Linq明显无法正常工作(Linq distinct not working correctly)

 我遇到了一个linq查询的奇怪问题。 我正在使用LINQPad 4进行一些使用LinqToSQL作为LinqPad驱动程序的正则表达式的查询。 
 
 这是我正在尝试的查询： 
 
(from match in
from s in SystemErrors
select Regex.Match(s.Description, "...")
select new 
{
  FamilyCode = match.Groups["FamilyCode"].Value,
  ProductPrefix = match.Groups["ProductPrefix"].Value,
  BillingGroup = match.Groups["BillingGroup"].Value,
  Debtor = match.Groups["Debtor"].Value
}).Distinct()
 
 正如您所看到的，我正在尝试使用组从日志表中的文本描述中提取数据。 查询有效，但Distinct不想工作，它返回所有Match的一行。 
 
 我已经读过，distinct应该使用匿名类型，匹配每个属性。 更奇怪的是，distinct确实做了一些事情，它通过FamilyCode（然后是ProductPrefix等）按字母顺序排序值。 
 
 有人知道为什么这不起作用？ 谢谢 
 
 以下是LinqPad的SQL选项卡中显示的内容： 
 
DECLARE @p0 NVarChar(1000) = 'Big Regexp'
DECLARE @p1 NVarChar(1000) = 'FamilyCode'
DECLARE @p2 NVarChar(1000) = 'ProductPrefix'
DECLARE @p3 NVarChar(1000) = 'BillingGroup'
DECLARE @p4 NVarChar(1000) = 'Debtor'

SELECT DISTINCT [t2].[Description] AS [input], [t2].[value], [t2].[value2], [t2].[value3], [t2].[value4], [t2].[value5]
FROM (
    SELECT [t1].[Description], [t1].[value], @p1 AS [value2], @p2 AS [value3], @p3 AS [value4], @p4 AS [value5]
    FROM (
        SELECT [t0].[Description], @p0 AS [value]
        FROM [SystemError] AS [t0]
        ) AS [t1]
    ) AS [t2]

I'm having a strange problem with a linq query. I'm using LINQPad 4 to make some a query that uses regular expression using LinqToSQL as the LinqPad driver.
 
Here's the query that I'm trying to make :
 
(from match in
from s in SystemErrors
select Regex.Match(s.Description, "...")
select new 
{
  FamilyCode = match.Groups["FamilyCode"].Value,
  ProductPrefix = match.Groups["ProductPrefix"].Value,
  BillingGroup = match.Groups["BillingGroup"].Value,
  Debtor = match.Groups["Debtor"].Value
}).Distinct()
 
As you can see I'm trying to extract data from a text description in a log table using groups. The query works, but the Distinct doesn't want to work, it returns a line for all Match.
 
I have read that distinct should work with anonymous type, matching each property. Even more strange is that distinct does actually do something, it orders the values alphabetically by the FamilyCode (and then by ProductPrefix, etc.).
 
Has someone an idea on why this isn't working? Thanks
 
Here is what is displayed in the SQL tab of LinqPad :
 
DECLARE @p0 NVarChar(1000) = 'Big Regexp'
DECLARE @p1 NVarChar(1000) = 'FamilyCode'
DECLARE @p2 NVarChar(1000) = 'ProductPrefix'
DECLARE @p3 NVarChar(1000) = 'BillingGroup'
DECLARE @p4 NVarChar(1000) = 'Debtor'

SELECT DISTINCT [t2].[Description] AS [input], [t2].[value], [t2].[value2], [t2].[value3], [t2].[value4], [t2].[value5]
FROM (
    SELECT [t1].[Description], [t1].[value], @p1 AS [value2], @p2 AS [value3], @p3 AS [value4], @p4 AS [value5]
    FROM (
        SELECT [t0].[Description], @p0 AS [value]
        FROM [SystemError] AS [t0]
        ) AS [t1]
    ) AS [t2]

原文：https://stackoverflow.com/questions/4441659