Join

[shapper]

Hello,

I have a List<Role>, Roles, where Role has two properties: Type and
Description. Then I have: string [] MyRoles.

I need to define a CSV list created by all Desciptions of the
List<Rolewhich type is contained in string [] MyRoles.

string RolesCSV = Roles.Join(",", r =MyRoles.Contains(r.Type));

I get:
String[] does not contain a definition Contains.

.... But it is in the list as I right ...

What am I doing wrong?

Thanks,
Miguel

[Peter Duniho]

On Mon, 17 Nov 2008 10:45:11 -0800, shapper <md*****@gmail.comwrote:

I have a List<Role>, Roles, where Role has two properties: Type and
Description. Then I have: string [] MyRoles.

I need to define a CSV list created by all Desciptions of the
List<Rolewhich type is contained in string [] MyRoles.

string RolesCSV = Roles.Join(",", r =MyRoles.Contains(r.Type));

I get:
String[] does not contain a definition Contains.

... But it is in the list as I right ...

What am I doing wrong?

You're not showing enough code, for one. You're also not quoting the
exact compile error you got, for another.

That said, if the Type property of the Role class isn't of type string,
you may be getting an error that simply points out there's not an
appropriate overload of Contains(). Just because there's _a_ method of
that name doesn't mean it's a method that suits the parameters you tried
to pass in.

If that doesn't help you, you really should post a concise-but-complete
code sample that demonstrates the issue.

Pete

[Ignacio Machin ( .NET/ C# MVP )]

On Nov 17, 1:45*pm, shapper <[e-mail]:

Hello,

I have a List<Role>, Roles, where Role has two properties: Type and
Description. Then I have: string [] MyRoles.

I need to define a CSV list created by all Desciptions of the
List<Rolewhich type is contained in string [] MyRoles.

string RolesCSV = Roles.Join(",", r =MyRoles.Contains(r.Type));

I get:
String[] does not contain a definition Contains.

... But it is in the list as I right ...

What am I doing wrong?

Thanks,
Miguel

Hi,

IIRC Array does not have a member Contains, you cuold use Find
instead:
Roles.Select( (r)=MyRoles.Find(r)!=null)

[Jeroen Mostert]

shapper wrote:

I have a List<Role>, Roles, where Role has two properties: Type and
Description. Then I have: string [] MyRoles.

I need to define a CSV list created by all Desciptions of the
List<Rolewhich type is contained in string [] MyRoles.

string RolesCSV = Roles.Join(",", r =MyRoles.Contains(r.Type));

I get:
String[] does not contain a definition Contains.

Even if there were, you code makes no sense. .Contains() returns a boolean,
the .Join() method you're invoking doesn't take two arguments, and
..Description isn't anywhere.

Try

string RolesCSV = string.Join(",", (from r in Roles where
MyRoles.Contains(r.Type) select r.Description).ToArray());

If that still fails to compile, you need "using System.Linq;" at the top.

--
J.

[shapper]

On Nov 17, 7:39*pm, Jeroen Mostert <[e-mail]:

shapper wrote:

I have a List<Role>, Roles, where Role has two properties: Type and
Description. Then I have: string [] MyRoles.

I need to define a CSV list created by all Desciptions of the
List<Rolewhich type is contained in string [] MyRoles.

string RolesCSV = Roles.Join(",", r =MyRoles.Contains(r.Type));

I get:
String[] does not contain a definition Contains.

Even if there were, you code makes no sense. .Contains() returns a boolean,
the .Join() method you're invoking doesn't take two arguments, and
.Description isn't anywhere.

Try

* *string RolesCSV = string.Join(",", (from r in Roles where
MyRoles.Contains(r.Type) select r.Description).ToArray());

If that still fails to compile, you need "using System.Linq;" at the top.

--
J.

I am trying to use the following sintax:

string b = string.Join(", ", Roles.Where(r =MyRoles.Contains
(r.Type.ToString()) == true).Select(r =r.Description).ToArray());

Again I keep having the error:
'string[]' does not contain a definition for 'Contains' and the best
extension method overload 'MyApp.Mvc.ViewDataPaper.Contains
(System.Web.Mvc.ViewDataDictionary, System.Type)' has some invalid
arguments

And I can't find the method Find for MyRoles ... only Contains.

[Peter Duniho]

On Mon, 17 Nov 2008 13:21:16 -0800, shapper <md*****@gmail.comwrote:

I am trying to use the following sintax:

string b = string.Join(", ", Roles.Where(r =MyRoles.Contains
(r.Type.ToString()) == true).Select(r =r.Description).ToArray());

Again I keep having the error:
'string[]' does not contain a definition for 'Contains' and the best
extension method overload 'MyApp.Mvc.ViewDataPaper.Contains
(System.Web.Mvc.ViewDataDictionary, System.Type)' has some invalid
arguments

As I said, you need to post a concise-but-complete code example.

The error indicates that you have your own extension method declared
somewhere (in the MyApp.Mvc.ViewDataPaper class) by the name of
Contains(), and for some reason that's the one that chosen as the "best"
overload for the parameters you're passing. That particular overload
takes "System.Type", not "System.String" as an argument, and applies to
objects typed as "System.Web.Mvc.ViewDataDictionary" instead of
"System.Array" or (if you were using the LINQ extension method)
"IEnumerable<String>" (assuming "MyRoles" really is a String[], which
given the overload that the compiler believes is the best match is hardly
safe to assume at this point).

You cannot expect to get precise, useful answers if you don't bother to
post a concise-but-complete code example. All you're showing are tiny
little glimpses of code that is apparently changing from post to post.
There's no way to provide a definitive answer with that kind of input.

Pete