public static MetaObject Restrict(this MetaObject self, Type type)
{
ContractUtils.RequiresNotNull(self, "self");
ContractUtils.RequiresNotNull(type, "type");
IRestrictedMetaObject rmo = self as IRestrictedMetaObject;
if (rmo != null)
{
return(rmo.Restrict(type));
}
if (type == self.Expression.Type)
{
if (type.IsSealedOrValueType())
{
return(self);
}
if (self.Expression.NodeType == ExpressionType.New ||
self.Expression.NodeType == ExpressionType.NewArrayBounds ||
self.Expression.NodeType == ExpressionType.NewArrayInit)
{
return(self);
}
}
if (type == typeof(Null))
{
return(new MetaObject(
Expression.Constant(null),
self.Restrictions.Merge(Restrictions.GetInstanceRestriction(self.Expression, null)),
self.Value
));
}
if (self.HasValue)
{
return(new MetaObject(
AstUtils.Convert(
self.Expression,
CompilerHelpers.GetVisibleType(type)
),
self.Restrictions.Merge(Restrictions.GetTypeRestriction(self.Expression, type)),
self.Value
));
}
return(new MetaObject(
AstUtils.Convert(
self.Expression,
CompilerHelpers.GetVisibleType(type)
),
self.Restrictions.Merge(Restrictions.GetTypeRestriction(self.Expression, type))
));
}
public static DynamicMetaObject Restrict(this DynamicMetaObject self, Type type)
{
ContractUtils.RequiresNotNull(self, "self");
ContractUtils.RequiresNotNull(type, "type");
IRestrictedMetaObject rmo = self as IRestrictedMetaObject;
if (rmo != null)
{
return(rmo.Restrict(type));
}
if (type == self.Expression.Type)
{
if (type.IsSealed ||
self.Expression.NodeType == ExpressionType.New ||
self.Expression.NodeType == ExpressionType.NewArrayBounds ||
self.Expression.NodeType == ExpressionType.NewArrayInit)
{
return(self.Clone(self.Restrictions.Merge(BindingRestrictionsHelpers.GetRuntimeTypeRestriction(self.Expression, type))));
}
}
if (type == typeof(DynamicNull))
{
return(self.Clone(
AstUtils.Constant(null),
self.Restrictions.Merge(BindingRestrictions.GetInstanceRestriction(self.Expression, null))
));
}
Expression converted;
// if we're converting to a value type just unbox to preserve
// object identity. If we're converting from Enum then we're
// going to a specific enum value and an unbox is not allowed.
if (type.IsValueType && self.Expression.Type != typeof(Enum))
{
converted = Expression.Unbox(
self.Expression,
CompilerHelpers.GetVisibleType(type)
);
}
else
{
converted = AstUtils.Convert(
self.Expression,
CompilerHelpers.GetVisibleType(type)
);
}
return(self.Clone(converted, self.Restrictions.Merge(BindingRestrictionsHelpers.GetRuntimeTypeRestriction(self.Expression, type))));
}