如何编组C＃结构数组？

Question

I'm developing a fingerprint login for a HRM system. Sample code given with the SDK allows verifying with one template. Here is the segment of the code.

 
    BSTypes.ABS_BIR ppEnrolledTemplate; //Load the template array to ppEnrolledTemplate

    IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(ppEnrolledTemplateArray[i]));

    Marshal.StructureToPtr(ppEnrolledTemplateArray[i], ptr, false);

    res = BSApi.ABSVerify(conn, ref op, 1, ref ptr, ref matching_slot, 0);

According to the SDK documentation( Link ) ABSVerify method allows to input template array as one of the parameters. I'm finding difficulties marshaling ABS_BIR struct array. Here is the struct for ABS_BIR.

[StructLayout(LayoutKind.Sequential)]      
        public struct ABS_BIR
        {
            public ABS_BIR_HEADER Header;   // BIR header
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2560)]
            public byte[] Data;     // The data composing the fingerprint template.
        }

This is the solution I came with. I wrote a method called ReadyTemplate()

private void readTemplate() {
        //read template from binary file
        for (int i = 0; i < 4; i++)
        {
            FileStream objFileStream;
            BinaryReader objBinaryReader;
            try
            {
                // ========== Updated by bubz ============
                byte[] data;
                objFileStream = new FileStream(i + ".bin", FileMode.Open);
                objBinaryReader = new BinaryReader(objFileStream);
                data = objBinaryReader.ReadBytes((int)objFileStream.Length);

                GCHandle pinnedData = GCHandle.Alloc(data, GCHandleType.Pinned);
                ppEnrolledTemplateArray[i] = (BSTypes.ABS_BIR)Marshal.PtrToStructure(pinnedData.AddrOfPinnedObject(), typeof(BSTypes.ABS_BIR));

                displayOut(0, 0, "Template retrieved from PC.");
                displayOut(0, 0, i.ToString());
                objBinaryReader.Close();

                // ============ end ====================


            }

            catch (FileNotFoundException FileEx)
            {
                displayOut(2, 0, FileEx.Message);
                return;
            }

            catch (Exception Ex)
            {
                displayOut(2, 0, Ex.Message);
                return;
            }
        }

    }

Please help me.Thanks.

Answer 1

Check me if I'm wrong, but I believe I read somewhere that marshaling a struct to an array can be performed by doing the following:

[StructLayout(LayoutKind.Sequential)]
[MarshalAs(UnmanagedType.ByValArray)]      
public struct ABS_BIR
{
    public ABS_BIR_HEADER Header;   // BIR header

    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2560)]
    public byte[] Data;     // The data composing the fingerprint template.
}

And then simply passing the struct in the place of the array.

Good luck