我有一个类,它有一个执行一些数据库操作的方法
我想允许在用于数据库访问的方法调用中发送现有(打开)上下文
但是,如果没有发送上下文,我会创建一个新的上下文。
我只想确保对象在包含在方法调用中时不会被丢弃。
当调用的方法中使用了using作用域时,对象是否已被释放?
// DbService class
class DbService
{
private void SomeDbAction(SomeDbContextObject backendContext = null)
{
using (var context = backendContext ?? CreateNewContextObject())
{
// Some actions using the context
}
}
}
// Call from another class
class Temp
{
void DoSomeThing()
{
var existingContext = new SomeDbContextObject();
dbService.SomeDbAction(existingContext);
// Is dbService disposed here?
UseContextForSomethingElse(existingContext);
}
}
// Is dbService disposed here?
是的,它被处理掉了。在这种情况下,可选参数对你不利——最好有两个特定的重载:
class DbService
{
public void SomeDbAction(SomeDbContextObject backendContext)
{
// Some actions using the context
}
public void SomeDbAction()
{
using (var context = CreateNewContextObject())
{
SomeDbAction(context);
}
}
}
如果backendContext
对象已传入,则不应处置该对象,但如果在方法中创建了,则应处置该对象
private void CoreSomeDbAction(SomeDbContextObject backendContext) {
//TODO: Some actions using the context
}
private void SomeDbAction(SomeDbContextObject backendContext = null) {
if (null == backendContext) {
// created context should be disposed
using (SomeDbContextObject context = new SomeDbContextObject(...)) {
CoreSomeDbAction(context);
}
}
else
CoreSomeDbAction(backendContext); // passed context should be prevent intact
}