C# – Converting int[] to byte[]

arraysc++type-conversion

I know how to do this the long way: by creating a byte array of the necessary size and using a for-loop to cast every element from the int array.

I was wondering if there was a faster way, as it seems that the method above would break if the int was bigger than an sbyte.

Best Answer

If you want a bitwise copy, i.e. get 4 bytes out of one int, then use Buffer.BlockCopy:

byte[] result = new byte[intArray.Length * sizeof(int)];
Buffer.BlockCopy(intArray, 0, result, 0, result.Length);

Don't use Array.Copy, because it will try to convert and not just copy. See the remarks on the MSDN page for more info.

Related Solutions

C# – How to Convert Value Type to byte[]

To convert any value types (not just primitive types) to byte arrays and vice versa:

    public T FromByteArray<T>(byte[] rawValue)
    {
        GCHandle handle = GCHandle.Alloc(rawValue, GCHandleType.Pinned);
        T structure = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
        handle.Free();
        return structure;
    }

    public byte[] ToByteArray(object value, int maxLength)
    {
        int rawsize = Marshal.SizeOf(value);
        byte[] rawdata = new byte[rawsize];
        GCHandle handle =
            GCHandle.Alloc(rawdata,
            GCHandleType.Pinned);
        Marshal.StructureToPtr(value,
            handle.AddrOfPinnedObject(),
            false);
        handle.Free();
        if (maxLength < rawdata.Length) {
            byte[] temp = new byte[maxLength];
            Array.Copy(rawdata, temp, maxLength);
            return temp;
        } else {
            return rawdata;
        }
    }

C# – Convert Byte Array to Int

BitConverter is the correct approach.

Your problem is because you only provided 8 bits when you promised 32. Try instead a valid 32-bit number in the array, such as new byte[] { 0x32, 0, 0, 0 }.

If you want an arbitrary length array converted, you can implement this yourself:

ulong ConvertLittleEndian(byte[] array)
{
    int pos = 0;
    ulong result = 0;
    foreach (byte by in array) {
        result |= ((ulong)by) << pos;
        pos += 8;
    }
    return result;
}

It's not clear what the second part of your question (involving strings) is supposed to produce, but I guess you want hex digits? BitConverter can help with that too, as described in an earlier question.

Best Answer

Related Solutions

C# – How to Convert Value Type to byte[]

C# – Convert Byte Array to Int

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