sqltolinq，空值的判断

Question

    使用了sqltolinq，在图中的判断有个错误提示，该如何正确判断呢？    数字如何 和 null 值比较，要转换一下么？

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 1

Int以及任何值类型永远不可能等于null，因此你值得判断一个具体的数值，譬如：

pt.PropertyID!=0

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Answer 2

    这样的话，那我就真没办法来判断了，因为我就是要判断pt.PropertyID的值是否为空啊！pt.PropertyID在数据库中是个int类型的自增主键！

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 3

自增主键永远不可能为空。

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If you think one reply solves your problem, please mark it as An Answer, if you think someone's reply helps you, please mark it as a Proposed Answer

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