Im trying working on a web app project and trying to figure out how to display my answer on the second web page.
I have put a a text box on my first webpage and have corrected the coding of my application as I have received the correct answers in the textbox after I have debugged it.
Ideally I want to remove this textbox and want my answers which I managed to display on my textbox displayed on a label in the next webpage. Here is the calculation part of my code;
var cost = ((int)duration.TotalMinutes) * 0.35m;
txtCost.Text = cost.ToString("c");
I'd like to make my answer appear in my second webpage and not have it displayed in the first. I have tried using Session["Cost"] = cost; on the button click event handler of the first webpage double cost = (double)(Session["Cost"]);
lblDisplay.Text = cost.ToString("c");
and this on the second webpage but every time I Debug it and run I always get $0.00 displayed on my label. Can someone help me fix this?
Sharing value between two views in MVC application, try following
// To save into the Cache
System.Web.HttpContext.Current.Cache["CostKey"] = cost;
// To retrieve Cache Value
var cachedValue = System.Web.HttpContext.Current.Cache["CostKey"] as double;
For Session State, have a look at this link
In ASP.NET WebForms application, you can pass data around in various ways:
Cache
See the Learning Curve answer for examples.
However, the object put in the cache is not guaranteed to be found again if the server experiences memory shortage or alike. The ASP.NET manages the cache and evicts objects on its own to maintain memory availability. This is in contrast with ApplicationState and SessionState where the objects are kept until they are removed manually, or the Application ends or Session expires.
Session and Application states
You can put any object in the SessionState object and retrieve it elsewhere in your code. However, you need to cast it appropriately as the SessionState accepts object-s. E.g. if you store a number, when you retrieving it, you must do the casting yourself, just as you already did it.
The reason it doesn't work, is perhaps you're trying to retrieve it from within another user's SessionState. Yes, the SessionState is a per-user structure. If you need to add the value as from one device and use it on another, use ApplicationState:
Application["cost"] = cost;
Redirecting Response
Using this technique, you could force the browser to request another page from the server and specify the full query string, including the variables you need. E.g. :
var destination = Server.UrlEncode("/someOtherPage.aspx?cost=34.65");
Response.Redirect(destination);
As an alternative, you can use Server.Transfer("someOtherPage.aspx") to save the roundtrip. However, in that case, the browser doesn't change the address in the address bar so the user is misled that she browses one page, but in fact, it is the someOtherPage.aspx.
Related
Before I ask this question, I'm not even sure what I'm using is a query string (I'm so clueless on this, what I have is the result of some other confusing StackOverFlow research). It is a parameter I'm passing from my SSRS report viewer to my app via a hyperlink expression. It works and everything is grand except for I'd like to clear it from the url right afterwards.
http://10.155.54.101/Update?CurrencyId=67
And I am getting the parameter with this logic on page load.
if (Request.Params["CurrencyId"] != null)
int CurrencyId = int.parse(Request.Params["CurrencyId"]);
I am successfully capturing that information and populating asp.net controls with it but I want to clear it from the address bar now as it lingers after submitting the update (postback?).
Through another Stack Overflow Answer: Clear QueryString on PostBack , I've attempted to clear the querystring through the following code.
Request.Params.Clear();
But I get a collection is read-only error, which is addressed in the stack overflow question above. So I try to use System.Reflection to change the read only property of the collection with the following code.
PropertyInfo Isreadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
Isreadonly.SetValue(Request.Params, false, null);
Request.Params.Clear();
I don't get the error but nothing is removed, so I might not be referencing the querystring properly because of however the heck Request.Params works.
Can someone nudge me in the right direction with this? I'm so sorry I'm clueless as heck on this.
You can't just change the URL in the address bar of a browser. You could redirect the browser to the URL without the query string, but seeing how you are using the value to populate controls on the page being render that would mean you would need to still need to have that value.
When you say "it lingers after submitting the update", do you mean the user chooses the currency and is redirected to the the page with this query string? If so could you change this action to a POST instead of a GET? Then you could put the currencyId in the body of the POST. If you can't switch it to a POST, then there are a few ideas I listed below.
If you are using session, you could store the currencyId in the user's session. But that would only make sense if you needed to use this value on other requests; as using session is a big decision and if you can keep your website stateless you should.
