c# - 无法编码结构的字段

Question

我在 dll 中有一个结构，类型如下。但是当我调试它时，出现以下异常。请帮助解决这个问题。

Cannot marshal field 'id' of type 'RCMMMResult_S': The type definition of this field has layout information but has an invalid managed/unmanaged type combination or is unmarshalable.

[StructLayout(LayoutKind.Sequential)]
public struct RCMMMResult_S
{

    public RCMMMResultID_s id;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
    public byte[] value;
   // [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
    public byte status;

    public RCMMMResult_S(bool init = true)
    {

        id = new RCMMMResultID_s();
        value = new byte[4];
        status = 0;
    }
} ;
[StructLayout(LayoutKind.Sequential, Pack = 1)]
[Serializable]
public struct RCMMMResultID_s
{

    [MarshalAs(UnmanagedType.I1, SizeConst = 1)]
    public byte analyte_id;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
    public byte unit_code;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
    public byte[] variant;
    public RCMMMResultID_s(bool init = true)
    {
        analyte_id = 0;
        unit_code = 0;
        variant = new byte[2];
    }
} ;

Answer 1

问题出在这里:

[MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
public byte unit_code;

这是一个单字节，不能用作 by-val 数组。 I1 可以正常工作。