Instance Method インスタンスメソッド

validateValue:forKey:error:

Returns a Boolean that indicates whether the value specified by a given pointer is valid for the property identified by a given key.

Declaration 宣言 

- (BOOL)validateValue:(inout id  _Nullable *)ioValue 
               forKey:(NSString *)inKey 
                error:(out NSError * _Nullable *)outError;

Parameters パラメータ

ioValue

A pointer to a new value for the property identified by inKey. This method may modify or replace the value in order to make it valid.

inKey

The name of one of the receiver's properties. The key must specify an attribute or a to-one relationship.

outError

If validation is necessary and ioValue is not transformed into a valid value, upon return contains an NSError object that describes the reason that ioValue is not a valid value.

Return Value 戻り値

A Boolean set to YES if the value pointed at by ioValue is valid for the property identified by inKey, or if the method is able to modify the value at ioValue to make it valid; otherwise NO.

Discussion 解説

The default implementation of this method searches the class of the receiver for a validation method whose name matches the pattern validate<Key>:error:. If you define such a method for a property, the default implementation of validateValue:forKey:error: calls it when asked to validate the corresponding property, allowing your method to alter the input value if needed, and to determine the return value.

If no such method exists for a particular property, validateValue:forKey:error: returns YES. In other words, by default, the general validation call succeeds if you don't explicitly provide a validation method for the given property.

See Adding Validation in Key-Value Coding Programming Guide for more information.

See Also 参照

Validation 検証

- validateValue:forKeyPath:error:
Returns a Boolean that indicates whether the value specified by a given pointer is valid for a given key path relative to the receiver.