Archives
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Start/Stop Window Service from ASP.NET page
Update: The article has been selected as "Article of the day" on 30th April 2011 at official asp.net (http://www.asp.net) site
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Linq To SQL: Behaviour for table field which is NotNull and having Default value or binding
I found this something interesting while wandering over community which I would like to share. The post is whole about: DBML is not considering the table field's "Default value or Binding" setting which is a NotNull. I mean the field which can not be null but having default value set needs to be set IsDbGenerated = true in DBML file explicitly.
Consider this situation: There is a simple tblEmployee table with below structure: -
Executing server validators first before OnClientClick Javascript confirm/alert
I got to answer a simple question over community forums.
Consider this: Suppose you are developing a webpage with few input controls and a submit button. You have placed some server validator controls like RequiredFieldValidator to validate the inputs entered by the user. Once user fill-in all the details and try to submit the page via button click you want to alert/confirm the submission like "Are you sure to modify above details?". You will consider to use javascript on click of the button.
Everything seems simple and you are almost done. BUT, when you run the page; you will see that Javascript alert/confirm box is executing first before server validators try to validate the input controls! Well, this is expected behaviour. BUT, this is not you want. Then?
The simple answer is: Call Page_ClientValidate() in javascript where you are alerting the submission. Below is the javascript example:
<script type="text/javascript" language="javascript">
function ValidateAllValidationGroups() {
if (Page_ClientValidate()) {
return confirm("Are you sure to modify above details?");
}
}
</script>
Page_ClientValidate() function tests for all server validators and return bool value depends on whether the page meets defined validation criteria or not. In above example, confirm alert will only popup up if Page_ClientValidate() returns true (if all validations satisfy). You can also specify ValidationGroup inside this function as Page_ClientValidate('ValidationGroup1') to only validate a specific group of validation in your page.
function ValidateSpecificValidationGroup() {
if (Page_ClientValidate('ValidationGroup1')) {
return confirm("Are you sure to modify above details?");
}
}
I have attached a sample example with this post here demonstrating both above cases. Hope it helps./. -
Set Confirm alert on browser(tab) close event!!
This is something that might be annoying or irritating for end user. Obviously, It's impossible to prevent end user from closing the/any browser. Just think of this if it becomes possible!!!. That will be a horrible web world where everytime you will be attacked by sites and they will not allow to close your browser until you confirm your shopping cart and do the payment. LOL:) You need to open the task manager and might have to kill the running browser exe processes.
Anyways; Jokes apart, but I have one situation where I need to alert/confirm from the user in any anyway when they try to close the browser or change the url.
Think of this: You are creating a single page intranet asp.net application where your employee can enter/select their TDS/Investment Declarations and you wish to at-least ALERT/CONFIRM them if they are attempting to:
[1] Close the Browser
[2] Close the Browser Tab
[3] Attempt to go some other site by Changing the url
without completing/freezing their declaration.
So, Finally requirement is clear. I need to alert/confirm the user what he is going to do on above bulleted events. I am going to use window.onbeforeunload event to set the javascript confirm alert box to appear.
<script language="JavaScript" type="text/javascript">
window.onbeforeunload = confirmExit;
function confirmExit() {
return "You are about to exit the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?";
}
</script>
See! you are halfway done!. So, every time browser unloads the page, above confirm alert causes to appear on front of user like below:
By saying here "every time browser unloads the page"; I mean to say that whenever page loads or postback happens the browser onbeforeunload event will be executed. So, event a button submit or a link submit which causes page to postback would tend to execute the browser onbeforeunload event to fire!
So, now the hurdle is how can we prevent the alert "Not to show when page is being postback" via any button/link submit? Answer is JQuery :)
Idea is, you just need to set the script reference src to jQuery library and Set the window.onbeforeunload event to null when any input/link causes a page to postback.
Below will be the complete code:
<head runat="server">
<title></title>
<script src="jquery.min.js" type="text/javascript"></script>
<script language="JavaScript" type="text/javascript">
window.onbeforeunload = confirmExit;
function confirmExit() {
return "You are about to exit the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?";
}
$(function() {
$("a").click(function() {
window.onbeforeunload = null;
});
$("input").click(function() {
window.onbeforeunload = null;
});
});
</script>
</head>
<body>
<form id="form1" runat="server">
<div></div>
</form>
</body>
</html>
So, By this post I have tried to set the confirm alert if user try to close the browser/tab or try leave the site by changing the url. I have attached a working example with this post here. I hope someone might find it helpful. -
weblogs.asp.net! I am here now!
Hello all webloggers!!