I have a telerik combobox in mvc3 application and I want to prevent the user writing a value different from the list being loaded from the controller.
A thing that partial helped is to set the textbox input to be readonly but then:
1. The user can filter the list by the textbox.
2. The user can erase his selection.
Another thing that I thought about is: What the user types in the select is the value not the description, so I need it to prevent writing text different from the description while the value remains encapsulated.
Are you still looking to have the user be able to input custom text? If not you can use the DropDownList functionality as seen on this demo page.
If you still want the user to be able to type into the component but somehow have it aware of when they either misspell something, or type one character more than necessary, this can be extremely difficult. You would essentially have to have some clever JavaScript to be triggered with every key press and check the current value against a list. With users being pretty quick with typing, or their browsers being old, this can be very unreliable. Plus, a user can easily disable JavaScript at any time making this functionality obsolete.
I think your best options is to have it as is, where the user can type whatever they want. You can always have validation on the item they have typed and upon blur() or a POST (whatever fits your application) have a message appear to warn them of an invalid entry.
Related
How do I display Price value($) in textbox next to a label when user checks the radio button, select one of item from listBox, and then clicks the button?
Is there way to do it on the form1.cs[Design] using the properties? Or do I need to set them up in code level?
listBox item example
EDIT: Solved this in Code-level.
I don't think you can do it without any code.
Also I'd recommend you to check out this page - just a few simple rules can make your chances to get a good answer on this site much better.
And there is not much of coding needed to solve your problem. Take a look on the Events tab in Property view in form designer. A few event handlers to process user input and some fields inside your class to store the data - I assume it is not some serious business app you're dealing with, so all the code you need for this to work would be like 20 lines tops -)
In my windows application i have a tab control with many tabs and sub tab controls also, each and every tab has many field like text boxes and list boxes.
i thought to validate every field by clicking button called "NEXT" before changing to nexttab and if any field fails with validation a message box should pop-up with error message and focus should remain in that field. can any one help me with ur suggestions...
validation requirements are required field and only numeric and alphanumeric...
Thanks in advance!!!!
A good way is to create a derived controls with input area and validation logic. Then, it is matter of enumerating hierarchy of controls and see if they are valid based on validation rules applied.
Another way, is to "attach" validation logic to controls. How? A mapping mechanism or use the "Tag" property.
But isn't it better to validate control using "Validate" event, when user tries to exit the control? That will not allow user to supply bunch of trash and hope it can be saved.
I have to create a data entry form in asp.net webforms where the user could enter several member details. Each member detail will have about twenty data items such as FirstName, Lastname, DateOfBirth etc. The number of members entered can be anywhere from one to say twenty.
Once all the members entered or during the entry process, they should be able to go to the previous or next entry and make changes. Essentially there should be a Next and Previous buttons which will traverse the pages. At the end when the Save button is clicked all the entered data should be saved.
I have created a UserControl, which has all the textboxes to enter data. I have created five hardcoded panels which display the usercontrol five times. This makes the total members that could entered as five.
I would like to replace this hardcoded model with a dynamically added panel, when the next button is clicked.
Please let me know how this could be achieved. Or if there is a better architecture please let me know. I tried the wizard control, but it was too cumbersome in maintaining the previously entered values and traversing data using Next and Previous buttons.
Thanks
You could add the controls dynamically to the page using:
Page.Controls.Add(new MyControl());
You'll have to find a temporary store for the data entered in the controls though such as Session.
Session["addedControls"] = myControls;
You can track the number of controls they add and then loop though and save all the data to whatever permanent store you're using.
There's an example of this here: http://howto.jamescarnley.com/2008/05/adding-fields-dynamically-in-aspnet.html
Storing the entire control in session does have it's drawbacks such as the overhead involved, you could just store the data which is more efficient but is a tiny bit more effort to implement.
This will also only work if they have cookies enabled.
Alternatively you could have a drop down list for them to select the number of entries they wish to make and display that number of controls by calling Page.Controls.Add the number of required times. Then just save them all in bulk at the end.
You could dynamically add the controls you need to input a new member easily enough in javascript. What you propose sounds like a nightmare to me. I'd put up a page with the controls to add a member and an 'Add Member' button. When the Add Member button is clicked - I would save the member to the database, retrieve a list of members added in this session - and display the names of the members in a list to the right of the 'Add Member' area of the page. If they want to review a member they can click on their name and you can show that member ready to be edited. Or they can add another member until they have finished. What you are trying to do is going to be a nightmare to manage and won't be any easier for the user to use.
Using dynamic controls will be very difficult and not user friendly as it may require refresh the page or using update panel
in your case, I would recommend doing it all from JavaScript using Knockout, This is a full sample Knockout Grid
Make sure after adding or editing the grid, you will serialize the JavaScript objects into string using JSON.Stringify and add this text to a hidden field.
