blocks|key|1829764|text|第二个例子读起来更好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1829765|不要认为在Distinct()之后需要.ToList()。|1829766|希望这能有所帮助|1829767|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

The second example reads better.

Don't think you need the .ToList() after Distinct().

Hope that helps

blocks|key|1829844|text|在IEnumerable<T>上(如本例所示)，您是对的，因为OrderBy是一种稳定的排序方法(参见Enumerable.OrderBy：此方法执行一种稳定的排序；也就是说，如果两个元素的键相等，则元素的顺序将保持不变。)，因此对于具有相同键的元素，其先前的顺序将保持不变。在IQueryable<T>上，这是不能保证的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1829845|var+allRoles+=+roles.Table
++++.AsEnumerable().Select(p+=>+new+FirmRole
++++{
++++++++Code+=+p.Field<string>("RoleName"),
++++++++Name+=+p.Field<string>("RoleName")
++++}).Distinct()
++++++.OrderBy(x+=>+x.Item.Code.StartsWith("f"))+
++++++.ToList();|code-block|syntax|javascript|1829846|请注意，您不需要二次排序，因为正如我所说的，OrderBy是稳定的。|1829847|Speedwise:你必须对小集合和大集合进行基准测试。OrderBy应为O(nlogn)，但按true/false排序(如本例所示)可能更类似于O(n)|1829848|entityMap|0|LINK|mutability|MUTABLE|url|https://msdn.microsoft.com/en-us/library/vstudio/bb534966%2528v=vs.100%2529.aspx^0|1|E|V|7|3V|D|1F|I|0|0|0|M|7|0|S|7|11|8|1C|4|1H|5|21|4|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

On <code>IEnumerable&lt;T&gt;</code> (as is in this case) you are right, because <code>OrderBy</code> is a stable sorting (see <a href="https://msdn.microsoft.com/en-us/library/vstudio/bb534966%28v=vs.100%29.aspx" rel="nofollow">Enumerable.OrderBy</a>: This method performs a stable sort; that is, if the keys of two elements are equal, the order of the elements is preserved., so for elements with the same key, their previous ordering is maintained. On <code>IQueryable&lt;T&gt;</code> this isn't guaranteed.

<pre><code>var allRoles = roles.Table
 .AsEnumerable().Select(p =&gt; new FirmRole
 {
 Code = p.Field&lt;string&gt;("RoleName"),
 Name = p.Field&lt;string&gt;("RoleName")
 }).Distinct()
 .OrderBy(x =&gt; x.Item.Code.StartsWith("f")) 
 .ToList();
</code></pre>

Note that you don't need a secondary ordering, because <code>OrderBy</code> is, as I've said, stable.

Speedwise: you'll have to benchmark it with small and big sets. An <code>OrderBy</code> should be <code>O(nlogn)</code>, but an ordering by <code>true</code>/<code>false</code> (as in this case) is probably more similar to <code>O(n)</code>

blocks|key|5614758|text|您应该使用GroupBy和ToLookup来获得您想要的结果。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5614759|++++++++var+allRoles+=+roles.Table
++++++++++++.AsEnumerable().Select(p+=>+new+FirmRole
++++++++++++{
++++++++++++++++Code+=+p.Field<string>("RoleName"),
++++++++++++++++Name+=+p.Field<string>("RoleName")
++++++++++++}).GroupBy(x+=>+x.StartsWith("f")).ToLookup(g+=>+g.Key);;

++++++++var+formRoles+=+allRoles[true].ToList();
++++++++var+otherRoles+=+allRoles[false].ToList();|code-block|syntax|javascript|5614760|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You should use GroupBy and ToLookup to get the results that you are looking for.

