vb.net datatable.AsEnumerable 不起作用（基本示例）
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datatable.AsEnumerable doesn't work (basic example)
提问by user3496060
Dim x = From row In f_table.AsEnumerable()
Select row("Crop")
From what I understand, the "f_table.AsEnumerable" should make my search object ("row" in this case) a datarow object. This simple example runs without any exceptions but does not find any entries (This search works if I switch to an array of datarows that have been taken from f_table, in place of f_table.AsEnumerable).
据我了解，“f_table.AsEnumerable”应该使我的搜索对象（在本例中为“row”）成为数据行对象。这个简单的示例运行时没有任何异常，但没有找到任何条目（如果我切换到从 f_table 获取的数据行数组，而不是 f_table.AsEnumerable，则此搜索有效）。
Any ideas why AsEnumerable is not allowing for searching the rows of the table?
为什么 AsEnumerable 不允许搜索表的行的任何想法？
edited/added: The following is what I have, where "emptyrows" is a subset array of rows from f_table.
编辑/添加：以下是我所拥有的，其中“emptyrows”是 f_table 中行的子集数组。
Dim emptyrows_grouped = From row In emptyrows
Order By row("Date"), row("Time")
Group By New With {.date = row("Date")}.date,
New With {.crop = row("Crop")}.crop
Into Group
What i want is this form:
我想要的是这种形式：
Dim emptyrows_grouped = From row In f_table.AsEnumerable
Where row.Field(Of String)("SamplePosition") Like "Emp%"
Order By row("Date"), row("Time")
Group By New With {.date = row("Date")}.date,
New With {.crop = row("Crop")}.crop
Into Group
回答by OneFineDay
It works like this:
它是这样工作的：
Dim query = dt.AsEnumerable
.Where(Function(dr) dr("column name").ToString = "something").ToList
This yields a List of DataRows where this column has the value of "something"
这会产生一个 DataRows 列表，其中该列的值为“某物”
GroupBy:
通过...分组：
Dim query = dt.AsEnumerable
.Where(Function(dr) dr("column name").ToString = "something")
.GroupBy(Function(dr) dr("column name"))
回答by user3496060
Never mind - I'm a gigantic fool today because f_table is the wrong datatable. I used the right one and it worked.
没关系 - 今天我是个大傻瓜，因为 f_table 是错误的数据表。我使用了正确的方法，并且奏效了。
Dim emptyrows_grouped = From row In file_table.AsEnumerable
Where row.Field(Of String)("SamplePosition") ="Empty"
Order By row("Date"), row("Time")
Group By New With {.date = row("Date")}.date,
New With {.crop = row("Crop")}.crop
Into Group
Please excuse my wasting of your time!!
请原谅我浪费你的时间！！
