C# listbox exception

Arun Kurmi

hi,
if i remove an item from index 2 inn listbox and there is no item at index 2 i. e. only 2 item in listbox in index 0 and 1.then there is an exception.how handle it.

4 Replies

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Rajneesh Rai13y ago
Accepted answer
Hi Arun,
yes,if you try to remove item at index 2 (that does not exists)of listbox, you would get exception ArgumentOutOfRangeException. So keep item removal code in try catch block..
and check that the index exists or not in listbox i.e.

int index = index to remove;
if (index < lb.Items.Count)
lb.Items.RemoveAt(index);
Vulpes13y ago
If no item is selected in a ListBox, then its SelectedIndex property is equal to -1.

So, if the value of this property is not -1, it means that an item must be selected.
Arun Kurmi13y ago
Thanks,It is working but what are the meaning of this line: if (listBox1.SelectedIndex != -1)
Satyapriya Nayak13y ago
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication7
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }

        private void Form3_Load(object sender, EventArgs e)
        {
            listBox1.Items.Add("a");
            listBox1.Items.Add("a");
            listBox1.Items.Add("c");
        }

        private void button1_Click(object sender, EventArgs e)
        {

            if (listBox1.SelectedIndex != -1)
            {
                int i = 0;
                i = listBox1.SelectedIndex;
                listBox1.Items.RemoveAt(i);
            }

        }
    }
}