所以我有一个函数,我将 Func 回调传回。我还想添加某种选择投影以便能够对对象进行投影,这意味着我只会执行一个数据库调用。该函数看起来像这样:
public T Get<T>(string id, Func<T> getItemCallback) where T : class
{
item = getItemCallback();
if (item != null)
{
doSomeThing(item);
// Here I would like to call something else that is
// expecting a specific type. Is there way to pass in a
// dynamic selector?
doSomethingElse(item.Select(x => new CustomType { id = x.id, name = x.name }).ToList());
}
return item;
}
void doSomethingElse(List<CustomType> custom)
{
....
}
Leme 显示我目前如何调用它,这可能会有所帮助:
public List<MyDataSet> GetData(string keywords, string id)
{
return _myObject.Get(
id,
() => db.GetDataSet(keywords, id).ToList());
// Perhaps I could add another parameter here to
// handled the projection ????
}
多亏了 Reed,我才知道......看起来像这样:
public T Get<T>(string id, Func<T> getItemCallback, Func<T, List<CustomType>> selector) where T : class
{
item = getItemCallback();
if (item != null)
{
doSomething(item);
var custom = selector(item);
if (custom != null)
{
doSomethingElse(custom);
}
}
return item;
}
电话看起来像:
public List<MyDataSet> GetData(string keywords, string id)
{
return _myObject.Get(
id,
() => db.GetDataSet(keywords, id).ToList(),
x => x.Select(d => new CustomType { id = d.ReferenceId, name = d.Name })
.ToList());
}