大约有 30,000 项符合查询结果（耗时：0.0505秒） [XML]
Sequence contains more than one element
...SingleOrDefault" - from what I can gather the OP is looking for a customer id which (I assume) should be unique, therefore, SingleOrDefault is actually more appropriate than FirstOrDefault. Also, this has actually raised a more serious problem with the OP's database design as it shows that it is pos...
How to create abstract properties in python abstract classes
...pass
The code now raises the correct exception:
Traceback (most recent call last):
File "foo.py", line 36, in
b1 = Base_1('abc')
TypeError: Can't instantiate abstract class Base_1 with abstract methods name
sha...
Create a GUID in Java
...
@angel Yes, it is theoretically possible for the UUID.randomUUID method to return a duplicate, but this is not at all a realistic concern. The Oracle/OpenJDK implementation uses a cryptographically-strong random number generator. Given that, and given...
jQuery select by attribute using AND and OR operators
...
AND operation
a=$('[myc="blue"][myid="1"][myid="3"]');
OR operation, use commas
a=$('[myc="blue"],[myid="1"],[myid="3"]');
As @Vega commented:
a=$('[myc="blue"][myid="1"],[myc="blue"][myid="3"]');
...
SQLite table constraint - unique on multiple columns
... adding UNIQUE(i, j) to the create statement is completely ignored on android. It creates the table, but leaves off the UNIQUE constraint. I was only able to do this by using an index.
– gattsbr
Aug 11 at 14:55
...
difference between each.with_index and each_with_index in Ruby?
...it simply adds a number to the index. When you check the index after your call, you will find it is unaffected. Good notes as usual, @sawa
– vgoff
Nov 28 '13 at 6:14
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Is there a `pointer-events:hoverOnly` or similar in CSS?
... it's easy enough to do in JQuery. Here's how I've done it:
HTML
<div
id="toplayer"
class="layer"
style="
z-index: 20;
pointer-events: none;
background-color: white;
display: none;
"
>
Top layer
</div>
<div id="bottomlayer" class="layer" style="z-index: 10"&g...
How to query as GROUP BY in django?
...ike aggregating lines_count=Count('lines'))).
Over a queryset qs you can call qs.query.group_by = ['field1', 'field2', ...] but it is risky if you don't know what query are you editing and have no guarantee that it will work and not break internals of the QuerySet object. Besides, it is an interna...
How to convert SSH keypairs generated using PuTTYgen (Windows) into key-pairs used by ssh-agent and
...Export OpenSSH and export your private key
Copy your private key to ~/.ssh/id_dsa (or id_rsa).
Create the RFC 4716 version of the public key using ssh-keygen
ssh-keygen -e -f ~/.ssh/id_dsa > ~/.ssh/id_dsa_com.pub
Convert the RFC 4716 version of the public key to the OpenSSH format:
ssh-keygen ...
CSS Input Type Selectors - Possible to have an “or” or “not” syntax?
...
CSS3 has a pseudo-class called :not()
input:not([type='checkbox']) {
visibility: hidden;
}
<p>If <code>:not()</code> is supported, you'll only see the checkbox.</p>
<ul...