c# Struct Marshal for c++ dll

c++

typedef struct
{
HANDLE aaa;
HWND bbb;
BYTE ccc[2500];

} SStruct, LPSCStruct;


BOOL __stdcall func1(LPSCStruct zzz);



c#
public struct LPSCStruct
{
    public int aaa;
    public IntPtr bbb;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2500)]
    public byte[] ccc;
}


public partial class Form1 : Form /*, IMessageFilter*/
{      
    [DllImport("test.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Auto, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.I1)]
    unsafe extern public static bool func1(IntPtr zzz);
   
    public LPSCStruct sss;
    public LPSCStruct rrr;
    public IntPtr m_lpstruct;
   
    private void Form1_Load(object sender, EventArgs e)
    {
        sss = new LPSCStruct();
    }  
   
    private IntPtr MarshalToPointer(object data)
    {
        IntPtr buf = Marshal.AllocHGlobal(Marshal.SizeOf(pse));
        Marshal.StructureToPtr(data, buf, false);
        return buf;
    }

    private object MarshalToStruct(IntPtr buf, Type t)
    {
        return Marshal.PtrToStructure(buf, t);
    }  
   
    private void button1_Click(object sender, EventArgs e)
    {
        sss.bbb = FindWindow(null, "Form1");

        m_lpstruct = MarshalToPointer(sss);

        bool bRtn = func1(m_lpstruct);
        if (bRtn)
        {
            rrr = (LPSCStruct)MarshalToStruct(m_lpstruct, typeof(LPSCStruct));

            textBox1.AppendText(Encoding.Default.GetString(rrr.ccc));
        }          
    }