With that being said, there are two viable options to keep your site stateless. If you need this value on future requests, you can store it in a cookie. If you only need it on this request, you could have the page do post to the URL without the query string but with the value in the POST body.
I am currently trying to allow users to "personalize" their background-image on a website I've created with C#-ASP.net. I imagined as far as that I create a if statement, checking if the currently logged in user matches with the session variable created when logging in, and if it does, it allows him to change his/her background-image. Before I did this, I also thought that the best way of testing if it would work that way is to try to write out the content of the session variable directly onto the page. Thats where the issue come in. All I am getting is the "name" of the session variable and nothing else. How can I get this changed?
The code below is pretty much what I've tried with the session variables this far
<%
// User with the name of "Bob" is logged in with code further up
var login_username = Request["login_username"];
Session["loggedIn"] = login_username;
Response.Write(Session["loggedIn"]);
// Results in it writing out "loggedIn".
// Expected "Bob".
%>
I'm going to be fair, I have no idea if this is enough for anyone to give me a hand and If I am even on the right track, but thats that. If theres a better way of doing this, I'm up for suggestions.
At the time of logging in, store your username into a session variable,
for eg: Session["loggedIn"] = username
Then, read the session value to a label text using
Convert.ToString(Session["loggedIn"]
Alternatively, one can write Response.Write(Session["loggedIn"]); to get the string of the variable.
Is there a way to pass a parameter to a controller without putting it on the URL?
For example,
http://www.winepassionate.com/p/19/wine-chianti-docg-la-moto
has the value 19 on the URL. If you actually change that value to another, the page displays a different record even it the page name remains the same.
So I would like to NOT pass the ID on the URL but still be able to pass that to the Controller.
What's the recommended way to do so?
You can do a post and send it as a form parameter. I do not recommend this. Posts should be for requests that modify data. In this case you're most likely looking just to get that data. The fact that the id is in the URL is a good thing (see the Stack Overflow URLs for reference). If you really don't want the user to be able to modify it (I hope it's not because you think this makes it more secure, because it doesn't), you could do some simple encryption on it to make it more difficult to guess/produce a valid ID.
Using TempData, as some other suggest, is not a robust solution. It won't work for links on a page, just a GET after POST, and then only once since TempData is deleted after the next request.
Well, you have a couple of options:
Is this a form post? If so, then you can simply add a specific key value pair to your form when you submit it and then data will be passed along.
Is the URL unique to that resource? i.e. Does "Wine-chianti-docg-la-moto" exist as a unique representation of the number 19 in a database somewhere? If so, then you can simply do a lookup of that route component in your database to retrieve the value you need (or push that logic all the way down to the database).
Is that a value that is not expected to change a bunch? You can set that value in Session or in a cookie that would be persisted across pages and then pull it from the respective collection.
Are you redirecting to this page from another request on your server? If so, then you can use TempData to store this temporary value. However, I would recommend against this approach, as it is very transient and not good practice imo.
Lastly, you can obscure the value on the URL if you dont want it to be easily user editable. Encrypt it with some algorithm, and then decrypt it on the destination page. The user will be unlikely to be able to alter the ID by typing in a different value in the URL.
If the page is a GET, and you are following the PRG like you should be (Post-Redirect-Get) then you can use TempData["dataName"] = value; in your [HttpPost] controller and then consume it in your [HttpGet] method. It really depends on how the page is being called.
However, there is nothing wrong in letting the user change that number if it is not security related, and is common practice to show non-vital information in the url like that.
You should use TempData in this case. A good read on this can be found on this blog.
TempData allows you to store a value temporarily between requests and is, by default, erased after being accessed.
// TempData samplepublic ActionResult Featured(){ var featuredProduct = new Product { Name = "Assorted Cupcakes", Description = "Delectable vanilla and chocolate cupcakes", CreationDate = DateTime.Today, ExpirationDate = DateTime.Today.AddDays(7), ImageName = "cupcakes.jpg", Price = 5.99M, QtyOnHand = 12 };
I'm looking to create a simple web form, and I would like to "discourage" users from filling a form out multiple times. The metrics of the form are used for statistical analysis, and each time a user fills out and resubmits the form, the result set usually changes, and hence analysis.
