I'm having trouble understanding page validation - asp.net

Okay, so I have my asp.net page with all of my comparison and requiredfield validators. This leaves me with two concerns.
What additional validation do I need? Do I need anything in the code behind? I want them to be unable to hit the 'save' button until their textbox information is complete, and it seems to be doing this with just the validator controls, but I'm unsure if there are other steps I need to take.
If I have a requiredfield validator and I want to turn it off under special circumstances, where in the codebehind would I set it to true? Can I do it on the 'save' button click, before it prevents the button from functioning?

1.
You need as many validations as necessary, you can create many different validators.
You need server-side validation in the code behind. If a postback occurred then the form passed the validation, but there are some validation features which are unusable at client-side. For instance you register to a homepage and you have a form where the username is required and there is a regular expression validator too. These validators will run at client-side. But if the username has to be unique and you can only check that using a database then obviously this can't be checked at the client-side, therefore, the client-side will evaluate the page to be valid, a postback will occur and it's the job of the server-side to check whether the username is unique.
Note that you can create custom validators if you need to do anything exotic.
2.
Depending on your needs you can set the Enabled property of your validators whenever you need to do that. Read more about that here.

As per my knowledge,
We should include a check for "Page.IsValid" on the server side (code behind) whenever we are using the ASP.NET Validators. This would ensure a check at the server side even if the javascript is being disabled on the browser.
No, you can't do that on the save button click as the button click would not be hit until the validation passes.
Hope this Helps!!

1 if you want add validation server
protected void Button1_Click(object sender, EventArgs e) {
//Proceed only if the validation is successfull
if (!Page.IsValid) {
return;}
}
2 You can set CausesValidation="false" to button

The #1 question with Page.IsValid is ok.
The requiredfieldvalidator is a javascript validator, so you can't disable it from codebehind once it was enabled (unless it satisfies the condition and you can go through). But it's possible to disable it via javascript, check this code:
ValidatorEnable(workPhoneValidator, false);
Link: Dynamically enable or disable RequiredFieldValidator based on value of DropDownList

Related

Can you do a Form submission with Javascript disable

If a user has disabled Javascript in their client browser and they try to use a Form on the Web Page, this causes a Postback. My understanding is that the Form would create a Javascript function __doPostBack to handle the Form submission, but with Javascript disabled a normal Postback occurs. When checking what as been posted back to the server, the Form is empty. Can a Form work with Javascript disabled?
A form ABSOLUTELY works without Javascript.
Just put your form consumption code in the button click event.
something like this perhaps
void btnSubmit_Click(Object sender,
EventArgs e)
{
// When the button is clicked,
// send the values of the input fields to the database.
}
The form will be submitted without javascript.
Any client-side validation will not run, so you may have invalid data. This is why you always, always perform server-side validation of your forms.
Now, you state that your form is empty. If you depend on javascript, jquery, or some other client-side programming to set values in your fields, then you may see empty values. I'm not sure where you're checking, but if you take a look at the request object in your page_load, you should see your data there.

Validation of control contained in page does not invalidate the whole page

I have a RegularExpressionValidator for a TextBox in a control, which itself is part of another control. When I click the button to submit the form, it seems that it should not do so unless all child controls are properly validated. However, what ends up happening is that I see the validation error message pop up for each control that failed to validate before the page posts back anyway and fails when it can't parse the malformed input.
I have tried surrounding the failing code with if (Page.IsValid) {...} to make sure it doesn't run without complete validation, but the property ends up being true by the time I hit the breakpoint.
Shouldn't an entire page be invalid if any child controls are not successfully validated?
Do you have different ValidationGroup controls defined? As long as the validators in the same validation group as the button are all setup correctly, yes it should block. Unless, for some reason, the JS is failing to load for the validators.
HTH.
Set "CausesValidation = true " to your submit button, I guess your problem will be solved.
Have you called Page.Validate() before using Page.IsValid ?

Custom validator only fired on first button click?

I have a custom validator and some other validators on the page. But whenever I click the submit button for first time it only fires the custom validator and when I click the button for second time it's validating rest of the validators. Please let me know if you have any solution.
Thanks
Check your Page_Load to make sure you are not hiding or enabling something after the second call. I had a similar problem before and it confused the heck out of me until I realized I was manipulating a Panel in the Page_Load that contained the validator.
Other than that, you would need to post code (your Page_Load and Click event).
On Client Side when
OnClientClick="return SomeCustomClientCode();"
Is called, asp.net validators e.g required field validators are disabled and it does not gets listed in validators collection and does not validate the field validated by this validator and page post backs if custom validation passes.
To avoid this explicitly enable asp.net validators in Custom validation code or else where so that it gets activated before page postback or in the begiining of custom validation as follows:
ValidatorEnable(document.getElementById('<%=rfvDDLStatus.ClientID%>'), true);
rfvDDLStatus ==> required field validator which was not firing.. ValidatorEnable ==> Client API to enable asp.net validator

Creating custom ASP.NET validator

I have created a custom control and a custom validator (extending BaseValidator). On custom control I have set ValidationProperty("Values"). The problem is that validation doesn't work when postback is sent unless I execute Page.Validate(). And when I call Page.Validate() all validators are executed which is not what I would expect on postback.
How do I create custom validator which would be executed when control value changes and validates just that control?
That is not how validators work. Unless you are using a ValidationGroup setting, all the validators on your page will automatically fire. You do NOT have to explicitly call Page.Validate(). You DO need to wrap your code in a check like this, however:
if(Page.IsValid)
{
//do something here
}
Unlike client-side validators, the server-side validation does NOT prevent the page from posting back and processing events as normal.
To create a control which only validates when the control value changes would require a bit of hackery, since the change event fires after the validators have been executed.
Have you tried using validation groups?

ASP.NET - how to stop unrequired server validation

I have used ValidatorEnable to disable a RequiredFieldValidator in javascript. However on postback the control being validated by the validator is still validated ... even though I disabled the validator on the client.
I understand why this is happening since I've only disabled the client validation ... however is there a nice way to determine that I've disabled the client validation and to then disable the server validation on postback?
You could, when you disable the client validation (presumably with JavasScript?), also set up values in a hidden input that you could query in page load method. This way you can examine the value of the hidden input (via the Request.Form{] array) to disable the validators on the server side prior to the validation event firing.
Another option would be to override the pages Validate() method to disable the validators based on the same rules that hid them on the client side.
It's not clear from your question, what you are disabling. The RequiredFieldValidator has an both an Enabled and an EnableClientScript property.
If you want to disable validation on both client and server you should set Enabled to false.
To disable just client side, set EnableClientScript to false.
Peanut, I just encounted the same issue you are. On the client-side I have javascript that disables required field validators depending on their selections in the UI. However, the server side validation was still firing.
During load, I added a method to disable my validators using the same rules I have on the javascript. In my case, it depended on the user's selection of a radio button:
this.requiredValidator.Enabled = this.myRadioButton.Checked;
This seems to work on the SECOND page load, but not the first. After debugging, I discovered that the wrong radio button is considered to be checked when this line was firing. The View State/Post Data wasn't applied to the control at the point when I was checking it to disable my validator. The reason I placed this during load was to make sure I disabled the validator before it fired.
So, the solution seems to be to have something like the line above AFTER ViewState, but BEFORE validators.
Overloading the Validate() method, as palehorse suggested, worked and allowed me to ensure the server side validators were enabled/disabled based on the current selections of the user.

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