(Please Select), Smith, Bob Jones, Sue .. how remove comma after (Please Select) in LINQ?

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Ronald S. Cook - 28 Feb 2008 22:35 GMT

Hey guys,

The below code works fine, BUT appends a comma to my (Please Select).
Anybody know how I can get around this?

Thanks... and sorry is in VB.NET (I wish I was in C# on this project)... but
you guys are WAY more helpful than the VB forum.

Dim _Query As IEnumerable(Of Employee) = _
From e In dc.Employees _
Where e.Lookup.LookupCode <> "INA" _
Order By e.EmployeeLastName, _
e.EmployeeFirstName

Dim _Employee As New Employee()
_Employee.EmployeeLastName = "(Please Select)"
_Employee.EmployeeFirstName = ""
Dim _List As IList(Of Employee) = _Query.ToList()
_List.Insert(0, _Employee)

Dim _QueryWithSelect As IEnumerable = _
(From xyz In _List _
Select xyz.EmployeeId, _
EmployeeName = xyz.EmployeeLastName & ", " &
xyz.EmployeeFirstName).ToList()

Return _QueryWithSelect

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sloan - 28 Feb 2008 22:47 GMT

This is the C# group.

Either go with the

.general
or
.languages.vb

> Hey guys,
>
[quoted text clipped - 23 lines]
>
> Return _QueryWithSelect

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Jon Skeet [C# MVP] - 28 Feb 2008 23:24 GMT

> The below code works fine, BUT appends a comma to my (Please Select).
> Anybody know how I can get around this?

Sure. Currently you've got the following steps:

1) Build database query
2) Execute query and store results in list
3) Insert extra entry in list
4) Project list to strings
5) Convert to list
6) Return

Put step 3 after step 5 instead.

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Ronald S. Cook - 29 Feb 2008 01:37 GMT

Thanks John! And Sloan, I did try to first conver the code to C# but the
converters out there aren't up on converting LINQ yet.

Man, I sure wish this project was in C#... mostly for 1) nicer flow of
syntax, and 2) support resources out there... especially LINQ sample code!

>> The below code works fine, BUT appends a comma to my (Please Select).
>> Anybody know how I can get around this?
[quoted text clipped - 9 lines]
>
> Put step 3 after step 5 instead.

Reply to this Message

Ronald S. Cook - 29 Feb 2008 01:37 GMT

I mean't "Jon" not "John"... sorry.

>> The below code works fine, BUT appends a comma to my (Please Select).
>> Anybody know how I can get around this?
[quoted text clipped - 9 lines]
>
> Put step 3 after step 5 instead.

Reply to this Message

Ronald S. Cook - 29 Feb 2008 16:36 GMT

Hi Jon.. sorry to bother one last time, but I think I did something wrong
with your re-ordering recommendation.

With the re-ording below, the list is returned, but doesn't contain the
(Please Select) record. Any last idea how to squeeze it in?

'1) Build database query.
Dim _Query As IEnumerable(Of Employee) = _
From e In dc.Employees _
Where e.Lookup.LookupCode <> "INA" _
Order By e.EmployeeLastName, _
e.EmployeeFirstName

'2) Execute query and store results in list.
Dim _List As IList(Of Employee) = _Query.ToList()

'4) Project list to strings.
'5) Convert to list.
Dim _QueryWithSelect As IEnumerable = _
(From xyz In _List _
Select xyz.EmployeeId, _
EmployeeName = xyz.EmployeeLastName & ", " & xyz.EmployeeFirstName).ToList()

'3) Insert extra entry in list.
Dim _Employee As New Employee()
_Employee.EmployeeLastName = "(Please Select)"
_Employee.EmployeeFirstName = ""
_List.Insert(0, _Employee)

'6) Return.
Return _QueryWithSelect

Thanks!
Ron

>> The below code works fine, BUT appends a comma to my (Please Select).
>> Anybody know how I can get around this?
[quoted text clipped - 9 lines]
>
> Put step 3 after step 5 instead.

Reply to this Message

Jon Skeet [C# MVP] - 29 Feb 2008 16:46 GMT

> Hi Jon.. sorry to bother one last time, but I think I did something wrong
> with your re-ordering recommendation.
>
> With the re-ording below, the list is returned, but doesn't contain the
> (Please Select) record. Any last idea how to squeeze it in?

<snip>

> '3) Insert extra entry in list.
> Dim _Employee As New Employee()
> _Employee.EmployeeLastName = "(Please Select)"
> _Employee.EmployeeFirstName = ""
> _List.Insert(0, _Employee)

Currently you're adding the dummy record into the intermediate list
*after* you've converted the list. You need to add it to the resulting
(string) list instead.

This bottom line should be

_QueryWithSelect.Insert(0, "(Please Select)")

and _QueryWithSelect should be declared as a List(Of String).

