为什么在将项目添加到组合框中时值相同并且没有循环增加？

Question

ComboboxItem boxitem = new ComboboxItem();

        public Form1()
        {
            InitializeComponent();

            for (int i = 0; i < 100; i++)
            {

                boxitem.Text = i.ToString();
                comboBox1.Items.Add(boxitem);
            }
        }

And the class ComboboxItem :

public class ComboboxItem
        {
            public string Text { get; set; }
            public object Value { get; set; }

            public override string ToString()
            {
                return Text;
            }
        }

But for some reason all the items in the comboBox1 are 99 There are 100 items all of them the same 99 Instead 1 2 3 4 5 6 7 .... 99

Answer 1

Here you are setting the text of the same ComboBox item over and over and adding it to your list:

for (int i = 0; i < 100; 
{
    boxitem.Text = i.ToString();
    comboBox1.Items.Add(boxitem);
}

Instead, create a new ComboBox inside the loop and add that to the list. Just move the

ComboboxItem boxitem = new ComboboxItem();

inside your for-loop, and you're good.

Answer 2

it is that you are changing the text of a single item, instead of instantiating a new one with each iteration. This should fix it:

ComboboxItem boxitem = new ComboboxItem();

    public Form1()
    {
        InitializeComponent();

        for (int i = 0; i < 100; i++)
        {
            //added bit follows here
            boxitem = new ComboboxItem();
            boxitem.Text = i.ToString();
            comboBox1.Items.Add(boxitem);
        }
    }