I'm looking to make validation for a page in which one or more fields have a value in them. I have an advanced search form in asp.net and I'm trying to pop up an error and not post back if all the fields are empty. I've looked into required fields validators but I'm not sure how to make them work together in a AND type fashion instead of the OR fashion that a validation group of required field validators would imply. I hope this makes sense. Thanks for the help.
i had to do something similar years ago and i was using 1.1 then.
what we ended up doing was creating required field validators but disabling them.
then onload we would loop through the validator dictionary, enable them and check if they passed. if any of them passed we broke off the loop and we continued execution, otherwise, if all of them failed then we displayed a warning. Unfortunately, this would require a postback.
If you want to accomplish this on the client-side then you could write a simple javascript function to take care of it before postback.
for every control, place an onBlur event. javascript will check if there is a value in the field and maintain a flag. then before submission you would check the flag and either allow submission or show warning.
You could just write the javascript validation function yourself to handle this case and attach it to your search button.
Related
I'm generally an ASP.NET MVC guy, so the "standard" ASP.NET stuff is a little difficult for me to wrap my brain around. I've tried looking for the answer, but the keywords I'm using seem to be too generic... I get a lot of close answers, but not what I'm actually looking for.
I have a grid that is populated from a data set. One of the fields is a dropdown with 4 possible statuses. When the user selects a status, an event is fired in the codebehind to make the change in the db immediately.
There is a particular status that I need to confirm, because once it's selected, it's irreversible. Figuring out how to have the back end pop up a confirmation box was annoying, but I think I have that part done now.
The problem is, if the user confirms that the status they selected for the dropdown was intended, I need to disable any further changes to that dropdown, either by disabling the control or by removing the row altogether. With this requirement, I imagine I need to pass a reference to the specific control that fired the event back to the script, so that it can pass it through the postback, where I would need to consume it.
I have no idea how to pass a reference to the control (what can be used as a reference?) and I have no idea how to use that reference in the postback.
Any help would be greatly appreciated.
;p i was waiting for you to find my post on the issue lol.
but to put it simply, you postback to the page, all members are still available to you if you instantiated something in codebehind. if not, then use FindControl to pull them from DOM. here's the passing values stuff.
as long as you don't kill the lifecycle, you're fine: Passing dropdownlist selected value to another page's dropdown list
and here is the linkspam (full docs): How do I keep TCP/IP socket open in IIS?
probably the articles on session-state and page lifecycle will be of most use.
To prompt the user for confirm add this attribute to dropdownlist.
onchange="return confirm('Confirmation Message');"
I have a website in ASP.NET (WebForms, NOT MVC) which has a survey form divided in several slides. Each slide has a next button that, obviously does a transition (client-side, not post back or remote request) to the next slide.
In each slide I have several ASP.NET controls with their related validators. I want this validators to be triggered when I click the next button (or maybe when each input loses focus?).
I remembered ASP.NET doing client side validation on lost focus, but maybe I'm wrong... (I quit doing ASP.NET development about 3 years now, so I can't remember)
Thanks
UPDATE:
It would be better to make ASP.NET trigger each validator when the associated control lost focus. I remember ASP.NET doing this (or am I dreaming? =P)
First you need to make sure all of your validators have target controls specified using the "TargetControlID" Attribute on the validators.
Then you can set up a validation group per page and specify the group name in your next button and on the controls themselves.
If you are using regular expression validators you can choose them from this website
To Validate Client Side
If you are using custom validators you can create a client function and specify it on the custom validator using the ClientValidationFunction attribute and by setting EnableclientScript = "true" on the custom validator.
Just be sure your client function has sender and args parameters.
It looks like there's a supplied JavaScript function called Page_ClientValidate which should be callable to check the validation manually from JavaScript. I haven't used it, though, so YMMV.
put all your client-side validators into the same validationgroup and with your 'next' button add the same validation group. When you click the button it will automatically trigger all the validators before it does the post-back.
as to manually triggering the validation...
you might also be able to use ValidatorOnSubmit(). I remember doing this in another project but i'm having a hard time finding the code.
It seems that enabling 'SetFocusOnError' on each validator triggers the validation whenever I try to leave the field.
In short decorate your model, now Data Annotations are supported from Asp.Net 4.5
Check my Answer here..Client side webform validations
Hi
I need to validate two fields in an Asp.net form, where the requirements is like any one of them is required. For example, there is Page title and sub-heading input boxes, so any one of them is required. Can I do it using the validation controls Asp.Net provides?
Any kind of help is greatly appreciated. Thanks in advance.
You can use a CustomValidator control (MSDN) in ASP.NET for special situations that are not supported by any one of the other standard validators. It was created for this reason.
Microsoft describes how to create a custom validation function here.
Here's another tutorial on implementing it.
Or if you google for keywords like "creating a custom validator in asp.net" you can pick and choose from various solutions for your own project.
