I have a question to understand the concept of ASP.NET with each client browser.
I am trying to update the XML on server when a user hits a particular page on my website.
This page is dynamic, but too large so I want it to load using an XML file also I have several drop downs on the page when user changes the value in drop down, I need to refresh the data based upon the selection, additionally my drop down is a custom designed here I do not get and selectedIndex change event.
So I'm using JQuery to get the changed value in my drop down and planning to read XML from jQuery and display the data.
But since the XML is updated on hit of the page on server, I want know, if multiple users hit the same page, will the data displayed as per each users selection or it will mix the data and show the last hits record.
If I'm not mistaken about your question, you basically ask the following:
You have an XML file, which is updated, on some event from user. The page, which is displayed to the user is based on this XML file. What info will users see, when multiple users are working with the application?
This greatly depends on how you are using that file. In general, if you try to write that file to disk each time, users will see the last update. Basically update from the last user.
However, you can synchronize access to this file, write the file on per-user basis and you will see a per-user output:
<data>
<selectedData user="user name">123</selectedData>
<!-- and so on -->
</data>
UPDATE:
For anonymous users this would not work well. However, if you need to store the selection only for the current user, you can use SessionState and not an XML file.
I would like to introduce a new way that it helped me to answer my above question.
What i did here is
on Page load we added all the information related to each section in different hidden fields.
suppose i have three section with my custom drop down!
What exactly we implemented is that on click on my custom drop-down, we separated the values from the hidden field with the separator we entered and displayed the data accordingly, small part of logic but it helped in displaying the data without post back.
and Jquery helps a lot to me for just changing the inner html of my block.
Related
I have a Layout page which sets up the list of Projects in the application using Telerik's ComboBox as shown. The combobox allows user to select a project he/she wants to work on.
Once a selection is made, I want all subsequent actions in the application should correspond to the selected Project. I can preserve the Project information in a Session but then if user chooses to open this in a new tab and in 2nd tab users switches to a different Project and comes back to the first tab and refreshes the page then the session information (Project) would have changed which will create issues in my application.
So, what is the best way for me to persist Project information of the Layout.cshtml controls so that I can use it in my application such that every page that is rendered uses the currently/correctly selected values.
Tempdata / QueryStrings came to my mind but i don't know whether they will be reasonable solution to my problem. If yes, then how should I use them generically (specially querystrings) without complicating my solution?
localStroage and sessionStorage also seems like relevant solutions but then how do I use them in scenario where user opens a new tab from existing page? How will the Project # will persist on the newly opened page/window/tab?
something like this is achievable, if you make sure the url changes when a selection is made.
So let's say you select project C-1379 in your dropdown box, at that point your url could become http://localhost:58692/pid=C-1379.
from now onwards, your page can load the desired data, retrieving its required information from the query string. Do not use session or localstorage or anything like that as it won't work.
This way, you can still load your list of projects in your layout page, and you can select one based on the query string value and then load some default values via api calls to the back end.
If all your work from now on is done based on api calls, for example, you have some properties that you change and then you issue a POST to update said details then this is very easily done as well.
telerik controls usually have some events associated with them. the one you are using should have an onChange or something like that. This where where you would update the query string with the value of the project selected and then you can proceed to do what you need
I can preserve the Project information in a Session but then if user
chooses to open this in a new tab and in 2nd tab users switches to a
different Project and comes back to the first tab and refreshes the
page then the session information (Project) would have changed which
will create issues in my application.
I would have thought this is the desired behavior... take stackoverflow.com as an example, if I change my username in one browser-tab, I would expect my username to be updated in other browser-tabs as well... and that's what happens if I refresh my other tab.
There is no built in solution for maintaining user info in different browser tabs separately... the only way to achieve this, is by sending project name back and forth in the URL... but then you would loose this info if user changes the URL... In my opinion, this is an ad hoc solution and does not worth the effort of development, because it's a very uncommon scenario.
Getting to your options:
Storing user info is a very typical use case for session variable.
TempData is stored in Session by default. Though you can write
your own custom TempDataProvider and store it somewhere else (e.g.
database, cookie, etc). See Brok Allen's Cookie TempDataProvider
as an example. One advantage of using Cookie is that you send your
session variable back and forth with the request so you don't need to
worry about Sticky Sessions.
You can of course use a permanent storage, such as DB/Disk.
If the project name is not a sensitive info then I don't see any issue in passing it in Query String.
I have a web page written in ASP.net where it finds a list of employees, displays them in a listview and allow the user to change different statuses for each employee.
On each row I have employee information like name, date of birth, address and then 4 status fields that are displayed as checkboxes and a comment field where the user can type a comment explaining why they changed a certain status.
Currently in Listview, there is an edit, delete button when they click edit, the checkboxes and text field are displayed the user updates them and click save.
asp.net will do a postback to save the changes for this row and then fetches the data again to refresh the list.
