Check if string has bigger value

[AceInfinity]

string tfile = System.IO.File.ReadAllText(@"test.txt").Trim();
string var = "test";
if (Convert.ToDouble(tfile) > Convert.ToDouble(var))
{
}
else if (Convert.ToDouble(tfile) < Convert.ToDouble(var))
{
}
else //Equal
{
}

Maybe you want to use a TryParse to avoid throwing exceptions too?