十二星座古代身份贵族:GetEnvironmentVariable()可以赋值给IDictionary的对象吗？

IDictionary是个key/value的键值接口，GetEnvironmentVariable()又只能返回string的值，那它们之间可以传值吗？
public static void displayEnvironment()
{
IDictionary dict= Environment.GetEnvironmentVariable("username");
Console.WriteLine("there are {0} environment variables",dict.Count);

string[] keys=new string[dict.Count];
string[] values=new string[dict.Count];

int ix=0;
foreach(DictionaryEntry de in dict)
{
keys[ix]=(string) de.Key;
values[ix]=(string) de.Value;
++ix;
}

Array.Sort(keys,values);

for(ix=0;ix<keys.Length;++ix)
{
Console.Write("variable is {0} -- value? (y/n)",keys[ix]);
string rsp=Console.ReadLine();
if(rsp=="y"||rsp=="Y")
Console.WriteLine("\t==>{0}",values[ix]);
else Console.WriteLine();
}
}