Partial Class _Default
Inherits System.Web.UI.Page
Dim checkbox As CheckBox
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles form1.Load
checkbox = New CheckBox()
checkbox.Checked = False
checkbox.Text = "checkbox"
checkbox.Visible = True
div1.Controls.Add(checkbox)
End Sub
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
checkbox.Checked = True
End Sub
End Class
<form id="form1" runat="server">
<div id="div1" runat="server">
</div>
<asp:Button ID="Button1" runat="server" Text="Button" />
</form>