User defined table in Entity Framework generating incorrect query

Question

I Think I am currently experiencing a bug in Entity Framework 6 and possibly ADO.NET. Since there is a deadline I am not sure I can wait for this bug to be fixed and hopefully someone can help me with a clean work around.

The problem is that the query uses the values 1 and 5 in places where it should be 0.01 and 0.05. However weirdly enough 0.1 seems to be working

The generated query currently is:(gotten from SQL Server Profiler)

declare @p3  dbo.someUDT
insert into @p3 values(NULL,5)
insert into @p3 values(5,0.10)
insert into @p3 values(NULL,1)
insert into @p3 values(1,2)

exec sp_executesql N'Select * from @AName',N'@AName  [dbo].[someUDT] READONLY',@AName=@p3

While the correct code would be:

declare @p3  dbo.someUDT
insert into @p3 values(NULL,0.05)
insert into @p3 values(0.05,0.10)
insert into @p3 values(NULL,0.01)
insert into @p3 values(0.01,0.02)

exec sp_executesql N'Select * from @AName',N'@AName  [dbo].[someUDT] READONLY',@AName=@p3

I already created an issue on github here : User defined table inserting wrong value

I want to use a user defined table in my parameterized query, this question explains how this is done : Entity Framework Stored Procedure Table Value Parameter

This is the C# code used to get the SQL code above

DataTable dataTable = new DataTable();
dataTable.Columns.Add("value1", typeof(decimal));
dataTable.Columns.Add("value2", typeof(decimal));

dataTable.Rows.Add(null,0.05m); 
dataTable.Rows.Add(0.05m,0.1m); 
dataTable.Rows.Add(null,0.01m); 
dataTable.Rows.Add(0.01m,0.02m); 
List<SqlParameter> Parameters = new List<SqlParameter>();

Parameters.Add(new SqlParameter("@AName", SqlDbType.Structured) { Value = dataTable , TypeName= "dbo.someUDT" });

dbContext.Database.ExecuteSqlCommand("Select * from @AName", Parameters.ToArray());

And SQL code to get the user defined table

CREATE TYPE [dbo].[someUDT] AS TABLE
(
   [value1] [decimal](16, 5) NULL,
   [value2] [decimal](16, 5) NULL
)

EDIT:
Gert Arnold figured it out. Based on his answer I found an existing report here SQL Server Profiler TextData Column handles Decimal Inputs Incorrectly

Answer 1

It's a weird Sql Profiler artifact. The values are transferred correctly. I can demonstrate that by creating a database with your user-defined type and one little table:

CREATE TABLE [dbo].[Values](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Value] [decimal](16, 5) NOT NULL,
 CONSTRAINT [PK_Values] PRIMARY KEY CLUSTERED ([Id] ASC) ON [PRIMARY]
GO

And inserting a couple of values:

Id          Value
----------- ---------------------------------------
1           10.00000
2           1.00000
3           0.10000
4           0.01000

Then I run your code, slightly adapted:

DataTable dataTable = new DataTable();
dataTable.Columns.Add("value1", typeof(decimal));
dataTable.Columns.Add("value2", typeof(decimal));

dataTable.Rows.Add(0.001m, 0.03m);
List<SqlParameter> Parameters = new List<SqlParameter>();

Parameters.Add(new SqlParameter("@AName", SqlDbType.Structured) { Value = dataTable, TypeName = "dbo.someUDT" });

using(var context = new MyContext(connStr))
{
    var query = "Select v.Id from dbo.[Values] v, @AName a "
        + " where v.Value BETWEEN a.value1 AND a.value2";
    var result = context.Database.SqlQuery<int>(query, Parameters.ToArray());
}

(MyContex is just a class inheriting from DbContext and nothing else)

There is only one value between 0.001m and 0.03m and that's exactly what the query returns: 4.

However, Sql Server profiler logs this:

declare @p3 dbo.someUDT
insert into @p3 values(1,3) -- See here: the log is warped

exec sp_executesql N'Select v.Value from dbo.[Values] v, @AName a  where v.Value BETWEEN a.value1 AND a.value2',N'@AName [dbo].[someUDT] READONLY',@AName=@p3

And in SSMS that returns record #2.

I think it has to do with regional settings and decimal separators getting mixed up with decimal group separators somewhere in the logging.