Web Control dropping Keystrokes

[Glenn Rosenthal]

Has anyone experienced this? I have a web control with a number of text boxes. When the user types into one of the text boxes, an occassional character will be dropped. It is not a specific character, or position; the characters are dropped at seemingly random moments. "AutoPostBa ck" is not set for any of these text boxes, and the control itself is not set for AutoPostBack either.

The code is written in Visual Studio 2003 C#.

[balabaster]

Do you have any javascript functioning on the window or on the textbox itself. Specifically do you handle keypress, keydown or keyup and inside of those events, do you have something like evt.handled = false set anywhere? These are the only reasons I can think that a keypress would be dropped. The autopostback shouldn't have any effect as this is handled when you focus out of the textbox. Oh, that leads me to another thought, If you *did* have AutoPostBack enabled on this control and you have any other objects trying to grab focus, then when the other control grabs focus, this one would be prompted to postback if the contents had changed when it lost focus. I'll keep thinking, but I think they're the most obvious answers off the top of my head.

[Glenn Rosenthal]

I will double-check (I have just inherited this code and problem this morning).

But at this point, I do not see any client-side code/scripting/what-have-you. I am really wondering what to look for when it is a control inside a page.

[balabaster]

I will double-check (I have just inherited this code and problem this morning).

But at this point, I do not see any client-side code/scripting/what-have-you. I am really wondering what to look for when it is a control inside a page.

Normally I would say that if it's literally dropping keystrokes (and of course it's a web application) then it must either be client side code issues (i.e. Javascript) or it must be an issue with the browser or client machine. Is this behaviour consistent across multiple clients or is it a single particular client that's noticing this behaviour?

[Glenn Rosenthal]

It really doesn't look like anything pertaining to client side coding; I've put in some tracers, and nothing seems to be firing during the data entry. My own theory is its the page containing the control.

[balabaster]

It really doesn't look like anything pertaining to client side coding; I've put in some tracers, and nothing seems to be firing during the data entry. My own theory is its the page containing the control.

If there's no javascript firing on the object nor is there any javascript set at the ASCX level that handles keypress/keydown/keyup, then that leaves the ASPX and any master pages to which the ASPX belongs. Load full page up in IE and do view source. Do a search for keypress, keydown and keyup and see if anything springs up. Keystrokes are handled client side, not server side, so there must be a client script somewhere -

embedded in the ASCX HTML code OR
dynamically added in the code behind for the ASCX OR
embedded in the ASPX HTML code OR
dynamically added in the code behind for the ASPX OR
... you get the picture

...check the ASCX, ASPX and Master pages. Don't forget to check the code behinds for each too. Realise also that a script can be attached to an object at runtime in Javascript without it being in the onlick, onkeypress, onkeydown, onkeyup properties of the object itself - for instance:

document.onload = function(){
  var elem = document.getElementById("MyElem")
 
  elem.onkeypress = function(event){
    //Do my bidding...
  }
}

This may be added at a higher level than the ASCX, but could still be attached to the object embedded inside. So just because it's not in a user control, doesn't mean it's not there...