編組C＃結構

Question

我正在嘗試序列化以下c＃結構：

[Serializable]
[StructLayout(LayoutKind.Sequential, Size = 70, CharSet = CharSet.Ansi)]
public struct USSDContinueModel
{
    [MarshalAs(UnmanagedType.U4)]
    public uint Command_Length;

    [MarshalAs(UnmanagedType.U4)]
    public uint Command_ID;

    [MarshalAs(UnmanagedType.U4)]
    public uint Command_Status;

    [MarshalAs(UnmanagedType.U4)]
    public uint Sender_ID;

    [MarshalAs(UnmanagedType.U4)]
    public uint Receiver_ID;

    [MarshalAs(UnmanagedType.U1)]
    public uint Ussd_Version;

    [MarshalAs(UnmanagedType.U1)]
    public uint Ussd_Op_Type;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 21)]
    public string MsIsdn;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 21)]
    public string Service_Code;

    [MarshalAs(UnmanagedType.U1)]
    public uint Code_Scheme;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 182)]
    public string Ussd_Content;

    // Calling this method will return a byte array with the contents
    // of the struct ready to be sent via the tcp socket.
    public byte[] Serialize()
    {
        // allocate a byte array for the struct data
        var buffer = new byte[Marshal.SizeOf(typeof(USSDContinueModel))];

        // Allocate a GCHandle and get the array pointer
        var gch = GCHandle.Alloc(buffer, GCHandleType.Pinned);
        var pBuffer = gch.AddrOfPinnedObject();

        // copy data from struct to array and unpin the gc pointer
        Marshal.StructureToPtr(this, pBuffer, false);
        gch.Free();

        return buffer;
    }

    // this method will deserialize a byte array into the struct.
    public void Deserialize(ref byte[] data)
    {
        var gch = GCHandle.Alloc(data, GCHandleType.Pinned);
        this = (USSDContinueModel)Marshal.PtrToStructure(gch.AddrOfPinnedObject(), typeof(USSDContinueModel));
        gch.Free();
    }
}

當我嘗試序列化該結構的實例時，請說：

        public USSDContinueModel continueModel;
        continueModel.Command_Length = 174;
        continueModel.Command_ID = 0x00000070;
        continueModel.Command_Status = 0;
        continueModel.Sender_ID = 0x01000005;
        continueModel.Receiver_ID = 0x2900AB12;
        continueModel.Ussd_Version = 0x20;
        continueModel.Ussd_Op_Type = 0x01;
        continueModel.MsIsdn = "08098765476";
        continueModel.Service_Code = "*308";
        continueModel.Code_Scheme = 0x44;
        continueModel.Ussd_Content = "1. Continue if you are 18+ 2. Exit i";

我不斷收到錯誤“類型：USSDcontinueModel無法編組為非托管結構；無法計算出有意義的大小或偏移量”。

我注意到當我將Ussd_Version，Ussd_Op_Type和Code_Scheme設置為[MarshalAs（UnmanagedType.U1）]時會發生這種情況，但是它與[MarshalAs（UnmanagedType.U4）]可以很好地工作。

[MarshalAs（UnmanagedType.U1）]是否不可編組？ 我該怎么辦？

Answer 1

問題在於定義：

[MarshalAs(UnmanagedType.U1)]
public uint Ussd_Op_Type;

關於成員的大小不確定。 如果互操作元帥使用成員的大小，它將計算4個字節，而如果使用MarshalAs屬性，它將計算1個字節。 更改成員以使用正確的尺寸類型，

[MarshalAs(UnmanagedType.U1)]
public byte Ussd_Op_Type;

應該解決這個問題。

Answer 2

因此，在采納@theB的建議之后，將U1數據類型聲明為字節。 問題已解決。 更新后的結構定義如下：

[Serializable]
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack=1)]
public struct USSDContinueModel
{
    [MarshalAs(UnmanagedType.U4)]
    public uint Command_Length;

    [MarshalAs(UnmanagedType.U4)]
    public uint Command_ID;

    [MarshalAs(UnmanagedType.U4)]
    public uint Command_Status;

    [MarshalAs(UnmanagedType.U4)]
    public uint Sender_ID;

    [MarshalAs(UnmanagedType.U4)]
    public uint Receiver_ID;

    [MarshalAs(UnmanagedType.U1)]
    public byte Ussd_Version;

    [MarshalAs(UnmanagedType.U1)]
    public byte Ussd_Op_Type;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 21)]
    public string MsIsdn;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 21)]
    public string Service_Code;

    [MarshalAs(UnmanagedType.U1)]
    public byte Code_Scheme;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 182)]
    public string Ussd_Content;

    // Calling this method will return a byte array with the contents
    // of the struct ready to be sent via the tcp socket.
    public byte[] Serialize()
    {
        // allocate a byte array for the struct data
        var buffer = new byte[Marshal.SizeOf(typeof(USSDContinueModel))];

        // Allocate a GCHandle and get the array pointer
        var gch = GCHandle.Alloc(buffer, GCHandleType.Pinned);
        var pBuffer = gch.AddrOfPinnedObject();

        // copy data from struct to array and unpin the gc pointer
        Marshal.StructureToPtr(this, pBuffer, false);
        gch.Free();

        return buffer;
    }

    // this method will deserialize a byte array into the struct.
    public void Deserialize(ref byte[] data)
    {
        var gch = GCHandle.Alloc(data, GCHandleType.Pinned);
        this = (USSDContinueModel)Marshal.PtrToStructure(gch.AddrOfPinnedObject(), typeof(USSDContinueModel));
        gch.Free();
    }
}