Jon

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Ronald S. Cook - 29 Feb 2008 17:11 GMT

Thanks so much for the help, Jon. I made the changes you said (which make
sense), but then get this error:

Unable to cast object of type
'System.Collections.Generic.List'1[VB$AnonymousType_20'2[System.Guid,System]]'
to type System.Collections.Generic.IList'1[System.String]'.

Here is the code as I understand I should have it. I promise not to bother
you anymore!

'1) Build database query.
Dim _Query As IEnumerable(Of Employee) = _
From e In dc.Employees _
Where e.Lookup.LookupCode <> "INA" _
Order By e.EmployeeLastName, _
e.EmployeeFirstName

'2) Execute query and store results in list.
Dim _List As IList(Of Employee) = _Query.ToList()

'4) Project list to strings.
'5) Convert to list.
Dim _QueryWithSelect As IList(Of String) = _
(From xyz In _List _
Select xyz.EmployeeId, _
EmployeeName = xyz.EmployeeLastName & ", " & xyz.EmployeeFirstName).ToList()

'3) Insert extra entry in list.
_QueryWithSelect.Insert(0, "(Please Select)")

'6) Return.
Return _QueryWithSelect

>> Hi Jon.. sorry to bother one last time, but I think I did something wrong
>> with your re-ordering recommendation.
[quoted text clipped - 21 lines]
>
> Jon

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Jon Skeet [C# MVP] - 29 Feb 2008 19:05 GMT

> Thanks so much for the help, Jon. I made the changes you said (which make
> sense), but then get this error:
[quoted text clipped - 5 lines]
> Here is the code as I understand I should have it. I promise not to bother
> you anymore!

Ah, sorry, with the VB syntax I hadn't noticed that the projection was
to an anonymous type.

You'll need to create another instance of that anonymous type for the
"Please Select" entry, and make _QueryWithSelect implicitly typed. I
don't know how to do that in VB, I'm afraid.

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http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

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Ben Voigt [C++ MVP] - 06 Mar 2008 19:12 GMT

>> Thanks so much for the help, Jon. I made the changes you said
>> (which make sense), but then get this error:
[quoted text clipped - 12 lines]
> "Please Select" entry, and make _QueryWithSelect implicitly typed. I
> don't know how to do that in VB, I'm afraid.

Or just use Array.ConvertAll instead of Linq. Is there a new extension
method that makes ConvertAll available for a List perhaps?

Reply to this Message

Jon Skeet [C# MVP] - 06 Mar 2008 19:22 GMT

> > You'll need to create another instance of that anonymous type for the
> > "Please Select" entry, and make _QueryWithSelect implicitly typed. I
> > don't know how to do that in VB, I'm afraid.
>
> Or just use Array.ConvertAll instead of Linq. Is there a new extension
> method that makes ConvertAll available for a List perhaps?

List<T>.ConvertAll has been available since .NET 2.0. However, I don't
think that's the issue - the issue is adding the "(Please Select)"
*after* the projection to an anonymous type.

Signature

Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

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Ben Voigt [C++ MVP] - 06 Mar 2008 20:36 GMT

>> > You'll need to create another instance of that anonymous type for the
>> > "Please Select" entry, and make _QueryWithSelect implicitly typed. I
[quoted text clipped - 6 lines]
> think that's the issue - the issue is adding the "(Please Select)"
> *after* the projection to an anonymous type.

LINQ isn't helpful for the stringification, though, in this case.

IEnumerable<Employee> query = From e In dc.Employees Where
e.Lookup.LookupCode <> "INA" Order By e.EmployeeLastName,
e.EmployeeFirstName;
List<Employee> listEmp = New List<Employee>(query)
List<string> listStrings = listEmp.ConvertAll(e => e.EmployeeLastName + ", "
+ e.EmployeeFirstName);
listStrings.Insert(0, "(Please Select)");

Reply to this Message

Jon Skeet [C# MVP] - 06 Mar 2008 20:43 GMT

> >> > You'll need to create another instance of that anonymous type for the
> >> > "Please Select" entry, and make _QueryWithSelect implicitly typed. I
[quoted text clipped - 13 lines]
> e.EmployeeFirstName;
> List<Employee> listEmp = New List<Employee>(query)

That's more simply done with ToList() if you really need a list - but
you don't, here.

> List<string> listStrings = listEmp.ConvertAll(e => e.EmployeeLastName + ", "
> + e.EmployeeFirstName);
> listStrings.Insert(0, "(Please Select)");

But the point is that I was mistaken in my original assumption that
this was projecting to strings - it isn't. It's converting to a list of
anonymous type instances, which is why my original suggestion didn't
work.

However, if it *did* use strings, it could all be done without
ConvertAll:

var strings = Enumerable.Repeat("(Please Select)", 1)
.Concat(query.Select
(e => e.EmployeeLastName + ", " + e.EmployeeFirstName));

Signature

Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

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(Please Select), Smith, Bob Jones, Sue .. how remove comma after (Please Select) in LINQ?

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