingPathComponent: @"test.png" ]; NSData* data = UIImagePNGRepresentation(image); [data writeToFile:path atomically:YES]; } } - (UIImage*)loadImage { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString* path = [documentsDirectory stringByAppendingPathComponent: @"test.png" ]; UIImage* image = [UIImage imageWithContentsOfFile:path]; [self sendAction:path]; return image; }
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