大约有 40,000 项符合查询结果（耗时：0.0465秒） [XML]
Random row from Linq to Sql
... select row).FirstOrDefault();
Note that this is only suitable for small-to-mid-size tables; for huge tables, it will have a performance impact at the server, and it will be more efficient to find the number of rows (Count), then pick one at random (Skip/First).
for count approach:
var qry...
How to use the CancellationToken property?
...t points where you can stop executing safely across loop body, and loop usually have some logical condition to exit (iterate over all items in collection etc.). So I believe it's better not to mix that conditions as they have different intention.
Cautionary note about avoiding CancellationToken.Thr...
How do Mockito matchers work?
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Mockito matchers are static methods and calls to those methods, which stand in for arguments during calls to when and verify.
Hamcrest matchers (archived version) (or Hamcrest-style matchers) are stateless, general-purpose object instances that implement Matcher<...
Why there is no ForEach extension method on IEnumerable?
...s done at runtime, ForEach() is at compile time (Big Plus!)
The syntax to call a delegate is indeed much simpler: objects.ForEach(DoSomething);
ForEach() could be chained: although evilness/usefulness of such a feature is open to discussion.
Those are all great points made by many people here and ...
Why do C++ libraries and frameworks never use smart pointers?
... their implementations.
But because of the lack of standard ABI, you generally cannot pass these objects safely across module boundaries. A GCC shared_ptr is probably different from an MSVC shared_ptr, which too can differ from an Intel shared_ptr. Even with the same compiler, these classes are not...
Eclipse - Unable to install breakpoint due to missing line number attributes
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The above didn't work for me. I had to click the 'Remove all Breakpoints' icon in the Eclipse > Breakpoints view, then re-add the breakpoints. That worked.
– Vik David
May 19 '11 at 14:05
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When should I use the Visitor Design Pattern? [closed]
...want to make the fewest possible modifications to it.
The Visitor pattern allows you to move each new operation in a suitable class, and you need to extend the hierarchy's interface only once. Let's do it. First, we define an abstract operation (the "Visitor" class in GoF) which has a method for ev...
Returning IEnumerable vs. IQueryable
...ecution.
The difference is that IQueryable<T> is the interface that allows LINQ-to-SQL (LINQ.-to-anything really) to work. So if you further refine your query on an IQueryable<T>, that query will be executed in the database, if possible.
For the IEnumerable<T> case, it will be L...
Difference between ObservableCollection and BindingList
...se I've used both to notify for any add/delete change in Source, but I actually do not know when to prefer one over the other.
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must appear in the GROUP BY clause or be used in an aggregate function
I have a table that looks like this caller 'makerar'
7 Answers
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