Slide 12.5: Text boxes (cont.)

Text Boxes (Cont.)

Add a Script (Cont.)
In the following example we declare one TextBox control and one Label control in an .aspx file. The following method and properties of TextBox are used in the example:

OnTextChanged method, which gives the name of the function to be executed when the text in the textbox has changed

AutoPostBack property, which is used to set or return whether or not an automatic post back occurs when the user presses Enter or Tab in the TextBox control. If this property is set to TRUE the automatic post back is enabled, otherwise FALSE. Default is FALSE.

Text property, which gets or sets the text content of the TextBox control

When you change the value in the TextBox and either click outside the TextBox or press the Tab key, the change subroutine is executed. The change subroutine writes a text to the Label control:

demo_textbox3.aspx

Web

<%@ Page Language="C#" %>
<script language="C#" runat="server">
 protected void change( object sender, EventArgs e ) {
  lbl1.Text = "You changed text to " & txt1.Text;
 }
</script>

<html>
 <body> 
  <form runat="server">
   Change text
   <asp:TextBox id="txt1" runat="server" text="Hello World!"
      OnTextChanged="change" AutoPostBack="true"/>
   <p><asp:Label id="lbl1" runat="server" /></p>
  </form>
 </body>
</html>