The problem I am having is the list is very large (more than 3000 names), so I am using pagination to show 50 to 100 names on each page. This is still a big performance problem because after every line update a query needs to run to fetch those names again, and with ASP.NET the server is generating the html and passing everything to the browser.
The customer wants the page to be mobile friendly too, so I am thinking to redo the page using Angular on front end with web-api or mvc.net on back end that returns JSON.
My question is there an easy way to do this and allow the user to change the status for multiple employees on the same page at once and then click one submit to update all the changes? if I do it this way, there will be less queries to run and it will be faster for the user because they don't have to wait after every line update.
Any examples will be greatly appreciated, unless there is a different way to implement this, in this case please let me know.
I have a thought that may work.
On load render names and use pagination.
Then use ajax to send the post to server and change data in database.
When editing has returned successful then only change the values that have been edited using javascript for the user to view.
I have 2 views in my SPA built up using durandal. I have a form (consider basic employee information form) in the first view. Also, I am having a button in the view called "upload" which routes to a different view to upload some documents. Once user finishes uploading, it redirects back to my first view and when it does, the first view reloads (renders) again loosing all my previously entered values. Same is the case when I press browser back button on my second view (the upload page).
Any solution on how I can persist data in this case ?
Thanks.
Posting code would make it a bit easier but I would think you'd need to maybe store what's entered in LocalStorage or something and then retrieve it later?
AmplifyJS can make this easier.
I'm trying to describe it in as few steps as possible:
I have Page1.aspx with lot of controls, and Preview and Save button among those. I also have Page2.aspx that is the redirection target of a Preview Button click.
Since I need all the controls selections from Page1 to draw a preview on Page2 the redirection is done with setting Preview's PostBackUrl.
I also must have preview shown on a new tab or window so I used onClientClick="aspnetForm.target='_blank'" for Preview button definition.
Save button-click callback, after storing data to a database does redirection to some Page0.aspx (initial list of reports - the subject of the code)
Preview button works fine - a preview renders in a new tab, but when I go to the old tab and click on Save, I see from debugger, that firstly Page2.aspx(?) and secondly Page1.aspx are loaded. Then all the data is stored in the db, but though Page0 redirection is executed Page1.aspx stays loaded in the browser.
I have no idea what processes are behind this. Could one who knows give me an insight? Or if you consider my approach impossible to implement give some idea how to do the same?
If it's of importance, everything on the Page1 is located in an update panel.
Thank you very much for replying
In ASP.NET there are basically zero (0) circumstances in which you will ever send form data from one page to another. Although what exactly you are trying to accomplish is vague, you can consider some of the following:
Isolate unique operations/systems to a single page. If you have something like a User Profile, don't have three different aspx pages; just use a single page for the user or admin to manage that data / functions. Postback events are your friend.
Understand the difference between ViewState and traditional form data. I'm guessing that if you're trying to post form data from one page to another, you probably don't understand the point of ViewState. Using a single page to maintain temporary data that the user is currently working with is a great use for ViewState. If you want the data to appear on another page then you need to consider the data from the previous page as final and thus should be saved to a database or some other medium.
These are just some general guidelines because there is no exact answer to your problem without saying something generic like "You're doing it wrong." I would recommend starting by never again trying to post form data from one aspx page to another.
The problem that I am having is as follows:
I currently have a custom class that generates buttons and places them on a placeholder on a master page.
The events for these buttons put specific values into session that differs values for a database query. In essence, the buttons serve as filters for charts.
After creating all the buttons, I realized that session values will stay constant from page to page, so everytime a user enters a different page while another is open, the filters selected on the open page will remain constant for the new page that is opened.
At first, I wanted to use viewstate rather than session, but then realized that a master page and a content page do not share the same viewstate.
At the current time, I am thinking of using a prefix for the sesson key that will identify what page the filters actually exist for. However, I am not wanting to overload session with numerous values if the user wishes to have many pages open at the same time.
Any solutions that would entail a way to share viewstate (or some other way to store values) between app_code, the master, and the content page?
Use HttpContext.Current.Items, it is a key-value pair collection with a lifetime of a single Http Request.
Have you considered Context.Items?
How many filters are we talking here? Store the filter values in the URL. Have you seen some of the URLs that google or an ecommerce site uses? They are quite long. Here is how I do it:
I store the filter values in the query like, www.chart.com?filter1=val1&filter2=val2 etc.
I user JQuery's query plugin to manipulate the query on the client side, and then request the chart from the server again, using the new query.
This way, I'm not junking up session, cookies, or anything like that, and if the user wants to store a bookmark to a particular chart or email it to a friend, they can and the filters are preserved.
I'm starting to think the answer shown in the following question will work:
ViewState object lost in Master Page Load
Exposing the desired variables via a property.
If the data isn't too long, cookies are a typical solution.
Another option is to use Silverlight isolated storage. The Silverlight control itself could be invisible (no UI).