c# - I want to hide label whenever something is typed in text box in aspx page

I want to hide label, whenever something is typed in text box in aspx page.

I am trying something like this :

protected void txt_LastName_KeyPress(object sender, EventArgs e)
{
    Label_msg.Visible = false;
}
protected void txt_LastName_KeyDown(object sender, EventArgs e)
{
    Label_msg.Visible = false;
}

But it is not happening. Do I need to write something like this in focus event?

I want to hide label, whenever something is typed in text box in aspx page.

I am trying something like this :

protected void txt_LastName_KeyPress(object sender, EventArgs e)
{
    Label_msg.Visible = false;
}
protected void txt_LastName_KeyDown(object sender, EventArgs e)
{
    Label_msg.Visible = false;
}

But it is not happening. Do I need to write something like this in focus event?

Share Improve this question edited Oct 25, 2013 at 20:14 jltrem 12.6k4 gold badges43 silver badges50 bronze badges asked Oct 25, 2013 at 19:47 niru dyogi 6395 gold badges15 silver badges41 bronze badges

6 You can't do that. You need to use Javascript. – SLaks Commented Oct 25, 2013 at 19:49
1 Even if you could do what you wanted to do, it would be a performance nightmare in client-server web world, as you would be posting back to the server on every key press! :-( – Karl Anderson Commented Oct 25, 2013 at 19:57
Set Textbox's AutoPostBack Property to true – PaulShovan Commented Oct 25, 2013 at 20:09
@gypsyCoder: Insanity. – Joel Etherton Commented Oct 25, 2013 at 20:37
Javascript can help you on this purpose – PaulShovan Commented Oct 25, 2013 at 20:51

Add a ment |

7 Answers 7

Sorted by: Reset to default 4

You need javascript

Here is an implementation using jQuery

<script>
    $('#txt_LastName').focus(function() {
        $('#Label_msg').hide();
    });
    $('#txt_LastName').blur(function() {
        $('#Label_msg').show();
    });
</script>

A plain vanilla javascript solution would be

<script>
    document.getElementById("txt_LastName").onfocus = function() {
        document.getElementById("Label_msg").style.display = 'none';
    };
    document.getElementById("txt_LastName").onblur = function() {
        document.getElementById("Label_msg").style.display = 'inherit';
    };
</script>

This one may be helpful for you. Do as following...

Firstly, Set Textbox's AutoPostBack Property to true

AutoPostBack="True"

Then, Use OnTextChanged Event

protected void TextBox1_TextChanged(object sender, EventArgs e)
    {
        Label1.Visible = false;
    }

you can do some thing simple as below:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"     "http://www.w3/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3/1999/xhtml">
<head runat="server">
    <title></title>
    <script language="javascript" type="text/javascript">
        function hideOnKeyPress() {
            document.getElementById('lblHidden').style.display = 'none';
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="txtMaintCost" onkeypress="hideOnKeyPress(); return true;" runat="server"></asp:TextBox>
        <asp:Label ID="lblHidden" runat="server" Text="I'll hide when you type something in the text box" />
    </div>
    </form>
</body>
</html>

You can't change the visibility of a layer event based server side. You have to put this into a javascript procedure.

You have to possibilities: The easy way is, to use jQuery (you need to include jQuery!):

<script type="text/javascript">
$(function() {
    $('#txt_LastName').focus(function() {
        $('#Label_msg').hide();
    });
    $('#txt_LastName').blur(function() {
        $('#Label_msg').show();
    });
}
</script>

Second method: do it the hard way If you don't want to use jQuery for some reason, you have to work directly with the DOM. You can read about it there: W3Schools DOM Methods

You may want to look into a JavaScript MVVM library, such as KnockoutJS, like this:

<p>Your value: <input data-bind="value: someValue, valueUpdate: 'afterkeydown'" /></p>
<p>You have typed: <span data-bind="text: someValue"></span></p>

// Here's my data model
var viewModel = {
    someValue: ko.observable("edit me")
};

ko.applyBindings(viewModel); // This makes Knockout get to work

Here is a jsFiddle to illustrate how easy it is to achieve your desired key down functionality with JavaScript via KnockoutJS.

a simple javascript solution would be

HTML

<span id="one">text</span>
<input type="text" onkeypress="hide()" />

Javascript

var isHidden = false;
function hide(){
  if(!isHidden){
   isHidden = true; 
   document.getElementById("one").setAttribute("style","display:none");
  }
}

jsbin demo

Because there is no KeyPress Event in ASP.Net forms unlike Winforms you must use JQuery short hand code (for JavaScript) to handle hiding your label when user is typing in the textbox like this example:

<script>
    $(document).ready(function () {
        $("#txtUserName").keypress(function () {
            $("#lblUser").hide();
        });
    });
</script>

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c# - I want to hide label whenever something is typed in text box in aspx page - Stack Overflow

7 Answers 7

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