Prevent Key from Displaying in Textbox in ASP.Net

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How to write script which respond on each key pressed for text box and prevent from displaying a particular key in Textbox in ASP.NET

Posted 14-Jul-11 3:11am

Vijay Vishwakarmar

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3 solutions

Solution 3

For example, this is how to filter all characters but digits:

HTML

<html>
   <head>
      <script type="text/javascript"><!--
         function filterDigits(eventInstance) { 
            eventInstance = eventInstance || window.event;
                key = eventInstance.keyCode || eventInstance.which;
            if ((47 < key) && (key < 58) || key = 45 || key == 8) {
               return true;
            } else {
               if (eventInstance.preventDefault)
                  eventInstance.preventDefault();
               eventInstance.returnValue = false;
               return false;
            } //if
         } //filterDigits
      --></script>
   </head>
<body">

<input type="text" onkeypress="filterDigits(event)"/>

</body>
</html>

Pay attention that you also have to allow #8 (backspace).

—SA

Posted 14-Jul-11 11:46am

Sergey Alexandrovich Kryukov

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walterhevedeich · Accepted Answer · 2011-07-14T03:21:00

Solution 1

You can handle the KeyPress[^] event in JavaScript.

Posted 14-Jul-11 3:21am

walterhevedeich

Pete O'Hanlon · Accepted Answer · 2011-07-14T03:21:00

Solution 2

You need to use JavaScript to handle this. I would typically look at using jQuery to make this functionality a lot easier, then you would hook up like this:

JavaScript

$(document).ready(function() {
  $('#allTextBoxesToWatch').keypress(function(ev) { 
    if (ev.which == 13)
      ev.preventDefault();
  });
});

In this example (which I've just typed from memory, so I apologise if it isn't 100% exact), it binds all textboxes that have a class of allTextBoxesToWatch to the keypress event. It then determines whether or not the user pressed the key with an ascii value of 13, and prevents the default action if it does.

Posted 14-Jul-11 3:21am

Pete O'Hanlon

Comments

Vijay Vishwakarmar 14-Jul-11 9:25am

Thanks for the reply but you please describe it in detail.

Pete O'Hanlon 14-Jul-11 9:38am

I've just given you the code for it. How much more detail do you expect?

Vijay Vishwakarmar 14-Jul-11 9:45am

Complete example with one textbox having keypress event and suspending a particular key

[no name] 14-Jul-11 9:49am

The examples should be more than enough for anyone to come up with their own code. There's no spoon-feeding here.

Pete O'Hanlon 14-Jul-11 10:37am

Well said.

Pete O'Hanlon 14-Jul-11 10:05am

Forget it. I have more important things to do with my time than write your bloody code for you. I've told you how the code works, and shown you where you'd put the key press event. I've even told you how to hook up to the textboxes. It's now your turn to actually do something for yourself.