How to: Add and Remove Items from a Windows Forms ComboBox, ListBox, or CheckedListBox Control

Items can be added to a Windows Forms combo box, list box, or checked list box in a variety of ways, because these controls can be bound to a variety of data sources. However, this topic demonstrates the simplest method and requires no data binding. The items displayed are usually strings; however, any object can be used. The text that is displayed in the control is the value returned by the object'sToStringmethod.

To add items

1. Add the string or object to the list by using the Add method of the ObjectCollection class. The collection is referenced using theItemsproperty:

   ComboBox1.Items.Add("Tokyo")
   

   comboBox1.Items.Add("Tokyo");
   

   comboBox1.get_Items().Add("Tokyo");
   

   comboBox1->Items->Add("Tokyo");
   

   - or -

2. Insert the string or object at the desired point in the list with theInsertmethod:

   CheckedListBox1.Items.Insert(0, "Copenhagen")
   

   checkedListBox1.Items.Insert(0, "Copenhagen");
   

   checkedListBox1.get_Items().Insert(0, "Copenhagen");
   

   checkedListBox1->Items->Insert(0, "Copenhagen");
   

   - or -

3. Assign an entire array to theItemscollection:

   Dim ItemObject(9) As System.Object
   Dim i As Integer
      For i = 0 To 9
      ItemObject(i) = "Item" & i
   Next i
   ListBox1.Items.AddRange(ItemObject)
   

   System.Object[] ItemObject = new System.Object[10];
   for (int i = 0; i <= 9; i++)
   {
      ItemObject[i] = "Item" + i;
   }
   listBox1.Items.AddRange(ItemObject);
   

   System.Object[] ItemObject = new System.Object[10];
   for(int i=0;i <= 9;i ++)
   {
      ItemObject .set_Item( i , "Item" + i );
   }
   listBox1.get_Items().AddRange(ItemObject);
   

   Array<System::Object^>^ ItemObject = gcnew Array<System::Object^>(10);
   for (int i = 0; i <= 9; i++)
   {
      ItemObject[i] = String::Concat("Item", i.ToString());
   }
   listBox1->Items->AddRange(ItemObject);
   

To remove an item

• Call theRemoveorRemoveAtmethod to delete items.

  Remove has one argument that specifies the item to remove.RemoveAtremoves the item with the specified index number.

  ' To remove item with index 0:
  ComboBox1.Items.RemoveAt(0)
  ' To remove currently selected item:
  ComboBox1.Items.Remove(ComboBox1.SelectedItem)
  ' To remove "Tokyo" item:
  ComboBox1.Items.Remove("Tokyo")
  

  // To remove item with index 0:
  comboBox1.Items.RemoveAt(0);
  // To remove currently selected item:
  comboBox1.Items.Remove(comboBox1.SelectedItem);
  // To remove "Tokyo" item:
  comboBox1.Items.Remove("Tokyo");
  

  // To remove item with index 0:
  comboBox1.get_Items().RemoveAt(0);
  // To remove currently selected item:
  comboBox1.get_Items().Remove(comboBox1.get_SelectedItem());
  // To remove "Tokyo" item:
  comboBox1.get_Items().Remove("Tokyo");
  

  // To remove item with index 0:
  comboBox1->Items->RemoveAt(0);
  // To remove currently selected item:
  comboBox1->Items->Remove(comboBox1->SelectedItem);
  // To remove "Tokyo" item:
  comboBox1->Items->Remove("Tokyo");
  

To remove all items

• Call the Clear method to remove all items from the collection:

  ListBox1.Items.Clear()
  

  listBox1.Items.Clear();
  

  listBox1.get_Items().Clear();
  

  listBox1->Items->Clear();
  

See Also

Tasks

How to: Sort the Contents of a Windows Forms ComboBox, ListBox, or CheckedListBox Control

Reference

ComboBox
ListBox
CheckedListBox

Concepts

When to Use a Windows Forms ComboBox Instead of a ListBox

Other Resources

Windows Forms Controls Used to List Options