Develop Reference

User text input handling using TextBox

I have this control:
I'm trying to create a kind of validation, that whenever the user enters text to the TextBox, the "Add" button will be Enabled, and when the text is "" (null), the "Add" button is disabled.
I dont want to use validators.
here's the code:
protected void addNewCategoryTB_TextChanged(object sender, EventArgs e)
{
if (addNewCategoryTB.Text != "")
addNewCategoryBtn.Enabled = true;
else
addNewCategoryBtn.Enabled = false;
}
The problam is, that when the user enter's text, the "Add" button doesn't changes from disabled to enabled (and vice versa)...
any ideas?

Is it Web Forms? In Web Forms the TextChanged event of the TextBox won't fire by default.
In order to fire the event, you have to set the AutoPostBack property of the TextBox to true.
BUT, this would perform a HTTP post, what is kink of ugly, or you can wrap that in an UpdatePanel
A more elegant option, is to do that using jQuery, to do that in jQuery, you'll need some code like:
$(document).ready(function() {
$("#<%= yourTextBox.ClientID %>").change(function() {
var yourButton = $("#<%= yourButton.ClientID %>")
yourButton.attr('disabled','disabled');
yourButton.keyup(function() {
if($(this).val() != '') {
yourButton.removeAttr('disabled');
}
});
});
});

You'll need to accomplish this with Javascript, since ASP.NET is incapable of performing such client-side modifications. Think about it ... every time you pressed a letter inside the text box, it would have to postback and refresh the page in order to determine if the text box was empty or not. This is one way that ASP.NET differs from Winforms/WPF.

TextChanged events will make postback on server every time. You don't need to increase those request for such task.
You can use jquery to achieve this
var myButton = $("#btnSubmit");
var myInput=$("#name");
myButton.prop("disabled", "disabled");
myInput.change(function () {
if(myInput.val().length > 0) {
myButton.prop("disabled", "");
} else {
myButton.prop("disabled", "disabled");
}
});
JS Fiddle Demo
You just need to take care of elements Id when you are using Server Controls. For that Either you can use ClientID or set property ClientIdMode="Static"

Change page state with JavaScript, old state gets recalled on postback

Basically we have the "illusion" of an notification message box that exists as .Visible = false in the MasterPage. When it comes time to display a message in the box, we run a method that looks like this:
public static void DisplayNotificationMessage(MasterPage master, string message)
{
if (Master.FindControl("divmsgpanel") != null)
{
master.FindControl("divmsgpanel").Visible = true;
}
if (master.FindControl("divdimmer") != null)
{
master.FindControl("divdimmer").Visible = true;
}
TextBox thetxtbox = (TextBox)master.FindControl("txtboxmsgcontents");
if (thetxtbox != null)
{
thetxtbox.Text = message;
}
}
Basically through our designers awesome CSS voodoo, we end up with what appears to be a floating message box as the rest of the page appears dimmed out. This message box has a "Close" button to dismiss the "popup" and restore the dimmer, returning the site to the "normal" visual state. We accomplish this with JavaScript in the MasterPage:
function HideMessage() {
document.getElementById("<%# divmsgpanel.ClientID %>").style.display = 'none';
document.getElementById("<%# divdimmer.ClientID %>").style.display = 'none';
return false;
}
and the button's declaration in the .aspx page calls this HideMessage() function OnClientClick:
<asp:Button ID="btnmsgcloser" runat="server" Text="Close" style="margin: 5px;"
OnClientClick="return HideMessage()" />
The problem:
All future postbacks cause the MasterPage to "remember" the state of those divs from how they were before the HideMessage() JavaScript was executed. So in other words, every single postback after the initial call of the DisplayNotificationMessage() method causes the page to return to divmsgpanel.Visible = true and divdimmer.Visible = true, creating an endlessly annoying message box that incorrectly pops up on every postback.
The question:
Since we want the Close function to stay client-side JavaScript, how can we "notify" the page to stop reverting to the old state on postback, for just these two divs?

Can you try setting them to Visible = false in Master_Page Load event? It should hide them and reshow them just when you call DisplayNotificationMessage

Delete does not ask for confirmation

When Delete button is clicked, the confirmation box should pop up if the selected node has child nodes. Otherwise, it should not do anything.
Right now, when I click on delete, it just deletes without confirming.
Here is the code:
<asp:Button ID="btn_delete" runat="server" Height="32px"
onclick="btn_delete_Click" OnClientClick = "return childnode();"
Text="Delete" Visible="False" />
<script type="text/javascript">
function childnode() {
var treeViewData = window["<%=nav_tree_items.ClientID%>" + "_Data"];
var selectedNode = document.getElementById(treeViewData.selectedNodeID.value);
if (selectedNode.childNodes.length > 0) {
return confirm("heloo");
}
return false;
}
</script>

