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Adding and Removing Items from a Windows Forms ComboBox, ListBox, or CheckedListBox Control

Visual Studio .NET 2003

Items can be added to a Windows Forms combo box, list box, or checked list box in a variety of ways, since these controls can be bound to a variety of data sources. However, this topic demonstrates the simplest method and assumes 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's ToString method.

To add items

  • Add the string or object to the list by using the Add method of the ObjectCollection class. The collection is referenced using the Items property:
    ' Visual Basic
    ComboBox1.Items.Add("Tokyo")
    
    // C#
    comboBox1.Items.Add("Tokyo");
    
    // C++
    comboBox1->Items->Add(S"Tokyo");
    

    - or -

  • Insert the string or object at the desired point in the list with the Insert method:
    ' Visual Basic
    CheckedListBox1.Items.Insert(0, "Copenhagen")
    
    // C#
    checkedListBox1.Items.Insert(0, "Copenhagen");
    
    // C++
    checkedListBox1->Items->Insert(0, S"Copenhagen");
    

    - or -

  • Assign an entire array to the Items collection:
    ' Visual Basic
    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)
    
    // C#
    System.Object[] ItemObject = new System.Object[10];
    for (int i = 0; i <= 9; i++)
    {
       ItemObject[i] = "Item" + i;
    }
    listBox1.Items.AddRange(ItemObject);
    
    // C++
    System::Object* ItemObject[] = new System::Object*[10];
    for (int i = 0; i <= 9; i++)
    {
       ItemObject[i] = String::Concat(S"Item", i.ToString());
    }
    listBox1->Items->AddRange(ItemObject);
    

To remove an item

  • Call the Remove or RemoveAt method to delete items.

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

    ' Visual Basic
    ' 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")
    
    // C#
    // 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");
    
    // C++
    // 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(S"Tokyo");
    

To remove all items

  • Call the Clear method to remove all items from the collection:
    ' Visual Basic
    ListBox1.Items.Clear()
    
    // C#
    listBox1.Items.Clear();
    
    // C++
    listBox1->Items->Clear();
    

See Also

ComboBox Class | ListBox Class | CheckedListBox Class| Sorting the Contents of a Windows Forms ComboBox, ListBox, or CheckedListBox Control | When to Use a Windows Forms ComboBox Instead of a ListBox | Windows Forms Controls Used to List Options

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