c# - How to extend string to deserialize binary data -

i'm using own extension method serialize strings (and more data types) file custom binary format (external, cannot modify format). method is:

public static byte[] serialize(this string str) {     if (str.length > short.maxvalue)         throw new argumentoutofrangeexception("str", "max length allowed " + short.maxvalue.tostring());     list<byte> data = new list<byte>();     data.add(0);     data.add(0);     if (str != null)     {         byte[] buffer = encoding.utf8.getbytes(str);         data.addrange(buffer);         data[0] = (byte)(buffer.length % 256);         data[1] = (byte)((buffer.length / 256) >> 8);     }     return data.toarray(); } 

an example of usage:

string str1 = "binary string"; byte[] data = str1.serialize(); 

result is

data = { 13, 0, 66, 105, 110, 97, 114, 121, 32, 83, 116, 114, 105, 110, 103 } 

now i'm trying add extension method deserialize when reading these files:

public static void deserialize(this string str, byte[] data) {     if (data == null || data.length < 2)     {         str = null;     }     else     {         short length = (short)(data[0] + (data[1] << 8));         if (data.length != length + 2)             throw new argumentexception("invalid data", "data");         str = encoding.utf8.getstring(data, 2, length);     } } 

if try this:

string str2 = null; str2.deserialize(data); 

the expected result str2 is

"binary string"

the actual result is

null

however, when debugging step step, str inside deserialize() gets correct value @ line str = encoding.utf8.getstring(data, 2, length);.

also tried this:

string str3 = string.deserialize(data); 

but not compile, , error message is

error 1 'string' not contain definition 'deserialize'

i don't know i'm doing wrong. idea on how solve it?

the first parameter of extension method object acting on. in case byte array data. return type wanting stuff string variable. therefore, signature deserialize method should be:

public static string deserialize(this byte[] data) 

also inside method need return string value full method should (note simplified slightly):

public static string deserialize(this byte[] data) {     if (data == null || data.length < 2)         return null;      short length = (short)(data[0] + (data[1] << 8));     if (data.length != length + 2)         throw new argumentexception("invalid data", "data");      return encoding.utf8.getstring(data, 2, length); } 

and use this:

string str1 = "binary string"; byte[] data = str1.serialize(); string str2 = data.deserialize();