刷新ComboBox项目，最简单的方法

Question

I've googled a lot. Found a lot as well. Unfortunately nothing is straight, easy and most importantly, simple. I want some guy write a method that takes a List<string> and removes previous Items , then set this List<string> .

Currently I have a method but it's not error free.

public void refreshList(List<string> list){
    albumList.Items.Clear();
    albumList.DataSource =  list;
}

Answer 1

For anyone still wondering.

You can use a BindlingList and BindingSource.

BindingList<YOUR_CLASS_TYPE> bindinglist = new BindingList<YOUR_CLASS_TYPE>()
BindingSource bSource = new BindingSource();
bSource.DataSource = bindinglist;
ComboBox.DataSource = bSource;

You add all items to your bindinglist and they will be automatically updated within your combobox.

If you want a sortable combobox you can construct the BindingList with a container that inherits from IList, like List that has a sort function. You can then sort that IList reference and it will be reflected again within the combobox.

Answer 2

You don't need albumList.Items.Clear();

This code works just fine

public void refreshList(List<string> list){
    albumList.DataSource =  list;
}

Answer 3

When bound to a data source, Items.Clear(); doesn't work. This should be:

albumList.DataSource = list;

or to be sure:

albumList.DataSource = null;
albumList.DataSource = list;

Answer 4

If you are using DataSource you need to clear items for the new list to appear. Since you can't clear while using DataSource you need to set it to null first.

albumList.DataSource = null;
albumList.Items.Clear();
albumList.DataSource = list;

Answer 5

I've been working on a task with a similar problem like this

The initial solution to set the datasource to null and to reassign the list back to it didn't work at all. Though it did clear the items and show up the new items in the list, it made selection of any of the items in that list impossible. But upon digging around the internet, I found an old VB solution that ended up working and having the intended effect.

Here's what you need to do:

1. Clear the list object before repopulating it. See code below:

    //adding the instantiation of the list object so you know what I'm clearing List<string> listExample = new List<string>(); listExample.Clear(); 

2. Refresh the comboBox, so that it picks up the new list. See code below:

    if (albumList.DataSource == null) { albumList.DataSource = listExample; } else { albumList.Refresh(); }