<pre><code> var allRoles = roles.Table
 .AsEnumerable().Select(p =&gt; new FirmRole
 {
 Code = p.Field&lt;string&gt;("RoleName"),
 Name = p.Field&lt;string&gt;("RoleName")
 }).GroupBy(x =&gt; x.StartsWith("f")).ToLookup(g =&gt; g.Key);;

 var formRoles = allRoles[true].ToList();
 var otherRoles = allRoles[false].ToList();
</code></pre>

blocks|key|4146469|text|我相信您可以实现一个基于IComparer<T>接口的自定义排序比较类，以提供所需的自定义排序：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4146470|public+class+CustomSortComparer+:+IComparer<string>
++++{
++++++++public+int+Compare(string+x,+string+y)
++++++++{
++++++++++++StringComparer+sc+=+StringComparer.CurrentCultureIgnoreCase;

++++++++++++if+(string.IsNullOrEmpty(x)+%7C%7C+string.IsNullOrEmpty(y))
++++++++++++{
++++++++++++++++return+sc.Compare(x,+y);
++++++++++++}

++++++++++++if+(x.StartsWith("f",+StringComparison.CurrentCultureIgnoreCase)+&&+
++++++++++++++++!y.StartsWith("f",+StringComparison.CurrentCultureIgnoreCase))
++++++++++++{
++++++++++++++++return+1;
++++++++++++}

++++++++++++if+(y.StartsWith("f",+StringComparison.CurrentCultureIgnoreCase)+&&+
++++++++++++++++!x.StartsWith("f",+StringComparison.CurrentCultureIgnoreCase))
++++++++++++{
++++++++++++++++return+-1;
++++++++++++}

++++++++++++return+sc.Compare(x,+y);
++++++++}
++++}+|code-block|syntax|javascript|4146471|然后打电话给：|4146472|var+allRoles+=+roles.Table
++++++.AsEnumerable().Select(p+=>+new+FirmRole
++++++{
++++++++++Code+=+p.Field<string>("RoleName"),
++++++++++Name+=+p.Field<string>("RoleName")
++++++}).OrderBy(x+=>+x.Code,+new+CustomSortComparer()).ToList();|4146473|entityMap^0|C|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

I believe that you can implement a custom sort comparison class based on the <code>IComparer&lt;T&gt;</code> interface for providing the required custom sorting:

<pre><code>public class CustomSortComparer : IComparer&lt;string&gt;
 {
 public int Compare(string x, string y)
 {
 StringComparer sc = StringComparer.CurrentCultureIgnoreCase;

 if (string.IsNullOrEmpty(x) || string.IsNullOrEmpty(y))
 {
 return sc.Compare(x, y);
 }

 if (x.StartsWith("f", StringComparison.CurrentCultureIgnoreCase) &amp;&amp; 
 !y.StartsWith("f", StringComparison.CurrentCultureIgnoreCase))
 {
 return 1;
 }

 if (y.StartsWith("f", StringComparison.CurrentCultureIgnoreCase) &amp;&amp; 
 !x.StartsWith("f", StringComparison.CurrentCultureIgnoreCase))
 {
 return -1;
 }

 return sc.Compare(x, y);
 }
 } 
</code></pre>

And then call:

<pre><code>var allRoles = roles.Table
 .AsEnumerable().Select(p =&gt; new FirmRole
 {
 Code = p.Field&lt;string&gt;("RoleName"),
 Name = p.Field&lt;string&gt;("RoleName")
 }).OrderBy(x =&gt; x.Code, new CustomSortComparer()).ToList();
</code></pre>

I have the following code. which is based on using a temp container to select specific items and then add them at the end of the list.

<pre><code> var allRoles = roles.Table
 .AsEnumerable().Select(p =&gt; new FirmRole
 {
 Code = p.Field&lt;string&gt;("RoleName"),
 Name = p.Field&lt;string&gt;("RoleName")
 })ToList();

 var formRoles = allRoles.Where(p =&gt; p.Code.StartsWith("f")).ToList();
 var otherRoles = allRoles.Except(formRoles).ToList();

 otherRoles.AddRange(formRoles);
</code></pre>

Would it be a better way to shorten this code and get rid of the temp list?

Something like 

<pre><code> var allRoles = roles.Table
 .AsEnumerable().Select(p =&gt; new FirmRole
 {
 Code = p.Field&lt;string&gt;("RoleName"),
 Name = p.Field&lt;string&gt;("RoleName")
 }).OrderBy(x=&gt;x.Code.StartsWith("f")).ThenBy(a=&gt;a);
</code></pre>

How to use LINQ to sort custom items by using StartWith

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有以下代码。这基于使用临时容器来选择特定项，然后将它们添加到列表的末尾。 var allRoles = roles.Table .AsEnumerable().Select(p => new FirmRole { Code = p.Field<string>("RoleName"...

问如何使用StartWith对自定义项进行排序
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问如何使用StartWith对自定义项进行排序EN