Working with combox and listbox in WPF

Question

Hi all I have a combobox with cities and a listbox for customers. When I select a city I display all customers who stay there in my listbox. The problem is that when I select a city and the customers get loaded and I select the same city again it adds the customers again. Is there a way where I can avoid repeating items in a listbox? I hope this is clear thanks in advance

Satyapriya Nayak · Answer

Hi Avuya Try this... Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable{mso-style-name:Table Normal;mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-qformat:yes;mso-style-parent:;mso-padding-alt:0in 5.4pt 0in 5.4pt;mso-para-margin:0in;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Calibrisans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Times New Roman;mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:Times New Roman;mso-bidi-theme-font:minor-bidi;} 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 If this post helps you mark it as answer

Vulpes · Answer

Something like this perhaps: if (listBox1.SelectedIndex > -1 && !listBox2.Items.Contains(listBox1.SelectedItem)) { listBox2.Items.Add(listBox1.SelectedItem); }

Avuya Mxoli · Answer

Thanks Priya it works but only if I move them one by one. I have a button that moves listbox1 items to 2nd listbox all at the same time but here I cannot avoid adding all these items twice. It just doesnt work Im using this:if(lbx1.items.contains(lbox2.items) == true) { MessageBox.Show(Items exist); } it just skips the if statement...

Avuya Mxoli · Answer

Actually I realized I already sorted that out now what I want to know is if I add a 2nd listbox where items will be added from the 1st one how can I prevent adding duplicate items to the 2ns listbox. Example: I select a customer from listbox1 and add to listbox2 then I re-select the city from combobox and the customers get re-added to 1st listbox and the user selects a cusomer thats already in listbox2 and tries to add them again. How do I prevent this?

Vulpes · Answer

You need to clear the listbox's Items collection before loading the next set of customers: listBox1.Items.Clear();