DropDownList control in ASP.NET using VB.NET
In this article we will learn how to use DropDownList control in ASP. NET.
In this article we will learn how to use DropDownList control in ASP. NET.
DropDownList control:
-DropDownList Allows to select only one item from many items.
-Use Items collection to add the items.
-Each item is an object of ListItem class ListItem(string text, string value).
Properties:
Items - The collection of items in the list.
ID - Programmatic name of the control.
AutoPostBack - Automatically postback to the server after selection is changed.
AccessKey - keyboard shortcut used by the control.
DropDownList event:
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles DropDownList1.SelectedIndexChanged
End Sub
For example:
Drag a DropDownList, Button and TextBox control on the form. when we select the items in the DropDownList and click on the button its should be display on the Textbox control.
The form looks like this:
Figure 1.
Now double click on the form and add the below code.
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
For i As Integer = 1950 To DateTime.Now.Year
DropDownList1.Items.Add(New ListItem(i.ToString()))
Next
End If
End Sub
Use Page.IsPostBack property to check the post backs.
Now double click on the button control and add the following code.
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
TextBox1.Text = DropDownList1.SelectedItem.Text.ToString()
End Sub
Now save and run the application And click the DropDownList than DropDownList items will be display.
Figure 2.
Now select the items from the DropDownList then click on the button the selected items will be display on the TextBox.
Figure 3.