in C# I want to compare two Lists

Question

I have three lists

List1 < Labels > lbl and List2 < Strings > value and List3 < Strings > result

and I wanna compare both using foreach like

if (label1.text == value ) {  // value is the 2nd list name
 Label_Result.text = Result    // in third List
 Label1.font= new font("Tahoma",18);
 ListBox1.items.add(Label.text);
}

Edit ,,

I think what I need is three Lists

Possible duplicate of [Compare two Lists for differences](http://stackoverflow.com/questions/675699/compare-two-lists-for-differences) — hmnzr, May 16 '17 at 13:57
It looks like you're comparing a string to a List (your comment even points this out) — Gavin, May 16 '17 at 13:59
Are you going to compare the first string with the first label and so on? — Hossein Narimani Rad, May 16 '17 at 14:00

score 0 · Answer 1 · answered May 16 '17 at 14:05

Three basic examples. The first uses a simple nested foreach:

foreach(var item1 in list1)
    foreach(var item2 in list2)
        if(item1.text == item2)
        {
            //Do your thing
        {

You could reduce nesting by using LINQ. Note that you could make this considerably fancier in LINQ (you can join lists), but I've chosen a simpelr example to show you the basic idea.

foreach(var item1 in list1)
{
    var matchesInList2 = list2.Where(item2 => item1.text == item2);
    foreach(var match in matchesInList2)
    {
        //Do your thing
    }
}

There is a simpler way to approach it:

var matches = list1.Where(item1 => list2.Contains(item1.text));
foreach(var item1 in matches)
{
        //Do your thing, e.g.:
        //var theTextValue = item1.text;
}

To explain this simpler approach: we immediately filter list1, and only keep the elements whose .text value exists in list2.
After that, it is simply a matter of looping over the found matches, you don't need to filter anymore.

score -1 · Answer 2 · answered May 16 '17 at 14:01

-1

i think the best way is:

foreach(var list1item in lbl)  //List1 item
{
     foreach(var list2item in value) //List2 item
     {
       if(list1item == list2item)
       {
          //Do something
       }       
     }
}

answered May 16 '17 at 14:01

Moonfred

14
3

maybe you need to use a cast – Moonfred May 16 '17 at 14:03

in C# I want to compare two Lists

2 Answers2