WPF listbox control

Avuya Mxoli

Hi all,

I have 2listboxes and two buttons. I am trying to move items between these listboxes using buttons. I want to avoid adding the same items more than once to any of the listboxes and here is what I am using which is not working. It just keeps adding and ignores the if statement.

if(listbox2.Items.Contains(listbox1.Items) == true)
{
MessageBox.Show("Items already added");
}
else
{
foreach(var item in listbox1.Items)//Adds ALL items that are in the listbox
{
listbox2.Items.Add(item);
}

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
Accepted answer
Try:

for(int i = 0; i {
if (!listBox2.Items.Contains(listBox1.Items[i])) listBox2.Items.Add(listBox1.Items[i]);
}

listBox1.Items.Clear(); // if you want to move rather than just copy
Vulpes14y ago
Incidentally, you could make your MessageBox a bit more interesting by listing the duplicated items:

var duplicateList = new List();

for(int i = 0; i {
if (!listBox2.Items.Contains(listBox1.Items[i]))
{
listBox2.Items.Add(listBox1.Items[i]);
}
else
{
duplicateList.Add(listBox1.Items[i].ToString());
}
}

listBox1.Items.Clear();

if (duplicateList.Count > 0)
{
MessageBox.Show("Duplicates of the following items have been removed:\r\n\r\n" + String.Join("\r\n", duplicateList.ToArray()));
}
Avuya Mxoli14y ago
Thank you Vulpes, you have been a great help to me and hopefully others who will see this will find it as helpful
Vulpes14y ago
Something like this perhaps:

bool duplicateItems = false;

for(int i = 0; i
{
if (!listBox2.Items.Contains(listBox1.Items[i]))
{
listBox2.Items.Add(listBox1.Items[i]);
}
else
{
duplicateItems = true;
}
}

listBox1.Items.Clear();

if (duplicateItems)
{
MessageBox.Show("Warning: the duplicated item(s) have been removed");
}
Avuya Mxoli14y ago
Thank you so much Vulpes that worked perfectly. Now I tried adding an else so that it does not just stop and do nothing...for my user's sake I want to show a message box that says Items have already been added but when I add the else the message box keeps popping up because it's inside the for loop. How can I do this more efficiently?
Avuya Mxoli14y ago
Priya I dont think you understood my question. I am adding ALL listbox items not "selectedItem".Please look at the question again
Satyapriya Nayak14y ago
Hi Avuya,

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 WindowsFormsApplication1

{



    public partial class Form1 : Form
    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)
        {

            listBox1.Items.Add("Raj");

            listBox1.Items.Add("Raj");

            listBox1.Items.Add("Raju");

            listBox1.Items.Add("Rahul");

            listBox1.Items.Add("Harry");

            listBox1.Items.Add("Ben");

            listBox1.Items.Add("Ian");

        }





        private void btn_right_Click(object sender, EventArgs e)
        {

            if (listBox2.Items.Contains(listBox1.SelectedItem) == true)
            {

                MessageBox.Show("Item Exits");

            }

            else

            {

                listBox2.Items.Add(listBox1.SelectedItem);

                int i = 0;
                i = listBox1.SelectedIndex;

                listBox1.Items.RemoveAt(i);

            }

        }

        private void btnleft_Click(object sender, EventArgs e)
        {

            listBox1.Items.Add(listBox2.SelectedItem);

            int i = 0;

            i = listBox2.SelectedIndex;

            listBox2.Items.RemoveAt(i);

        }

    }

}

Thanks