Ho una pagina di prova,
codice:
Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs) handles CheckBox1.CheckedChanged
 TextBox1.text = "Check changed"
 'msgbox("Chk Changed")
 response.write("changed")
 exit sub
End Sub

Sub Button1_Click(sender As Object, e As EventArgs)
response.write(textbox1.text)
 response.write("Click")
exit sub
end sub

End Sub
ed il codice completo è:
codice:
<%@ Page Language="VB" %>
<%@ Register TagPrefix="wmx" Namespace="Microsoft.Matrix.Framework.Web.UI" Assembly="Microsoft.Matrix.Framework, Version=0.6.0.0, Culture=neutral, PublicKeyToken=6f763c9966660626" %>
<%@ import Namespace=" System.Diagnostics" %>
<script runat="server">

    ' Insert page code here
    '
    
    
    
    Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs) handles CheckBox1.CheckedChanged
     TextBox1.text = "Check changed"
     'msgbox("Chk Changed")
     response.write("changed")
     exit sub
    End Sub
    
    Sub Button1_Click(sender As Object, e As EventArgs)
    response.write(textbox1.text)
    response.write("btn click")
    exit sub
    end sub
    
   
</script>
<html>
<head>
</head>
<body>
    <form runat="server">
        


            <asp:TextBox id="TextBox1" runat="server" ToolTip="ciao"></asp:TextBox>
            <asp:CheckBox id="CheckBox1" runat="server" OnCheckedChanged="CheckBox1_CheckedChanged" Text="Check Box"></asp:CheckBox>
            <asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Cliccami"></asp:Button>
        </p>
        


            
        </p>
        


              </p>
        
    </form>
</body>
</html>
Succede questo, che al cambiamento della checkbox nn accade nulla, ma se premo il pulsante allora si scatena anche l'evento checkchanged(se è stato cambiato) altrimenti se cambio lo stato del checkbox nn accade nulla, perchè?