public Level NewLevel(Type aClass)
{
if (aClass == null)
{
throw new ArgumentNullException();
}
var classMetadata = new ClassMetadata(aClass);
if (!classMetadata.HasPublicConstructorWithZeroParameters())
{
Throw("Class '{0}' is missing a public constructor with zero args", aClass.Name);
}
if (!classMetadata.HasMethod("up"))
{
Throw("Class '{0}' is missing public instance method named 'Up'", aClass.Name);
}
if (!classMetadata.HasField("level"))
{
Throw("Class '{0}' is missing a public field named 'Level'", aClass.Name);
}
int? levelNumber = null;
Action upDelegate = null;
string description = string.Empty;
try
{
var instance = Activator.CreateInstance(aClass);
upDelegate = () => classMetadata.MethodInfo("up").Invoke(instance, null);
levelNumber = Convert.ToInt32(classMetadata.FieldInfo("level").GetValue(instance));
if (classMetadata.HasField("description"))
{
description = Convert.ToString(classMetadata.FieldInfo("description").GetValue(instance));
}
}
catch (TargetInvocationException ex)
{
var message = string.Format("Failed to create an instance of '{0}'. Check the code in the public constructor with zero args", aClass.Name);
throw new ArgumentException(message, ex);
}
return(new Level(levelNumber.Value, description, upDelegate));
}
