[英]Entity Framework C# - Moving data from one database to another with similar structure
[英]Moving structure data in C#
可以说我在C中有以下结构
typedef struct
{
int field1;
char field2[16];
} MYSTRUCT;
现在我有一个C程序,用一个指向MYSTRUCT的指针调用,我需要填充结构,例如,
int MyCall(MYSTRUCT *ms)
{
char *hello = "hello world";
int hlen = strlen(hello);
ms->field1 = hlen;
strcpy_s(ms->field2,16,hello);
return(hlen);
}
我如何用C#编写MyCall? 我在Visual Studio 2010中尝试过这个:
...
using System.Runtime.InteropServices;
[StructLayout(LayoutKind.Explicit)]
public struct MYSTRUCT
{
[FieldOffset(0)]
UInt32 field1;
[FieldOffset(4)]
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
string field2;
}
public int MyProc(ref MYSTRUCT ms)
{
string hello = "hello world";
int hlen = hello.Length;
Marshal.Copy(hello, ms.field2, 0, hlen); // doesn't work
Array.Copy(hello, ms.field2, hlen); // doesn't work
// tried a number of other ways with no luck
// ms.field2 is not a resolved reference
return(hlen);
}
感谢您提供正确方法的任何提示。
尝试更改StructLayout。
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
public struct MYSTRUCT
{
public UInt32 field1;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
public string field2;
}
既然,您作为参考传递,您是否尝试将其设置为:
public int MyProc(ref MYSTRUCT ms)
{
string hello = "hello world";
ms.field2 = hello;
return hello.Length;
}
使用ref
关键字时,您将调用MyProc
如下所示:
static void Main(string[] args)
{
var s = new MYSTRUCT();
Console.WriteLine(MyProc(ref s)); // you must use "ref" when passing an argument
Console.WriteLine(s.field2);
Console.ReadKey();
}
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