ComboBox

ComboBox is a combination of a TextBox and a ListBox. The ComboBox displays an editing field (TextBox) combined with a ListBox allowing us to select from the list or to enter new text. ComboBox displays data in a drop-down style format. The ComboBox class is derived from the ListBox class. Below is the Image of a ComboBox.

Notable properties of the ComboBox

The DropDownStyle property in the Appearance section of the properties window allows us to set the look of the ComboBox. The default value is set to DropDown which means that the ComboBox displays the Text set by it's Text property in the Textbox and displays it's items in the DropDownListBox below. Setting it to simple makes the ComboBox to be displayed with a TextBox and the list box which doesn't drop down. Setting it to DropDownList makes the ComboBox to make selection only from the drop down list and restricts you from entering any text in the textbox.

We can sort the ComboBox with it's Sorted property which is set to False by Default.

We can add items to the ComboBox with it's Items property.

ComboBox Event

The default event of ComboBox is SelectedIndexChanged which looks like this in code:

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object,_ ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged End Sub

Working with ComboBoxes

Drag a ComboBox and a TextBox control onto the form. To display the selection made in the ComboBox in the Textbox the code looks like this:

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object,_ ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged TextBox1.Text = ComboBox1.SelectedItem 'selecting the item from the ComboBox with selected item property End Sub

Removing items from a ComboBox

You can remove all items or one particular item from the list box part of the ComboxBox. Code to remove a particular item by it's Index number looks like this:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Button1.Click ComboBox1.Items.RemoveAt(4) 'removing an item by specifying it's index End Sub

Code to remove all items from the ComboBox

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Button1.Click ComboBox1.Items.Clear() 'using the clear method to clear the list box End Sub