结构指针和固定字符

Question

我的 C++ 中有这样的结构

struct ST_HDTextInfo
{
    char* font_name;                    
    char* text;                          
    unsigned int font_color;             
    unsigned int background_color;      
    int style;                          
    int font_size;                       
    struct ST_HDTextInfo* next;        
};

我在我的 C# 代码中像这样重新声明它

[StructLayout(LayoutKind.Sequential,Pack=4)]
    unsafe struct  ST_HDTextInfo
    {
        [MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 25)]
        public fixed char font_name[25];
        [MarshalAs(UnmanagedType.ByValTStr, ArraySubType = UnmanagedType.I1, SizeConst = 20)]
        public char[] text;
        [MarshalAs(UnmanagedType.SysUInt)]
        public uint font_color;
        [MarshalAs(UnmanagedType.SysUInt)]
        public uint background_color;
        [MarshalAs(UnmanagedType.SysInt)]
        public EN_FontStyle style;
        [MarshalAs(UnmanagedType.SysInt)]
        public int font_size;
        [MarshalAs(UnmanagedType.SysInt)]
        public ST_HDTextInfo* next;
    };

字段 next 是指向同一结构的指针。当我使用 char[] var 作为字符串变量时，因为结构没有固定大小 VS 在 public ST_HDTextInfo* [=21 上出错=]下一个 但是当使用 fixed char var[SIZE_OF_VAR] 时问题解决了但是又出现了另一个错误。填充 char* 变量是一个新问题！我使用此代码将计数字符串转换为 char*

IntPtr p = Marshal.StringToHGlobalAuto("Poor Richard");
char* newCharStr = (char*)(p.ToPointer());

text_info.font_name = newCharStr;

本站我的字符串转成char*但是VS报错"The left-hand side of an assignment must be a variable, property or indexer "!!!

Answer 1

我解决了这个问题。我使用这个示例代码

[StructLayoutAttribute(LayoutKind.Explicit, CharSet = CharSet.Auto, Size=80)]
    internal unsafe struct ST_HDTextInfo
    {
        [FieldOffset(0)]
        public fixed char text[25];
        [FieldOffset(0)]
        public fixed char font_name[20];
        [MarshalAs(UnmanagedType.I4)]
        [FieldOffset(0)]
        public uint font_color;
        [MarshalAs(UnmanagedType.I4)]
        [FieldOffset(0)]
        public uint background_color;
        [MarshalAs(UnmanagedType.I4)]
        [FieldOffset(0)]
        public EN_FontStyle style;
        [MarshalAs(UnmanagedType.I4)]
        [FieldOffset(0)]
        public int font_size;
        [FieldOffset(80 - sizeof(long))]
        public ST_HDTextInfo* next;
    };

结构指针和固定字符

struct pointer and fixed char

c#

c++

dll

struct

unmarshalling