Alternative to BitConverter.ToInt32

I'm using BitConverter.ToInt32 to pack 3 byte values into an int, like so:

byte R = 0;
byte G = 0;
byte B = 0;
int i = BitConverter.ToInt32(new byte[] { R, G, B, 0 }, 0);

Is there a faster way to do this that doesn't involve the creation of a new int each time? Getting the bytes out of an int is easy:

int i = 34234;
byte B 开发者_运维问答= (byte)(i >> 0);
byte G = (byte)(i >> 8);
byte R = (byte)(i >> 16);

Is there a simple way to reverse this process and use bit-shifting to write the RGB bytes back over an existing int?

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int i = (B << 0) | (G << 8) | (R << 16);

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You ought to consider the Color structure. It has R, G and B properties and FromArgb() and ToArgb() methods.