.net - How to maintain unique List Before Saving To Database? - C# -

a simplified scenario:

• i have list<foo>.
• foo has 2 properties description (string), isfoo (bool)

e.g:

var foos = new list<foo>(); 

user can "add new foo's" via textboxes, on form submit this:

foos.add(new foo { description = txtone.text, isfoo = true }); foos.savetodb(); 

however, there multiple textboxes, , if example type "foobar" in textbox one, "foobar" in textbox two, do not want show error, not want add them collection. (don't worry reason behind this, simplified scenario).

i don't need show ui, when submit form, before persisting database need remove duplicates (or prevent them being added list in first place).

what's easiest/best way this? dictionary perhaps?

i'm using c#4, linq, .net 4.

you can use hashset<foo>.

hashsets unique, unordered collections.
adding element exists silently nothing. (and return false)

note must override equals , gethashcode on foo class compare value.

also note hashsets intrinsically unordered; if care insertion order, can't use it.

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alternatively, can use linq check whether list has duplicate:

if (!foos.any(f => f.description == txtone.text))     foos.add(new foo { description = txtone.text, isfoo = true });