Insert Values Of All The Fields Into Variable?

I need to create a stored procedures, this procedure will receive two parameters:

@TableName

@KeyField

I need to storage into a variable the values of ALL THE FIELDS separeted by |

For example if my table is Customers

CustomerID CustomerName City

111 Adventure Boston

222 Pubs NY

And I execute EXEC mysp 'Customers',111

I need a return value like this

@ReturnValue = 111|Adventure|Boston

I create something like this

CREATE PROCEDURE my sp
@table varchar
@key numeric
AS
@field varchar(40),
@object int
Select @object = object_id from systables where name =@table

--The instructions to create a cursor

WHILE (@@FETCH_STATUS = 0 )
Select @object = name from sys.columns where object_id = @object

--The instructions to close and deallocate the cursor

I have alredy to save the value using the EXEC command but is not working; something like

@String = Select @object from @table where CustomerID = @keyValue