C# 程序员最常犯的 10 个错误

矫情吗；* 2022-08-22 01:23 254阅读 0赞

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     <h2 style="margin:0px 0px 10pt; padding:0px 0px 5px; font-size:14pt; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(204,204,204)"> <a style="color:rgb(51,102,153)" rel="nofollow"></a>#5常见错误：在LINQ语句之中没有考虑底层对象</h2> 
     <p style="margin-top:0px; margin-bottom:5pt; padding-top:0px; padding-bottom:0px"> 对于处理抽象操纵集合任务，LINQ无疑是庞大的。无论他们是在内存的对象，数据库表，或者XML文档。在如此一个完美世界之中，你不需要知道底层对象。然而在这儿的错误是假设我们生活在一个完美世界之中。事实上，相同的LINQ语句能返回不同的结果，当在精确的相同数据上执行时，如果该数据碰巧在一个不同的格式之中。</p> 
     <p style="margin-top:0px; margin-bottom:5pt; padding-top:0px; padding-bottom:0px"> 例如，请考虑下面的语句：</p> 
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        <span style="margin:0px; padding:0px"><a href="http://www.oschina.net/translate/top-10-mistakes-that-c-sharp-programmers-make#" style="color:rgb(160,160,160)!important; text-decoration:none!important; margin:0px!important; padding:1px 0px 0px!important; outline:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; overflow:visible!important; position:static!important; right:auto!important; text-align:center!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; min-height:auto!important; display:block!important; background:none!important" rel="nofollow">?</a></span> 
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            <div style="margin:0px!important; padding:0px 1em!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; min-height:auto!important; white-space:pre!important; background:none rgb(248,248,248)!important"> 
             <code style="white-space:nowrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; min-height:auto!important; background:none!important">decimal&nbsp;total=(from&nbsp;accout&nbsp;in&nbsp;myaccouts</code> 
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             <code style="white-space:nowrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; min-height:auto!important; background:none!important">where&nbsp;accout.status==‘active"</code> 
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             <code style="white-space:nowrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; min-height:auto!important; background:none!important">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
             <code style="white-space:nowrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; min-height:auto!important; background:none!important">select&nbsp;accout&nbsp;.Balance).sum();</code> 
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     <p style="margin-top:0px; margin-bottom:5pt; padding-top:0px; padding-bottom:0px"> 想象一下，该对象之一的账号会发生什么。状态等于“有效的”（注意大写A)?</p> 
     <p style="margin-top:0px; margin-bottom:5pt; padding-top:0px; padding-bottom:0px"> 好吧，如果myaccout是Dbset的对象。（默认设置了不同区分大小写的配置），where表达式仍会匹配该元素。然而，如果myaccout是在内存阵列之中，那么它将不匹配，因此将产生不同的总的结果。</p> 
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