Linq-to-SQL在where子句中连接两列

Question

I have a table set up like so:

prefix | value
 ABC     1234
 ABC     5678
 DEF     1234

Is it possible to create a linq query where prefix and value are concatenated for comparison in the where clause? I've tried this, but it always returns an empty set:

selected =
            from i in dc.items
            where i.prefix + i.value == "ABC1234"
            select i;

Edit: the following T-SQL comes up with the correct results:

 WHERE LTRIM(RTRIM([prefix])) + LTRIM(RTRIM([value])) = 'ABC1234'

Edit2: The following, which combines most of the answers below, still does not work:

where (String.Concat(i.prefix.Trim(), i.value.Trim())) == "ABC1234"

Edit3: So I've got it working, but I have no clue why. I've accepted an answer but if someone posts why it works I'd be grateful :)

This works (returns n rows):

var temp = dc.items.Where(i => i.prefix.Trim() + i.prefix.Trim() == "ABC1234");

This does not work (returns 0 rows):

var temp =
            from i in dc.items
            where i.prefix.Trim() + i.value.Trim() == "ABC1234"
            select i;

Answer 1

I dont's speak english. Try this:

var selected = dc.Where(x => x.prefix + x.value == "ABC1234");

Answer 2

Assuming that value is not a string, you could concatenate them like this:

var selected = dc.Items.Where(x => string.Concat(x.prefix, x.value) == "ABC1234");

The benefit to using string.Concat is that all of the arguments will be converted to string.

Answer 3

where (i.prefix + i.value) == "ABC1234"

Answer 4

Try to select this

selected =
 from c in db.items

 select new {

 Name = string.Format("{0}{1}", c.prefix , c.value)

};

and look will you have "ABC1234"