• 0

How can I prevent a page from navigating away if a textbox is not filled?


Question

I have

 

<asp:TextBox ID="info" runat="server" CausesValidation="true" ValidateRequestMode="Enabled" />

 

// A textbox called info

 

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"

ControlToValidate="info" ErrorMessage="You must enter something" Display="Dynamic"> </asp:RequiredFieldValidator>

 

//A validator to make sure info is filled.

 

 

 

But, I am still able to navigate away from the page.

What else do I need?

 

 

Do I need to in every other <asp: controls type in some stuff as well? Or just only one more block of code will do it?

 

23 answers to this question

Recommended Posts

  • 0
  • 0

I need a code that prevent me from going to another link (within my site) when the textbox isn't entered.

 

That demos is very basic, just shows the simply error message and not on navigating away from the page.

 

I know how to display error messages, but the 'unable navigating away form the page' baffles me.
 

 

 

The validation control does not care about users navigating onto other pages, but I need to know how to do this.

 

  • 0

Let me clarify what I mean,

 

if textbox is empty, or a button that inputs the value from the textbox has not been clicked, you can not visit any other pages that's linked, that includes a masterpage and trees/menus

 

It need to stay on that page until this information is entered into the box.
 

Do you understand what I mean?
 

  • 0

I guess you would have to have an event handler for clicking the links

can't you put some code in there that checks if the length of the field is not 0

if so then just do nothing, otherwise you move on

  • 0

What event-handler do I need? But Where does it go? Since everything is ALL combined with a masterpage, so it should go inside the Master page or just that page where you are required to enter a text?
 

Maybe it should go under Master page, I dunno. I also have ASP menus/trees, that can't function either unless this textbox MUST enter a value.

 

  • 0
  On 15/11/2014 at 21:29, SuperJediMedia said:

Let me clarify what I mean,

 

if textbox is empty, or a button that inputs the value from the textbox has not been clicked, you can not visit any other pages that's linked, that includes a masterpage and trees/menus

 

It need to stay on that page until this information is entered into the box.

 

Do you understand what I mean?

 

 

If you want to tell the users to fill the form and lock them on that page until the form is filled out, then that would be a problem...

 

because it doesn't work that way because the user can close the browser down and pull it up and visit somewhere else.

  • 0
  Quote

because it doesn't work that way because the user can close the browser down and pull it up and visit somewhere else.

 

I think I know what you are saying, but it's not what I mean at all

I am trying to learn how to program/design a website, understanding how THIS aspect work, everything within this site is what I need to worry about.  What you are talking about (The web browsing basics) isn't what I am talking about.

 

  • 0

Correct me if I am wrong, but I believe I should put this event-handler inside the Master Page, not just this one page. Since if I goto  any of the other links, it can't access them unless I input something from this textbox into memory, first.

 

 

Like inside Master Page's

 

protected void Page_Load(object sender, EventArgs e)

 

{

 

I put in something to check the value of text.

}
 

Any tutorials on this would be great. I can't find them though :(

  • 0

Well I said in the Master Page Page_Load that

 

 if  (this text value == null)

 

{

 

Response.Redirect(" (to this page to input values into the text box)");

 

}

 

But it doesn't do that, it acts like this value isn't null, I am pretty sure that it is null though.

  • 0

Please, I really got to know how to do this. If any of you can even just share with me an online Tutorial that talks about how to prevent a page from navigating away, I would be greatly appreciated!!!

  • 0

Why not write some actual js instead of using asp...

Anyway theres a problem you will run into, you cannot and never will be able to prevent a user from navigating away. Most you can do is showing an alert popup.

What you can do is preventing a user from clicking a link on your page and navigating to the link url.

Following code can be used for that:

$("a").click(function(e) {

if($("#inputelement to check").val() == "") {

e.preventDefault();

}

};

Above code uses jquery but can also be written with pure js.

If you want to learn some proper web development I'd suggest to not depend on asp only but also learn js...

To make writing js simpler you can try learning jquery which is simple js library and easier to learn then pure js, especially when working with the dom.

Keep in mind that this is bypassable for users with disabling js.

What you also can do is the following:

Masterpage has a inputfield and on submit it check the input value, if it's not empty it will save a cookie in the user it's browser.

On all the other pages just check for the cookie and when it does not exist redirect to the masterpage.

This can be made even secure by generating a unique cookie that's stored in a database for each user.

You can also do above with a session variable in asp that's set to true when a value has been submitted. Though this variable is reset when the browser is closed.

The method you choose depends on the website it's use case.

  • 0

Reiterating what others have been saying...

 

You must learn js in order to dynamically control what the user can do on your page like you describe.

