public static object ExtractFirstConstant(Expression expression)
{
var visitor = new ConstantValueExtractor();
visitor.Visit(expression);
return(visitor.ConstantValue);
}
static void Main()
{
string name = "Michael";
Expression <Func <Person, object> > exp = p => p.FirstName == name;
var value = ConstantValueExtractor.ExtractFirstConstant(exp);
Console.WriteLine(value);
}