You'll need to return false from the function if you don't want the button push to go through in some cases. Currently you are only returning a value from the function when calling confirm.
If one or both of the if conditions fail, add a return false if you don't want the event to bubble up activating the button/sending the form.
Modification of your existing code
function childnode() {
var treeViewData = window["<%=nav_tree_items.ClientID%>" + "_Data"];
if (treeViewData.selectedNodeID.value != "") {
var selectedNode = document.getElementById(treeViewData.selectedNodeID.value);
if (selectedNode.childNodes.length > 0) {
return confirm("heloo");
}
return false; // don't send form
}
return false; // don't send form
}
Is it still malfunctioning?
Make sure that the logic inside your function is accurate, webbrowsers will often fail silently when trying to get a property of an undefined variable.
In your definition of your button you have written OnClientClick = "return childnode();", try changing this to OnClientClick="return childnode();" and see if that might solve the problem.
See if the event fires at all, OnClientClick="alert(123);".

Your function have return not in all of it's parts. Probably your function exists without confirm. Review your logic and decide what you want to do if one of your if statements not passed.

Change this:
onclick="btn_delete_Click" OnClientClick = "return childnode();"
To this:
onclick="btn_delete_Click;return childnode();"

Javascript is not called on radiobutton list index change

I have written code for javascript but it is not called any how. I tried to call both form html side and also by assigning attribute from page load event but it is not at all called.
This is the code for my javascript.
function rdbantiplatelet_onClick(thiscontrol, trName) {
alert('hi');
var RB1 = thiscontrol;
var radio = RB1.getElementsByTagName("input");
var trDose = document.getElementById(trName.toString());
// var RB1 = document.getElementById("<%=this.rdbantiplatelet.ClientID%>");
// var radio = RB1.getElementsByTagName("input");
// var tblAntiplatelet = document.getElementById("<%=tblAntiplatelet.ClientID %>");
for (var i = 0; i < radio.length; i++){
if (radio[i].checked){
trDose.style.display = "";
return true;
}
else{
trDose.style.display = "none";
return true;
}
}
return false;
}
This is the code to call javascript written in page_load event..
rdbantiplatelet.Attributes.Add("OnClick", "return rdbantiplatelet_onClick(this,'" + trDose.ClientID.ToString() + "');");

Try an alert() first to make sure your onclick is firing, then try your rdbantiplatelet_onClick() function:
rdbantiplatelet.Attributes.Add("OnClick", "alert('I am working');");

First of all for your reference here is a list of standard html events
http://www.w3schools.com/tags/ref_eventattributes.asp
try adding something like this to the html radiobutton element
onchange="alert('on change fired');"
and
onclick="alert(' on click fired');
so you can make sure you are picking up the right event.
Once you have the right event then replace the alert call to your method
which would be something like this
onchange="rdbantiplatelet_onClick(this, this.parent.id)"
...you might have to change the 'this.parent.id'
Make sure you are running through a good web browser for development FireFox with the firebug plug-in is great for this stuff.

You are add click event to html table that holds radiobuttons. Use script below:
foreach (ListItem item in rdbantiplatelet.Items)
{
item.Attributes.Add("onclick", "return foobar(this);");
}

Get the return confirm popbox value in asp .net C#

How can i get the value that was pressed in the confirm box?
<script type = "text/javascript" language = "javascript">
function confirm_proceed()
{
if (confirm("Are you sure you want to proceed?")==true)
return true;
else
return false;
}
</script>
C#
Button2.Attributes.Add("onclick", "return confirm_proceed();");

Try this, if this is the only button that has this behavior
Button2.Attributes.Add("onclick", "return confirm('Are you sure you want to proceed?')");
it's inline and looks straightforward but if you have multiple controls that behave this way then your original approach would be easy to maintain.
And your original function could be shrunken to
<script type = "text/javascript" language = "javascript">
function confirm_proceed()
{
return confirm("Are you sure you want to proceed?");
}
</script>

You can store the value of confirm_proceed() in an asp:HiddenField
You can modify your script as follows:
<script type = "text/javascript" language = "javascript">
function confirm_proceed()
{
var hiddenField = document.getElementById('hiddenFieldId');
if (confirm("Are you sure you want to proceed?")==true)
{
hiddenField.value = 'true';
return true;
}
else
{
hiddenField.value = 'false';
return false;
}
}
</script>
You can now access first the hidden field's value in your Button2_Click event.

I just face similar problem in a real production project and I solved it by the following:
<asp:Button ID="btn1" runat="server" OnClick="Button1_Click" onClientClick="return confirm('Are you sure you want to proceed?')"/>
so the OnClientClick Client event is raised befoere the onClick which is a server event , so if the user clicks OK then the Client event returns True from the confirm Dialog and therefore the Code Behind this button is executed , on the other hand if the user clicks (Cancel or No) then it would return false and therefore the code behind wont get exected (Server Event is Cancelled)
hope it would help you as I really applied it to my project and worked without any issues.