Keypress event on ASP.NET TextBox control

Question

Hell all,

 

I am developing application in ASP.NET, the challenges arise when my user enter data's into the asp:TextBoxes  as the TextBox loses focus a Summary TextBox sum all the datae before saving.

if their is a wrong entry in some of the asp:TextBoxes, since asp;TextBoxes only allow _TextChanged event therefore any change made on the TextBoxes will not affect the summary TextBox, i tried the following trick:

 

<asp:Panel ID="Panel3" runat="server" DefaultButton="Button3">

<asp:Button ID="Button3" runat="server" Text="Button" Style="display:none" OnClick="Button3_Click" />

<asp:TextBox ID="TextBox24" runat="server" Width="52px" AutoPostBack="True" OnTextChanged="TextBox24_TextChanged"></asp:TextBox>

</asp:Panel>

this work once sine then it not working again.

 

can anyone help please.......?