 

You have at least the following two ways of implementing this in the page:

  1. Assign an event handler to every link, button and form on the page, which simply cancels the navigation (by simply returning false if I remember correctly). JQuery will help you write some simple code to select all of the necessary HTML elements from your page and assign such an event handler. You would then have an event handler attached to this text box that then removes these event handlers to allow them to work again once your validation condition has been satisfied (textbox is not empty). It may also reapply them if the user deletes the textbox content leaving it empty or otherwise invalid. These event handlers may need to be created and assigned on page load.
  2. Or, if your page structure allows it, while the textbox content is invalid, create a new "overlay" element which, with CSS, covers the entire page, and then with CSS place your text box on top of this. You may need an event handler on this overlay element to stop click events propagating down to things beneath it. This overlay can be added or removed to block or allow respectively user interaction with the rest of the page.

You would also need to add an event handler to block the user leaving the page via the back/forward browser navigation buttons, by closing the tab, by closing their browser, by clicking on a bookmark, by changing the url in the address bar, etc.

 

Understand that protection mechanisms like this are never perfect. A sufficiently knowledgeable/skilled user could remove such blocks with the web developer tools built into the browser for example.

 

You may want to seriously consider whether the design of your application could be improved. Your current requirement of such forced control over the users actions may be a result of a bad design. Why not describe to us in detail the functionality of your application and the problem you're trying to solve by implementing such restrictions. Perhaps we could dissect and discuss your design with you and then maybe come up with a better solution.

  • 0

I must use C# .NET, not JavaScript.

 

As for complexity, +theblazingangel I think you are thinking too complex, but I require nowhere as complex as blocking from going to another website, pressing back button, etc. Only that it can not goto another page linked in my site.

And, I don't even need a popup, just that it can not go to another page unless information has been entered.

 

ALL this should be really really easy to do, but I am just learning.

 

  • 0

I haven't programmed in a long time but this seems like something you really want to handle on the client side

 

Can't you just have a general event handler for the click event?

In that event you can just check if the textbox is empty

If it is you let it go on with the link

if not you just do nothing

  • 0

Just as I said before use asp session variables if you want to do it server side.

 

If you did something else then I'm interested in what exactly you did  :)


  On 16/11/2014 at 07:32, alwaysonacoffebreak said:

Not be an ass or anything but the thing You're doing is the most annoying thing on webpages. It doesn't let You back out.

Hmm he's just using the wrong words to explain what he wants, what he actually wants is just requiring a user to enter a field with something like a username before giving them access to the rest of the site.

  • 0
  On 16/11/2014 at 11:36, Seahorsepip said:

Just as I said before use asp session variables if you want to do it server side.

 

If you did something else then I'm interested in what exactly you did  :)

Hmm he's just using the wrong words to explain what he wants, what he actually wants is just requiring a user to enter a field with something like a username before giving them access to the rest of the site.

 

Oh okay. Then my bad. I just found it weird that he wanted to (by the title) to lock people down before they fill in a box. :D

  • 0
  On 16/11/2014 at 03:38, SuperJediMedia said:

I must use C# .NET, not JavaScript.

 

As for complexity, +theblazingangel I think you are thinking too complex, but I require nowhere as complex as blocking from going to another website, pressing back button, etc. Only that it can not goto another page linked in my site.

And, I don't even need a popup, just that it can not go to another page unless information has been entered.

 

ALL this should be really really easy to do, but I am just learning.

 

 

Why can you not use JavaScript? Is this arbitrary restriction imposed upon you because this is a homework exercise and your tutor has said so, or because you're "trying to learn how to program/design a website" and you don't yet understand how JavaScript fits in and how it may help you achieve what you're after, or because you know enough to recognise that the solution to your problem must be implemented in server side code but you haven't explained things well enough, or because JavaScript is/may-be disabled on the client browser which would cause problems??? Without any disrespect, you are just learning web-dev, whereas myself and others here have quite a lot of experience, so if we're suggesting that you use JavaScript for something and you tell us you can't, please provide an explanation as to why!

 

You've stated several times that you are trying to prevent the user from navigating to other pages on your site, but yet nowhere have you actually been clear enough about exactly what you're trying to achieve. Are you trying to just keep the user within this particular page you've been trying to build, with them having navigated to it somehow, until they have filled in this mysterious textbox (i.e. for some reason prevent them moving away to other pages, but they can load other pages say in a different tab without restriction), or are you trying to block access to all pages on the site until this mysterious textbox has been filled in (textbox displayed by all pages instead of proper content until filled in, or perhaps all pages redirect to the textbox page until it's filled in).

 

What you've described to us in every post so far is entirely ambiguous. It came across to me that you were trying to achieve the former of the two possibilities above, but you may well be trying to achieve the latter.

 

What I am trying to steer you towards is getting you to actually describe what this mysterious textbox is for, what data does it capture, and from there we could work towards figuring out which of these designs I've described above is the one you were trying to build and more importantly what problem exactly you are trying to solve. With a proper understanding of what problem you are trying to solve, we would then be in a position to not only guide you as to how to implement a solution, but also to assess whether your approach would actually work, and perhaps offer up a better one.

