Dllimport char* [] 從 C 到 C#

Question

如何使用 C# 的 Dllimport 從 C 庫中獲取字符串數組

int GetClasses (int *NumberofClasses, char *ClassNames[], int arrayLength)

我已經嘗試 StringBuilder[] 和許多 MarshalAsAttributes 來接收 ClassNames 但仍然無法正常工作並導致 memory 違規

我對這個 C 方法的解釋如下。

int GetClasses(int * NumberofClasses, char * ClassNames[], int arrayLength)

This function will get the total number of unique classes and each unique class name.

Parameters:
NumberofClasses: Total number of unique classes.
ClassNames: Array of allocated char * to return class names.
arrayLength: Length of passed ClassNames array. If the result exceeds this array length, this function will fail with an error code.

Returns: Zero for success. Non-zero for error

我的聲明是

[DllImport(@".\library.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
private static extern Int16 GetClasses(ref UInt16 NumberofClasses, StringBuilder[]  ClassNames, UInt16 arrayLength);

我有通過

類數=16，

ClassNames= StringBuilder[16] 每個容量為 256

數組長度=16

接到這個電話

Answer 1

最后我通過修改參數類型的聲明得到了成功調用。

[DllImport(@".\library.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
    private static extern Int16 GetClasses(ref UInt16 NumberofClasses, [In][Out][MarshalAs(UnmanagedType.LPArray)] string[] ClassNames, UInt16 arrayLength);

並為參數 ClassNames 分配一個字符串數組

string[] names = new string[NumberOfClasses];

for (int i = 0; i < names.Length; i++)
{
    names[i] = new string(new char[256]);
}