Convert hexadecimal to octal and octal

Adapted from 8 to 16

/// <Summary>
/// Convert the hexadecimal number to the hexadecimal number
/// </Summary>
/// <Param name = "convertfrom"> hexadecimal number </param>
/// <Returns> eight records </returns>
Private string convertnumber8to16 (string convertfrom ){
Try
{
String check = convertfrom. replace ("0", String. empty ). replace ("1", String. empty ). replace ("2", String. empty ). replace ("3", String. empty ). replace ("4", String. empty ). replace ("5", String. empty ). replace ("6", String. empty ). replace ("7", String. empty ). replace ("8", String. empty ). replace ("9", String. empty ). replace ("A", String. empty ). replace ("B", String. empty ). replace ("C", String. empty ). replace ("D", String. empty ). replace ("e", String. empty ). replace ("F", String. empty );

If (check. length> 0)
{
// Errorhandle
Return string. empty;
}
String convertor = string. Empty, convertto2; // number of targets convertor: Convert octal from,

Convertto2 = convertnumber16to2 (convertfrom); // convert to binary first
Convertid = convertnumber2to8 (convertto2 );
/// Convert binary to decimal
// Int64 intten = convert. toint32 (convertto2.trim (), 2 );
/// Convert the decimal number to the octal number
// Convertize = convert. tostring (intten, 8 );
Return convertings;
}
Catch (exception ex) {return "";}
}

/// <Summary>
/// Convert hexadecimal to binary
/// </Summary>
/// <Param name = "convertfrom"> hexadecimal number </param>
/// <Returns> binary number </returns>
Private string convertnumber16to2 (string convertfrom)
{
String check = convertfrom. replace ("0", String. empty ). replace ("1", String. empty ). replace ("2", String. empty ). replace ("3", String. empty ). replace ("4", String. empty ). replace ("5", String. empty ). replace ("6", String. empty ). replace ("7", String. empty ). replace ("8", String. empty ). replace ("9", String. empty ). replace ("A", String. empty ). replace ("B", String. empty ). replace ("C", String. empty ). replace ("D", String. empty ). replace ("e", String. empty ). replace ("F", String. empty );
If (check. length> 0)
{
// Errorhandle
Return string. empty;
}
String convertor = string. Empty, bit;
For (INT I = convertfrom. Length-1; I> = 0; I --)
{
Bit = convertfrom. substring (I, 1 );
Switch (BIT)
{
Case "0 ":
Convertings = "0000" + convertings;
Break;
Case "1 ":
Convertings = "0001" + convertings;
Break;

Case "2 ":
Convertings = "0010" + convertings;
Break;
Case "3 ":
Convertings = "0011" + convertings;
Break;
Case "4 ":
Convertings = "0100" + convertings;
Break;
Case "5 ":
Convertings = "0101" + convertings;
Break;
Case "6 ":
Convertings = "0110" + convertings;
Break;
Case "7 ":
Convertings = "0111" + convertings;
Break;
Case "8 ":
Convertings = "1000" + convertings;
Break;
Case "9 ":
Convertings = "1001" + convertings;
Break;
Case "":
Convertings = "1010" + convertings;
Break;
Case "B ":
Convertings = "1011" + convertings;
Break;
Case "C ":
Convertings = "1100" + convertings;
Break;
Case "D ":
Convertings = "1101" + convertings;
Break;
Case "E ":
Convertings = "1110" + convertings;
Break;
Case "F ":
Convertings = "1111" + convertings;
Break;
}
}
Return convertings;
}

/// <Summary>
/// Convert binary to octal
/// </Summary>
/// <Param name = "convertfrom"> binary number </param>
/// <Returns> eight records </returns>
Private string convertnumber2to8 (string convertfrom)
{
String check = convertfrom. Replace ("0", String. Empty). Replace ("1", String. Empty );
If (check. length> 0)
{
// Errorhandle
Return string. empty;
}
String convertor = string. Empty, bit;
For (INT I = convertfrom. Length-3; I> = 0; I-= 3)
{
Bit = convertfrom. substring (I, 3); // subtract 3 each time
Switch (BIT)
{
Case "000 ":
Convertor = "0" + convertor;
Break;
Case "001 ":
Convertor = "1" + convertor;
Break;
Case "010 ":
Convertor = "2" + convertor;
Break;
Case "011 ":
Convertor = "3" + convertor;
Break;
Case "100 ":
Convertor = "4" + convertor;
Break;
Case "101 ":
Convertor = "5" + convertor;
Break;
Case "110 ":
Convertor = "6" + convertor;
Break;
Case "111 ":
Convertor = "7" + convertor;
Break;
}
}
Int residue, temp = 0;
Residue = convertfrom. Length % 3; // returns the remainder.
String S = "";
If (residue! = 0)
{
If (residue = 1)
{
S = convertfrom. substring (0, 1 );
Temp = 1;
}

If (residue = 2)
{
S = convertfrom. substring (0, 2 );
Switch (s)
{
Case "01": temp = 1; break;
Case "10": temp = 2; break;
Case "11": temp = 3; break;

}
}
}
If (temp! = 0)
{
Convertings = temp. tostring () + convertings;
}
Return convertings;
}