用多个指针在C#中封送本机.dll

使用C++编写以下代码：

• NCOID是连接标识符
• pParName参数名
• pSubName子参数名称（如果有）
• pValue\u out指向长度为FCL\u PAR\u VALUE\u LENGH的字符数组的指针
• nValue size pValue_out向量的实际大小（至少FCL_PAR_VALUE_LENGH）

我的尝试是：

[DllImport("mydll.dll", CharSet = CharSet.Ansi,CallingConvention=CallingConvention.Cdecl)]
public static extern int ReadParameter(ConnectionId_T pConId, IntPtr pParName,
    ref IntPtr pSubName, ref IntPtr[] pValue_out, int nValueSize);

我使用以下代码调用该函数：

# nConId is returned from another function and the his value is 0

public const int FCL_PAR_VALUE_LENGH = 128; 

string param_string = "AUXF";
IntPtr pParName = (IntPtr)Marshal.StringToHGlobalAnsi(param_string);

string subparam_string = "T";
IntPtr pSubName = (IntPtr)Marshal.StringToHGlobalAnsi(subparam_string);

IntPtr[] aParValue = new IntPtr[FCL_PAR_VALUE_LENGH]; 

int returnedValue = ReadParameter(nConId, pParName, ref pSubName,
    ref aParValue, FCL_PAR_VALUE_LENGH);

当我运行代码时，我得到一个AccessViolationException，因此我猜我的调用中有问题

我的马歇尔错了吗？为了获得良好的响应，我需要在代码中做哪些更改

---

PS：我也知道这个调用也会返回一些东西到

aParValue

你对那些

char*

s太过努力了。将

System.String

封送用于输入，将

StringBuilder

封送用于输出是完全合法的（并受到鼓励）

[DllImport("mydll.dll", CharSet = CharSet.Ansi,CallingConvention=CallingConvention.Cdecl)]
public static extern int ReadParameter(
    ConnectionId_T pConId, 
    string pParName, 
    string pSubName,
    StringBuilder pValue_out,
    int nValueSize);

用法

您没有给出任何关于

连接id\u t

的基本类型的指示，因此我假设您已经排除了这一问题

---

工作起来很有魅力！非常感谢：）

[DllImport("mydll.dll", CharSet = CharSet.Ansi,CallingConvention=CallingConvention.Cdecl)]
public static extern int ReadParameter(
    ConnectionId_T pConId, 
    string pParName, 
    string pSubName,
    StringBuilder pValue_out,
    int nValueSize);

const int sbLength = 256; //use a domain relevant value
StringBuilder sb = new StringBuilder(sbLength + 1); //for null character, hard to say if you need it without seeing the C++ code, but easier to just add it than find out.
int result = ReadParameter(conId, "paramname", "paramsubname", sb, sbLength);