On form submission, just get the hidden field value, use newtonsoft json library to convert the string into an object and fee free to use the object which will be a list of your model (ex: Order).
Compared to dynamic controllers, this is more manageable and user friendly
This seems very simple, but I can find nothing on a web concerning the behaviour I want to add to my custom control.
My custom control is a textBox with a list of choices. When the text entered by the user is not part of the list, a popup will appear with the list allowing the user to select a correct choice.
Sometimes, there may be a default button on the container in wich the custom control has been added. If so, when the enter key has been pressed, if the text is wrong, The popup must been displayed. If there is no default button, on enter, nothing must happen even if the text is wrong.
To be able to create this behaviour, I must be able to detect the presence of a defaultbutton in the container, and it must be done inside the c# code of the cutom control.
I hope the description is clear enough.
Thanks in advance
Have you thought about implementing an MVVM approach and the Command pattern? So long as your view model knows what the choices are, you can bind the default button to a command. So long as the commands CanExecute handler returns false, i.e., an appropriate choice has not been entered/selected, the button will be disabled and won't respond to the user pressing enter.
Since I was unable to know what other controls I had from the custom control I chose to go like this:
I made a recursive function to find the first parent using FrameworkElement.Parent
Having the parent, I could take a look at every controls it contains.
As soon as I saw a button, I had to verify if IsDefault.
For this one, I used the VisualTreeHelper GetChildrenCount(DependencyObject obj_Parent) and GetChild(DependencyObject obj_Parent, int childIndex). Recursivity once again...
It works very well even though it means more code to execute.
This may be a basic question... However I've just been picking a solution without giving much though to it...
Consider a page with a grid of forms: /FormList.aspx
where choosing to edit a form redirects the user to a page like: /FormEdit.aspx?Id=2
I usually am okay with passing the values in the query string, because I check in the code-behind of FormEdit that the Id is valid. Which is the best way to pass the value, though: session or query string? Or other?
While the user is editing the form... I usually save the Id temporarily in session (to avoid getting it from the url again). During the user's form edition, what is the best way to store the value? In the session or in a hidden field ? Or other? (When I want to store a temporary DataTable, I believe I can only use the session, but when it's an integer value...)
Thanks in advance for your suggestions :)
I would suggest not to use Session for something that can easily and quickly be stored and checked in a query string or hidden form field; the information you seem to be talking about here is perfect for the query string.
Note that Session could introduce bugs when someone attempts to edit multiple forms at once in different tabs. When they save one, the Session value taken would be from the last one they loaded up to save... likely not what you will want, and it would likely be difficult to figure this out.
What you should do is persist the formID in the query string/form fields, and just double-check it for sanity when they submit the save; Make sure it's an ID that exists and that they are allowed to edit, for example.
Normally QueryString is a good choice if you are having very small data to trasfer between your pages.
2- Session would be a great when you want to store user specific data.
in you case , best would be the querystring as you are sending very small data (ID ) to the next page.
A few things to consider:
If manipulation of the value is a security risk you need to either save it on the server side, or secure the value client side(Which isn't easy to get correct). Or even better: recalulate them.
Saving in the session can easily create problems if the user has the website open in several tabs at the same time. It can also break the back button.
For example if you safe the ID of the item the user is currently editing in the session, and the user edits two entries at the same time the content of the one he started editing first might be written into the entry he started editing later.
My suggestion is to keep the value in a session variable, but when you run the page_load of FormEdit.aspx for first time, save the value in the ViewState of the page, and clear the session var.
Something like that (in page_load of FormEdit.aspx):
if (!IsPostBack)
{
ViewState["MyVar"] = Session["MyVar"];
Session.Remove("MyVar");
}
The problem with ASP.NET and query strings is that they persist on postbacks. That is, the form action for any page defaults to the url including the query string that was used to load it.
If the ID in question is just used to choose a particular form (and is not related to user data) this is not a big deal, in fact it's probably what you want.
On the other hand, if it identifies a record, you may not want this. Assuming you code things properly, this should not present a security risk, but it can give the user the impression that there is one by exposing the internal ID of a record in the query string. It also just looks unfortunate.
There are ways to work around this, and I think in 3.5 you can programatically change the form action. (It used to be you had to use javascript to do that - even though the form action was exposed it could not be changed).
The best way to deal with this is avoid query strings for any data record identifiers. Use POSTs to load data records instead, e.g. instead of using an asp:HyperLink control, use an asp:LinkButton control.
Of course, since POSTS load the same page they are sourced from, this requires that your forms be on the same page as your list. So, instead of having two separate pages, FormList.aspx and FormEdit.aspx, just put the code on the same page so you can post back directly. Presumably each of your forms is in a UserControl anyway. So your main page just has the job of choosing which usercontrol to show, everything else is delegated to the user controls, and all the parameter-passing can be done through posts inside your main page. This is a better architecture and keeps everything nice and clean.