Convert Long (6/8 hex colour) to a Color struct.

ColourConvert.cs

///<Summary>
/// Converts a hexadecimal colour code (8-hex with alpha) into a .net Color struct.
///</Summary>
///<remarks>
/// If the input string is invalid, will throw an exception from parsing, you 
/// should handle this in the callee.
///</remarks>
///<param name="colour">The colour in numerical form. Prefix with # for hexadecimal format.</param>
///<example>
/// Example of converting hexadecimal string and ulong values to a Color.
/// <code> 
///  var color1 = ConvertToColour("#FFAABBCC");
///  var color2 = ConvertToColour("4289379276");
/// </code>
///</example>
public Color ConvertToColour(string colour) 
{
	ulong longColour;

	if (colour.StartsWith("#"))
	{
		longColour = UInt64.Parse(colour.TrimStart('#'), NumberStyles.HexNumber);
	}
	else
	{
		longColour = UInt64.Parse(colour, NumberStyles.Integer);
	}


	var bytes = GetBytes(longColour);

	return Color.FromArgb(bytes[0], bytes[1], bytes[2], bytes[3]);
}

/// <summary>
/// Return an array of bytes from the passed ulong
/// </summary>
private byte[] GetBytes(ulong value)
{
	Byte[] byteArray = new byte[4];

	// convert from an unsigned long int to a 4-byte array
	byteArray[0] = (byte)((int) ((value >> 24) & 0xFF));
	byteArray[1] = (byte)((int) ((value >> 16) & 0xFF));
	byteArray[2] = (byte)((int) ((value >> 8) & 0XFF));
	byteArray[3] = (byte)((int) ((value & 0XFF)));
	return byteArray;
}