For your case, as an alternative to using a CustomValidator, you could explicitly change whether your required field validators are enabled by using the ValidatorEnable() JavaScript function.
// disable validation control
ValidatorEnable(RequiredFieldValidator1, false);
You can then write custom logic in JavaScript to determine the case in which each validation control is either enabled or disabled, and tie it to one of the (client-side) events of the text boxes (onblur, onchange, onkeyup, etc).
Then, on the server side you can write similar logic to do the same thing by setting the "Enabled" property and put this logic in your button click event before you check the IsValid state.
If all you are doing is conditionally determining when something is required, changing the enabled state is your best bet. Exactly what can be done is documented in ASP.NET Validation In Depth.
I have a custom class (ServerSideValidator.vb) that validates user input on server side (it doesn't use any of the .NET built in validators, therefore Page.Validate() is not an option for me). I am calling the Validate() method on page.IsPostback event and the class performs without any problem
My issue is, when validation fails (returns false), I want to stop the postback event handler from firing, but load the page along with all the controls and user-input values in them. If I do, Response.End(), the page comes up blank. I can programmatically instruct the page to go to the previous page (original form before postback), but it loses all user-inputs.
I thought of creating a global boolean variable in the page code behind file and check the value before performing any postback method, but this approach takes away from my plan to provide all functionalities inside the class itself. The page object is being referenced to ServerSideValidator.
Seems like all the postback related properties/variables I come across inside Page class are 'Readonly' and I can't assign value(s) to control/prevent postback event from firing.
Any idiea on how I can accomplish this? Please let me know if you need further details
It's probably easier to post back to the same page every time and do your validation there, specifically on the page load event. If the validation fails, you're already on the correct page and don't have to go to a previous page. If the validation succeeds, then you can redirect to another page if you wish, in which case you probably don't need any data.
Edit: This isn't exactly what you asked for, but I have a feeling it will do what you want while fitting into the existing ASP.NET validation design. See http://www.dotnetcurry.com/ShowArticle.aspx?ID=197 and https://web.archive.org/web/20211020145934/https://www.4guysfromrolla.com/articles/073102-1.aspx
Basically, you create a custom class just like you have now, but inherit from BaseValidator. To follow your design, you can create an enum called ValidationType which has Alphabetic, Alphanumeric, etc. In your custom class, create a property called ValidationType that uses the ValidationType enum. Of course you have to add all the validation logic. Then in your aspx page, you can add your custom validator to the page and set ValidationType="Alphabetic", etc. with full IntelliSense support.
Since you use BaseValidator, all the regular validation techniques will work including Page.Validate(), Page.IsValid, etc. You can even create client-side validation JavaScript if you wish.
Having said this, someone has probably already done most of this for you.
ASP.NET has a number of nice features regarding making data input pages:
Adding input controls is easy (<asp:...).
The system automatically generates member variable for the controls.
Post-backs automatically populate the members variable with the returned values.
and some not so nice bits
post-backs seem to be tied to JavaScript for even the simplest of cases. For instance, with statically defined pages, using only basic controls, that are known at compile time.
My questions:
Is is possible to get the first list without the second?
What features does that JavaScript give the user?
What does that JavaScript actually do?
What is the technical reasons that it's used even in trivial cases?
As it happens my assumption were in error: See here
It really depends on the types of controls you are trying to use here -- the only ones that implement javascript are those that can't natively cause a postback (ie, an input/submit button are the only two that can). If you are using a LinkButton, ImageButton, or anything that you set "AutoPostBack = true" on will turn javascript on in order to cause a postback.
Other controls can also potentially use javascript if they are more advanced such as the Calendar. The technical reason for using javascript here is to provide automated postback when the controls require more advanced server interaction -- think about it, a link is meant to only ever be a link and if we're trying to make it operate as a button we have to force it to do just that through javascript interaction.
So that being said, yes you can definitely use ASP.NET without it having javascript you just have to avoid the controls that implement it by including functionality you couldn't possibly have without it. You can just as easily add HTML controls and add the runat="server" attribute and gain member variables to the control from code-behind.
Here's what came to my mind:
What features does that JavaScript give the user?
Client side validation.
What does that JavaScript actually do?
For exmaple, it ensures that the correct (server-side) event handlers are called, by setting the __EVENTTARGET hidden field.
Is is possible to get the first list without the second?
You can use normal HTML controls instead of the ASP.NET controls. Then on the server-side, you can read the control's values from the Form collection.
I assume you mean the javascript associated with an <asp:Button /> control, right?
In addition to the reasons mentioned by Fooberichu, the javascript can also help with ASP.NETs client side validation framework.
But I think it's primary use is to alert the framework what events it should fire on the postback in the page behind.
So if you had two buttons on the form, SaveButton and DeleteButton, the javascript helps the framework know whether it should execute the SaveButton_Click event or DeleteButton_Click event.
Hope this helps.