This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • Videomass 5.0.26 by Razvan Serea Videomass is not just a common converter, it features file concatenation, time trimmer, ability to create thumbnails, tiled mosaics and animated giffs from movies; it has sophisticated GUIs for video filters, previews for video stabilization, resizing, croping, transposing, color equalization. It features PEAK, RMS and EBU audio normalization with streams indexing capabilities, a volume analyzer, audio preview and many more interesting features… For the people that are familiar with FFmpeg, it has a highly customizable preset manager with the possibility to easily make your own presets through the GUI and adapt this to your specific needs or create new presets using the FFmpeg command line. For less experienced people there are also ready-to-use presets. It offers out-of-the-box all possible file formats like MP4, M4V, M4A, MKV, AVI, OGV, WEBM, MP3, AC-3, WAV, OPUS, FLAC, OGG and encoders like MPEG-4, H.264/AVC, H.265/HEVC, VP8, VP9, LIBAOM-AVI, VORBIS, PCM, LAME, ALAC, etc. Also you can copy audio or video streams (lossless mode) without re-encoding, or extract audio from videos and much more! Main features No ads Multi-Platform, work on Linux, MacOs, Windows, FreeBsd. Batch processing. Queue management (only available for Presets Manager and A/V Conversions). Advanced log file management. Multi-panels, switch between panels using keyboard shortcuts. Audio/video processing using advanced tools and sophisticated filters interfaces. While downloading audio or video you can now do other transcoding tasks. Multi languages support (English, French, Italian, Russian, Dutch, Portuguese-BR, simplified Chinese, Spanish-ES, Spanish-CU, Spanish-MX) Conversions and transcoding Drag and drop to add multiple files simultaneously. Fully customizable presets and profiles. Possibility to create your new presets and profiles from scratch. Has useful presets to start with. Using the Presets Manager, you can set any format and codec supported by your FFmpeg build. Media file info (from FFprobe) and streams analyzer (from volumedetect). Shows the estimated time of arrival during encodings. Concatenate, merge media files losslessly. Create Slideshows. Extract images from video. Ability to switch between different FFmpeg builds. Has useful graphical tools for evaluating the supported features of a specific FFmpeg build. Audio stream mapping using selectable indexes. You can set both audio and video to copy when you just want to convert formats (lossless process). Timeline editor to slice time segments or trim the duration of your media even without re-encoding and therefore without loss of quality. It has GUI video filters such as: Resize Crop Transpose Deinterlace Denoise Stabilize Equalize Audio filters for volume normalization such us: PEAK, RMS and EBU-R128 normalizers. PEAK and RMS volume analysis reporting. Ability to select specified audio streams in videos to apply volume normalization. and much more… Videomass 5.0.26 changelog: Fixed yt-dlp preferences tab issue #372 Enabled import of the external «yt_dlp» package also on the standalone executable built by Pyinstaller. Improved handling of the yt-dlp executable (yt-dlp.exe on Windows) which now provides some automation and useful information for the users. Added «Whale» browser to the supported browser list for cookie automations. Update it_IT i18n, thanks to @bovirus Update zh_CN i18n, thanks to @userwljs Removed API functionality for download operations. Now only the yt-dlp executable is used for download operations. The API is still needed and will only be used for statistics extraction and format code listing. Fixed #374 Added «FLAC resampler» new preset. Notes: FFmpeg is not included in this archive. Before launching the application, ensure you have a compatible version of FFmpeg for your system architecture (requires ffmpeg.exe, ffprobe.exe, and ffplay.exe, version 5.1 or newer). For more details and downloads, visit: Gyan's FFmpeg builds page BtbN's FFmpeg GitHub releases page Antivirus False Positive Detection Some antivirus programs may mistakenly flag Videomass.exe as malicious. These are false positives. To resolve this, submit the Videomass.exe file to your antivirus vendor for further analysis and request a false positive review. Download: Videomass 5.0.26 | 18.4 MB (Open Source) Links: Videomass Home Page | Screenshots | Other OSes Get alerted to all of our Software updates on Twitter at @NeowinSoftware
    • Who could have thought that Microsoft's (not an ad business) browser is better at blocking ads than Google's (the ad business) browser.
    • So, Microsoft Edge should be behind Firefox and Chrome, because most average users have not heard about it and don't know it's exist.
    • adjusting cleartype did very little, almost nothing.   I will continue to tell people NOT to upgrade to 11 because of this issue.   If I can't customize the computer I OWN, then it's no longer MY COMPUTER!   Screw MS for this omission!
  • Recent Achievements

    • Week One Done
      abortretryfail earned a badge
      Week One Done
    • First Post
      Mr bot earned a badge
      First Post
    • First Post
      Bkl211 earned a badge
      First Post
    • One Year In
      Mido gaber earned a badge
      One Year In
    • One Year In
      Vladimir Migunov earned a badge
      One Year In
  • Popular Contributors

    1. 1
      +primortal
      488
    2. 2
      +FloatingFatMan
      259
    3. 3
      snowy owl
      244
    4. 4
      ATLien_0
      222
    5. 5
      +Edouard
      191
  • Tell a friend

    Love Neowin? Tell a friend!