Eliminates duplicate values from combo box

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• 

  Rajanikant Hawaldar6y agoPosted Oct 2, 2020, 10:30 PM

  Accepted answer

  Hey Jhaz, changed code check you was not checking combobox contains items before adding in timer tick event.

  1. using System;  
  2. using System.Collections.Generic;  
  3. using System.ComponentModel;  
  4. using System.Data;  
  5. using System.Drawing;  
  6. using System.Linq;  
  7. using System.Text;  
  8. using System.Threading.Tasks;  
  9. using System.Windows.Forms;  
  10. namespace WindowsFormsApp1  
  11. {  
  12. public partial class Form1 : Form  
  13. {  
  14. public Form1()  
  15. {  
  16. InitializeComponent();  
  17. }  
  18. private void timer1_Tick(object sender, EventArgs e)  
  19. {  
  20.      if(!comboBox1.Items.Contains("Duplicate"))  
  21.      {  
  22.           comboBox1.Items.Add("Duplicate");  
  23.      }  
  24. }  
  25. private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)  
  26. {  
  27. }  
  28. private void Form1_Load(object sender, EventArgs e)  
  29. {  
  30. comboBox1.Items.RemoveAt();  
  31. timer1.Start();  
  32. }  
  33. }  
  34. }  

   
• 

  Sachin Singh6y agoPosted Oct 2, 2020, 10:44 PM

  If you have already added duplicate values in combox and now want to remove them then following code is what you need

  1. var itemArry= ComboBox1.Items.SelectMany(i => i).Distinct().ToArray();  
  2. ComboBox1.Items.Clear();  
  3. ComboBox1.Items.AddRange(itemArry); 
     

   If you want to prevent duplicate entries then follow

   

  1. if(!comboBox1.Items.Contains("Duplicate"))    
  2.      {    
  3.           comboBox1.Items.Add("Duplicate");    
  4.      }