c# - Avoid excessive type-checking in generic methods? -

my question concerns type-checking in chain of generic methods. let's have extension method attempts convert byte array int, decimal, string, or datetime.

public static t read<t>(this bytecontainer ba, int size, string format) t : struct, iconvertible {     var s = string.concat(ba.bytes.select(b => b.tostring(format)).toarray());                 var magic = fromstring<t>(s);     return (t)convert.changetype(magic, typeof(t)); } 

this calls method called fromstring translates concatenated string specific type. unfortunately, business logic dependent on type t. end megalithic if-else block:

private static t fromstring<t>(string s) t : struct {     if (typeof(t).equals(typeof(decimal)))     {         var x = (decimal)system.convert.toint32(s) / 100;         return (t)convert.changetype(x, typeof(t));     }     if (typeof(t).equals(typeof(int)))     {         var x = system.convert.toint32(s);         return (t)convert.changetype(x, typeof(t));     }     if (typeof(t).equals(typeof(datetime)))         ... etc ...  } 

at point, prefer multiple methods same name , different return types, along lines of this:

// <wishfulthinking> private static decimal fromstring<t>(string s) {     return (decimal)system.convert.toint32(s) / 100; }     private static int fromstring<t>(string s) {     return system.convert.toint32(s); } // </wishfulthinking> 

... realize not valid, t can't constrained specific type, , without it, of methods have same conflicting signature.

is there feasible way implement fromstring without excessive type-checking? or might there better way approach problem altogether?

or might there better way approach problem altogether?

sure, there one: can make each converter lambda, make dictionary of them, , use them conversion, this:

private static idictionary<type,func<string,object>> converters = new dictionary<type,func<string,object>> {     {typeof(int), s => convert.changetype(system.convert.toint32(s), typeof(int))} ,   {typeof(decimal), s => convert.changetype((decimal)system.convert.toint32(s) / 100, typeof(decimal))} ,   ... // , on }; public static t read<t>(this bytecontainer ba, int size, string format) t : struct, iconvertible {     func<string,object> converter;     if (!converters.trygetvalue(typeof(t), out converter)) {         throw new argumentexception("unsupported type: "+typeof(t));     }     var s = string.concat(ba.bytes.select(b => b.tostring(format)).toarray());     return (t)converter(s); }