不支持错误

发布于 2024-11-13 12:46:31 字数 1034 浏览 3 评论 0原文

我有一个接受日期 dtSince 和字符串 component 作为参数的方法。我需要编写一个单行 linq 查询，用于搜索 dtSince 之前发生的条目，并且属于组件 component （如果指定）。我已尝试以下操作：

var result = from items in MyAzureTable
             where items.Occured >= dtSince
             && items.Component == (component ?? items.Component)
             select items;

但我收到了 NotSupported 错误。我猜 items.Component == (component ?? items.Component) 是问题所在。

如前所述，component 可以为 null 或为空。但我无法在原始查询中排除这一点，因为 this:

var result = from items in MyAzureTable
             where items.Occured >= dtSince
             select items;

可能会返回超过 1000 行（这似乎是 Azure 表的默认限制），因此我稍后无法使用 组件 对其进行过滤。如果我执行如下操作，我可能要查找的条目位于第 1001 行。因此，它不会给出我正在查找的结果。

if (!String.IsNullOrEmpty(component))
{
    result = result.Where(x => x.Component == component).ToList<>();
}

问题：是否可以有一个单行 linq 查询，可以在在 where 子句中使用它之前先检查非空字符串？

原文

I have a method that accepts a date dtSince and a string component as parameters. I need to write an one-line linq query that searches for entries that occurred before dtSince and is of Component component (if specified). I have tried the following:

var result = from items in MyAzureTable
             where items.Occured >= dtSince
             && items.Component == (component ?? items.Component)
             select items;

But I'm getting a NotSupported error. I guess the items.Component == (component ?? items.Component) is the problem.

As mentioned, component can be null or empty. But I cannot exclude that in the original query, because this:

var result = from items in MyAzureTable
             where items.Occured >= dtSince
             select items;

might return more than 1000 rows (which appears to be the default limit of Azure tables) and therefore I cannot filter it with the component later. If I do something like the below, the entry I might be looking for is at row 1001. Thus, it won't give me the result I am looking for.

if (!String.IsNullOrEmpty(component))
{
    result = result.Where(x => x.Component == component).ToList<>();
}

Question: Is it possible to have a one line linq query that can check for a non-empty string first before using it in a where clause?

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绝情姑娘 2024-11-20 12:46:31

试试这个：

var result = from items in MyAzureTable
             where items.Occured >= dtSince && 
                   (component == null || items.Component == component)
             select items;

Try this:

var result = from items in MyAzureTable
             where items.Occured >= dtSince && 
                   (component == null || items.Component == component)
             select items;

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