CSharp如何调用dll中带指针参数.docx

1、CSharp如何调用dll中带指针参数CSharp如何调用dll中带指针参数C#调用C+DLL的方法，不同参数类型的调用方法1. 参数为基本类型，例如int, float, char等C+void fun(int value);void fun(float vaue);void fun(char ch);C#DllImport(xxx.dll)public static extern void fun(Int32 value);DllImport(xxx.dll)public static extern void fun(float value);DllImport(xxx.dll)publi

2、c static extern void fun(char ch);2. 参数为基本类型 + 指针， 例如int*, float*, char*等C+void fun(int* value);void fun(float* vaue);void fun(char* ch);C#DllImport(xxx.dll)public static extern void fun(ref Int32 value);DllImport(xxx.dll)public static extern void fun(ref float value);参数为char*，在C#中有几种实现方式A. public s

3、tatic extern void fun(string ch); /ch内容不会改变B. public static extern void fun(StringBuilder ch); /ch内容会改变3. 参数为结构体C+struct point int value; /基本类型 char ch; /基本类型 int number100; /数组 char buffer100; /字符串数组 ;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct point public Int32 value; pu

4、blic char ch; MarshalAs(UnmanagedType.ByValArray, SizeConst = 100) public Int32 number; MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100) public char buffer;DllImport(xxx.dll)public static extern void fun(point pt);4. 参数为结构体指针C+void fun(point* pt);C#DllImport(xxx.dll)public static extern void fun(

5、ref point pt);5. 参数为结构体， 并且结构体还嵌套结构体C+struct point int value; /基本类型 char ch; /基本类型 int number100; /数组 char buffer100; /字符串数组 struct point pt; /嵌套结构体;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct point public Int32 value; public char ch; MarshalAs(UnmanagedType.ByValArray, Siz

6、eConst = 100) public Int32 number; MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100) public char buffer; public point pt;DllImport(xxx.dll)public static extern void fun(point pt);6. 参数为结构体， 并且结构体还嵌套结构体指针或者双指针C+struct point int value; /基本类型 char ch; /基本类型 int number100; /数组 char buffer100; /字符串数组 s

7、truct point* p1; /嵌套结构体指针 struct point* p2; /嵌套结构体双指针;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct point public Int32 value; public char ch; MarshalAs(UnmanagedType.ByValArray, SizeConst = 100) public Int32 number; MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100) public c

8、har buffer; public IntPtr p1; /使用IntPtr替代嵌套指针 public IntPtr p2; /使用IntPtr替代嵌套指针DllImport(xxx.dll)public static extern void fun(point pt);由于嵌套指针的使用比较复杂，需要借助一些手段才能够确保正常调用DLL方法C#class Program StructLayout(LayoutKind.Sequential) public struct point public Int32 value; public char ch; MarshalAs(Unmanaged

9、Type.ByValArray, SizeConst = 100) public Int32 number; MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100) public char buffer; public IntPtr p1; /使用IntPtr替代嵌套指针 public IntPtr p2; /使用IntPtr替代嵌套指针 DllImport(xxx.dll) public static extern void fun(point pt); static void Main(string args) point pt = new

10、point(); pt.p1 = Marshal.AllocHGlobal(Marshal.Sizeof(typeof(point); pt.p2 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point) * 2); try pt.value = 1; /实现给p1赋值 point ptt = new point(); ptt.value = 1; Marshal.StructureToPtr(ptt, pt.p1, false); /实现给p2赋值 /由于双指针不能够直接传值，需要用到中间结构的数组指针 IntPtr ptr = new IntP

11、tr2; ptr0 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point); ptr1 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point); try Marshal.StructureToPtr(ptt, ptr0, false); Marshal.Copy(ptr, 0, pt.p2, 2); fun(pt); /测试返回的指针值是否正确 ptt = (point)Marshal.PtrToStructure(pt.p1, typeof(point); Marshal.Copy(pt.p2,

12、ptr, 0, 2); ptt = (point)Marshal.PtrToStructure(ptr0, typeof(point); ptt = (point)Marshal.PtrToStructure(ptr1, typeof(point); catch(System.Exception e) string str = e.Message; finally Marshal.FreeHGlobal(ptr0); Marshal.FreeHGlobal(ptr1)； catch(System.Exception e) string str = e.Message; finally Marshal.FreeHGlobal(pt.p1); Marshal.FreeHGlobal(pt.p2)；