How to retrieve selected values for selected items

问题:

I'm populating a ListBox in a WinForms application, this way:

listBoxUsers.DataSource = ctx.Users.ToList();
listBoxUsers.DisplayMember = "Name";
listBoxUsers.ValueMember = "Id";

how to retrieve the selected Ids when I'm setting the SelectionMode to MultiSimple I want to do a foreach loop on them, like this:

foreach(var itemId in listBoxUsers.SelectedValues)//unfortunately not exist
{
    int id = int.Parse(itemId);
    // . . . 
}

回答1:

Since you know the type of items, you can use such code:

var selectedValues = listBox1.SelectedItems.Cast<User>().Select(x=>x.Id).ToList();

---

Side Note: The ListBox control lacks a GetItemValue method. A method which should work like GetItemText, but for getting values. In the linked post I shared an extension method to get the value from an item. Using that extension method you can get selected values independent from type of items:

var selectedValues = listBox1.SelectedItems.Cast<object>()
                             .Select(x => listBox1.GetItemValue(x)).ToList();

If for some reason you are interested to have a text representation for selected values:

var txt = string.Join(",", selectedValues);

回答2:

Have you tried with the SelectedItems property?

foreach (var item in listBoxUsers.SelectedItems)

{

}

回答3:

try this:

foreach (DataRowView item in listBoxUsers.SelectedItems)
            {
              int id=int.parse(item[0].ToString());
            }