public static object GetDefaultValue(this Type type)
{
if (type == typeof(DBNull))
{
return(DBNull.Value);
}
if (type == null || type.IsClass || type.IsInterface || type == typeof(Nullable <>) || TypeExtension.IsAssignableFrom(typeof(Nullable <>), type))
{
return(null);
}
if (type.IsEnum)
{
var attribute = (DefaultValueAttribute)Attribute.GetCustomAttribute(type, typeof(DefaultValueAttribute), true);
if (attribute != null && attribute.Value != null)
{
if (attribute.Value is string)
{
return(Enum.Parse(type, attribute.Value.ToString(), true));
}
else
{
return(Enum.ToObject(type, attribute.Value));
}
}
Array values = Enum.GetValues(type);
if (values.Length > 0)
{
return(System.Convert.ChangeType(values.GetValue(0), type));
}
}
return(System.Activator.CreateInstance(type));
}
public static object ConvertValue(object value, Type conversionType)
{
return(ConvertValue(value, conversionType, () => TypeExtension.GetDefaultValue(conversionType)));
}
public object Create(Type type, object argument, Func <ActivatorParameterDescriptor, bool> binder = null)
{
object result = null;
if (type.IsArray)
{
var elementType = type.GetElementType();
if (argument != null && argument is IEnumerable && result is IList)
{
var list = (IList)System.Activator.CreateInstance(typeof(List <>).MakeGenericType(elementType));
foreach (var entry in (IEnumerable)argument)
{
list.Add(Convert.ConvertValue(entry, elementType));
}
result = Array.CreateInstance(elementType, list.Count);
for (int i = 0; i < list.Count; i++)
{
((Array)result).SetValue(list[i], i);
}
return(result);
}
return(Array.CreateInstance(elementType, 0));
}
if (TypeExtension.IsAssignableFrom(typeof(IDictionary <,>), type))
{
var types = type.GetGenericArguments();
if (type.IsInterface)
{
result = System.Activator.CreateInstance(typeof(Dictionary <,>).MakeGenericType(types));
}
else
{
result = System.Activator.CreateInstance(type);
}
if (argument != null && result is IDictionary)
{
var entries = Collections.DictionaryExtension.ToDictionary((IEnumerable)argument);
foreach (var entry in entries)
{
((IDictionary)result).Add(
Convert.ConvertValue(entry.Key, types[0]),
Convert.ConvertValue(entry.Value, types[1]));
}
}
}
if (typeof(IDictionary).IsAssignableFrom(type))
{
if (type.IsInterface)
{
result = System.Activator.CreateInstance <Dictionary <object, object> >();
}
else
{
result = System.Activator.CreateInstance(type);
}
if (argument != null && result is IDictionary)
{
var entries = Collections.DictionaryExtension.ToDictionary((IEnumerable)argument);
foreach (var entry in entries)
{
((IDictionary)result).Add(entry.Key, entry.Value);
}
}
}
if (TypeExtension.IsAssignableFrom(typeof(ICollection <>), type))
{
var types = type.GetGenericArguments();
if (type.IsInterface)
{
result = System.Activator.CreateInstance(typeof(List <>).MakeGenericType(types));
}
else
{
result = System.Activator.CreateInstance(type);
}
if (argument != null && argument is IEnumerable && result is IList)
{
foreach (var entry in (IEnumerable)argument)
{
((IList)result).Add(Convert.ConvertValue(entry, types[0]));
}
}
}
if (typeof(IList).IsAssignableFrom(type))
{
if (type.IsInterface)
{
result = System.Activator.CreateInstance <List <object> >();
}
else
{
result = System.Activator.CreateInstance(type);
}
if (argument != null && argument is IEnumerable)
{
foreach (var entry in (IEnumerable)argument)
{
((IList)result).Add(entry);
}
}
}
if (typeof(ICollection).IsAssignableFrom(type))
{
if (type.IsInterface)
{
result = System.Activator.CreateInstance <List <object> >();
}
else
{
result = System.Activator.CreateInstance(type);
}
}
return(result);
}
