How to: Remove an item from a List<string>

Question

How to: Remove an item from a List

I have got the following code snippet...

companies.Remove(listView_Test.SelectedItem.ToString());

There is a listView that contains (let's say) 3 items without a name, just with a Content of "A", "B" and "C". Now when I select an item of that listView, I secondly click on a button, which runs my method containing Remove()/RemoveAt(). Now I want to delete the line of the List<string> myList where the line is same to the Content of the selected item.

Edit: Solution by Flow Flow OverFlow

int index = companies.IndexOf(companyContent);
companies.RemoveAt(index);

Solution 1

You have to get the index of the object you wanna remove from the list, then you can:

//Assuming companies is a list 
companies.RemoveAt(i);

To get the index of the item you can use :

companies.IndexOf("Item");

or use a for loop with conditional statements:

for (int i = 0; i < companies.Count; i++) {
   // if it is List<String>
   if (companies[i].equals("Something")) {
         companies.RemoveAt(i);   
   }
}

Solution 2

You could either remove the item by its known position or by the contents in the item.

public static void Main()
{
    List<Object> items = new List<Object>();
    items.Add("test1");
    items.Add("test2");
    items.Add("test3");

foreach(var a in items)
    Console.WriteLine(a.ToString());
Console.WriteLine("--");

items.RemoveAt(1); // remove object at position 1, in this case "test2"

foreach(var a in items)
    Console.WriteLine(a.ToString());
Console.WriteLine("--");

items.RemoveAll(x => ((string) x) == "test1"); // LAMBDA query to remove by a condition

foreach(var a in items)
    Console.WriteLine(a.ToString());
}

Output

test1
test2
test3
--
test1
test3
--
test3

Solution 3

public int FindItem(List<string> haystack, string needle)
{ for (int i = 0; i < haystack.Count; i++) 
      if (haystack[i] == needle) return i;
  return -1;
}


try {
     companies.Remove(FindItem(companies, listView_Test.SelectedItem.ToString() ) );
    } catch {  /* not found, no problem.. */ } 

Comments

[sjantke]

What do you mean by "index of the object"? I do not know its position if you mean that. It is somewhere in the List<string>, I just know the "name". It is like "delete * from myList where Content = 'Hello World'".

[Dhaval Patel]

I think you have to cover RemoveRange also

[sjantke]

Thanks, that's what I'd like to do.

[Tobia]

If you remove an item during the iterations the list size/count changes and the i < companies.Count condition doesn't guarantee to check all the list. Please try with a list of two removable items: {"Something","Something"}

[Amos Egel]

@Tobia So, would it be better to loop through the list in backward order, like for (int i=(companies.Count-1); i>=0; i--)?

[Tobia]

Yes, it can be a solution.