Вопрос о Стиле C# действия/делегата
Для Таблицы:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<table>';
Для Столбца:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<table>' AND
REFERENCED_COLUMN_NAME = '<column>';
В основном, мы изменили REFERENCED_TABLE_NAME с REFERENCED_COLUMN_NAME в где пункт.
5 ответов
Neither 1 or 2. A third option is the winner
public event EventHandler<NumberChangedEventArgs> NumberChanged;
You're breaking a number of style guidelines for developing in C#, such as using a type for event args that doesn't extend EventArgs.
Yes, you can do it this way, as the compiler doesn't care. However, people reading your code will do a WTF.
Не создавайте новый тип, если вам это не нужно. Я думаю, что это лучше:
public event Action<object, double> OnNumberChanged;
Причина, по которой существуют семейства делегатов Action и Func , заключается в том, чтобы служить именно этой цели и уменьшать потребность в создании новых типов делегатов разработчиками.
Typically I stick to using an EventArgs derived class as the argument. It makes the code much more consistent.
I have a class:
public class ApplyClickedEventArgs : EventArgs
{
...
}
and a handler:
void cpy_ApplyClicked(object sender, ApplyClickedEventArgs e)
{
...
}
The declaration is:
public event EventHandler<ApplyClickedEventArgs> ApplyClicked;
I think option 1 is better if I were to choose, but IIRC, the official guidelines for events state that your second parameter has to be a class with the name XxxEventArgs, and should have EventArgs up in its inheritance chain.
As with all questions about coding style. Pick the one you prefer, or that your team prefers, and keep it consistent throughout the project. As long as everyone who needs to can read it efficiently you will be fine.