c#调用delphi动态库？

Question

delphi定义了一个结构体

THF_MeterPackData = record
    h_OPFlag: Integer; 
    h_FactPayAmount: double; 
    h_AmmeterID: Int64;
    h_AreaID: Integer; 
    h_SysCode: Integer; 
    h_MeterType: Integer;
    h_HgBaute: Integer;
    h_MaxAllowLoad: Integer;
    h_AmmeterConstant : Integer;
    h_CutAmount: double;
    h_baojing: double; 

    h_WaterNo : integer;

    h_AmmeterStatus: Integer;
    h_RemainAmount: double;

    h_MeterMode: Integer;
    h_Price:double;
    h_StepPrice: array[0..3] of double;
    h_StepAmount: array[0..3] of double;
    h_PriceDateTime:TDateTime;
    h_ParaVer:Integer;
    h_TJAmount:double;
    h_PlugDate: TDateTime;
    h_CardVer:Integer;
    h_IsInsert : Integer;
    h_meterCode:Int64; 
    h_MonthAmount: array[0..11] of Double; 
End;

一个指针
Phf_MeterPackData = ^THF_MeterPackData;
一个方法
function Read_Card_Public(m_Data: Phf_MeterPackData) : Integer; stdcall; external 'xxx.dll';
c# 调用这个动态库的Read_Card_Public方法时，使用的也是结构体指定IntPtr，为什么到h_AmmeterID值时还正常，后面全都没有值了？用delphi自身调用就没问题？
THF_MeterPackData data = InitInfo();
int len = Marshal.SizeOf(data);//计算对象大小
IntPtr ptr = Marshal.AllocHGlobal(len);//从非托管内存中分配内存
Marshal.StructureToPtr(data, ptr, true);//将数据从托管对象封送到非托管内存块
ret = API.HFmeterAPI.Read_Card_Public(ref ptr);
c# 中定义的结构体

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
public struct THF_MeterPackData
{
    public int h_OPFlag;
    public Double h_FactPayAmount;
    public Int64 h_AmmeterID;
    public int h_AreaID;
    public int h_SysCode;
    public int h_MeterType;
    public int h_HgBaute;
    public int h_MaxAllowLoad;
    public int h_AmmeterConstant;
    public Double h_CutAmount;
    public Double h_baojing;
    public int h_WaterNo;
    public int h_AmmeterStatus;
    public Double h_RemainAmount;
    public int h_MeterMode;
    public Double h_Price;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4, ArraySubType = UnmanagedType.Struct)]
    public Double[] h_StepPrice;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4, ArraySubType = UnmanagedType.Struct)]
    public Double[] h_StepAmount;
    public DateTime h_PriceDateTime;
    public int h_ParaVer;
    public Double h_TJAmount;
    public DateTime h_PlugDate;
    public int h_CardVer;
    public int h_IsInsert;
    public Int64 h_meterCode;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 12, ArraySubType = UnmanagedType.Struct)]
    public Double[] h_MonthAmount;
}