While we don't want to BLOCK re-trys (knowing that a re-try was done is also valuable information), we do want to warn users: "Hey, it looks like you filled this out recently. Are you sure you want to fill it out again?"
The caveat here is that we want to minimize the amount of personably identifiable information collected.
Is storing a cookie with the clients IP the best/simpliest way to do this? Or is there a simple method for caching an IP server-side for xx amount of time so we can run a comparison to says "hey, I think this guy tried to access me earlier today. I should present a warning".
Cookie with constant value should be enough, not even IP. If user did not cleared cookies you'd know that the user already filled out the form.
On easy solution I've used before is to put an invisible timestamp in the HTML form the user fills out. If you get submitted the same timestamp twice, you know its a re-submittion.
If you're worried about tampering, you can always mix up/encrypt the timestamp.
This could also just be a random unique identifier, I chose a timestamp in order to know how long a user took filling out a form (roughly).
This is basically like a session cookie, but might be considered more "private" as theres nothing for a client's computer to remember so it can't be used as like some tracking cookies ad sites.
The downside is that this method requires that a client/proxy not cache the form as it "changes" every request.
There are two issues here the user clicking the submit button multiple times, and the user filling in the form at another point in time.
For the second I can see two quite simple solutions would recommend a session cookie, just cookie the users machine and don't let them see the form again, or ask for a piece of information like email address and then check in the DB if its been used before, if so disregard the new form details.
For the multiple form submit you can use this code, which will disable the button onclick.
//
// Disable button with no secondary JavaScript function call.
//
public static void DisableButtonOnClick(Button ButtonControl)
{
DisableButtonOnClick(ButtonControl, string.Empty);
}
// Disable button with a JavaScript function call.
//
public static void DisableButtonOnClick(Button ButtonControl, string ClientFunction)
{
var sb = new StringBuilder(128);
// If the page has ASP.NET validators on it, this code ensures the
// page validates before continuing.
sb.Append("if ( typeof( Page_ClientValidate ) == 'function' ) { ");
sb.Append("if ( ! Page_ClientValidate() ) { return false; } } ");
// Disable this button.
sb.Append("this.disabled = true;");
// If a secondary JavaScript function has been provided, and if it can be found,
// call it. Note the name of the JavaScript function to call should be passed without
// parens.
if (!String.IsNullOrEmpty(ClientFunction))
{
sb.AppendFormat("if ( typeof( {0} ) == 'function' ) {{ {0}() }};", ClientFunction);
}
// GetPostBackEventReference() obtains a reference to a client-side script function
// that causes the server to post back to the page (ie this causes the server-side part
// of the "click" to be performed).
sb.Append(ButtonControl.Page.GetPostBackEventReference(ButtonControl) + ";");
// Add the JavaScript created a code to be executed when the button is clicked.
ButtonControl.Attributes.Add("onclick", sb.ToString());
}
I have stored a string value in a hidden field of a page.
How to access it from a different webpage?
You have two options.
a. Putting that string value in a Session.
string value="value";
Session["myValue"] = value;
b. Transmitting that value in the url.
string value="value";
Response.Redirect("./Mypage.aspx?value="+value);
On the page that contains the hidden value, you could post that form to the other page and get the value from this.Request.Form["hidden-field"].
Is that the sort of answer you are looking for? Maybe more details would help.
Good luck!
If you don't mind using jQuery, and as long as the pages are on the same domain, then you can do it with the .load() method. This method basically does a GET request to the page
Page with hidden field
<div id="hiddenValue">Value</div>
Page you're calling from
$('#newDiv').load('path/to/page.aspx #hiddenValue');
additional notes:
Due to browser security restrictions, most "Ajax" requests are subject to the same origin policy; the request can not successfully retrieve data from a different domain, subdomain, or protocol.
If they are on different domains then your only other options are:
Query Strings
Sessions
references:
http://api.jquery.com/load/
http://www.java2s.com/Code/ASP/Request/GetquerystringfromRequestC.htm
http://msdn.microsoft.com/en-us/library/ms178581.aspx
You can also use cookies to transfer the value across pages. May be you would want to read this piece of article to know more about the state management. Do read it. Will definitely gonna help you. You can decide what you want to use after reading this.
Hope it helps you. http://www.codeproject.com/KB/vista/ASPNet_State_Management.aspx