How to Write and Read a Color in C#

This article shows how to transform a color in hexadecimal representation.

Transforming a color in hexa representation using following function:

private string WriteHexString(byte aobjColR, byte aobjColG, byte aobjColB)
{
string strRet;
byte[] btR = {aobjColR};
string strR = ToHexString(btR);
strRet = strR;
byte[] btG = {this.colorDialog1.Color.G};
string strG = ToHexString(btG);
strRet += strG;
byte[] btB = {this.colorDialog1.Color.B};
string strB = ToHexString(btB);
strRet += strB;
return strRet;
}
//WriteHexString

This function transform a Color (defined as Color.R, Color.G, Color.B) in hexa representation (as string) and use following helper functions:

private static string ToHexString(byte[] bytes)
{
char[] chars = new char[bytes.Length * 2];
for (int i = 0; i < bytes.Length; i++)
{
int b = bytes[i];
chars[i * 2] = hexDigits[b >> 4];
chars[i * 2 + 1] = hexDigits[b & 0xF];
}
return new string(chars);
}
//ToHexString
 
static char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7','8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

To transform "hexa" representation back in color we can use following function:

private Color GetColor(string astrHexString)
{
string strR;
string strG;
string strB;
string strRL;
string strRR;
string strGL;
string strGR;
string strBL;
string strBR;
int iR;
int iG;
int iB;
int iRL;
int iRR;
int iGL;
int iGR;
int iBL;
int iBR;
Color c;
strR = astrHexString.Substring(0,2);
strG = astrHexString.Substring(2,2);
strB = astrHexString.Substring(4,2);
strRL = strR.Substring(0,1);
strRR = strR.Substring(1,1);
strGL = strG.Substring(0,1);
strGR = strG.Substring(1,1);
strBL = strB.Substring(0,1);
strBR = strB.Substring(1,1);
iRL = GetIntFromHex(strRL);
iRR = GetIntFromHex(strRR);
iGL = GetIntFromHex(strGL);
iGR = GetIntFromHex(strGR);
iBL = GetIntFromHex(strBL);
iBR = GetIntFromHex(strBR);
iR = 16 * iRL + iRR;
iG = 16 * iGL + iGR;
iB = 16 * iBL + iBR;
c = Color.FromArgb(iR, iG, iB);
return c;
}
//GetColour

and helper function:

private int GetIntFromHex(string strHex)
{
switch (strHex)
{
case("A"):
{
return 10;
}
case("B"):
{
return 11;
}
case("C"):
{
return 12;
}
case("D"):
{
return 13;
}
case("E"):
{
return 14;
}
case("F"):
{
return 15;
}
default:
{
return int.Parse(strHex);
}
}
}
//GetIntFromHex 

The complete code is in zip file.