I have your basic asp.net web form which contains some client-side JavaScript that forces the page to time out and then redirect after 5 minutes. Mainly to protect possibly sensitive information.
At timeout, I want to force a server post back allowing me to save the form values for future edits.
I have played with both ClientScript.GetPostBackClientHyperlink() and ClientScript.GetPostBackEventReference(). Both seem to cause EventValidation issues for me. Yes, I can turn off Event Validation but is there a different or better workaournd?
Ideally, I don’t want to invoke a control (which has to be displayed) but just cause a postback with some type of argument that I can recognize serverside as being the result of a timeout condition.
This may be overkill, but you could setup a javascript timer to fire a web service call. The .NET web service can accept the form data and save it.
No great solutions so I build my own. A pretty simple custom control. Comments welcome.
using System;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace BinaryOcean.Web.Library.WebControls
{
[ToolboxData("<{0}:PostBackTimer runat=\"server\" />"), DefaultProperty("Seconds"), DefaultEvent("Timeout")]
public class PostBackTimer : Control, IPostBackEventHandler
{
public PostBackTimer() { }
public string CommandArgument
{
get { return (string)ViewState["CommandArgument"] ?? string.Empty; }
set { ViewState["CommandArgument"] = value; }
}
public string CommandName
{
get { return (string)ViewState["CommandName"] ?? string.Empty; }
set { ViewState["CommandName"] = value; }
}
public bool Enabled
{
get { return (bool)(ViewState["Enabled"] ?? true); }
set { ViewState["Enabled"] = value; }
}
public int Seconds
{
get { return (int)(ViewState["Seconds"] ?? 0); }
set { ViewState["Seconds"] = value; }
}
[Description("PostBackTimer_OnTimeout")]
public event EventHandler Timeout = delegate { };
[Description("PostBackTimer_OnCommand")]
public event CommandEventHandler Command = delegate { };
public void RaisePostBackEvent(string eventArgument)
{
Timeout(this, EventArgs.Empty);
Command(this, new CommandEventArgs(CommandName, CommandArgument));
}
protected override void OnPreRender(EventArgs e)
{
if (Enabled && Seconds > 0)
{
var postback = Page.ClientScript.GetPostBackEventReference(this, null);
var script = string.Format("setTimeout(\"{0}\",{1});", postback, Seconds * 1000);
Page.ClientScript.RegisterStartupScript(GetType(), "PostBackTimer_" + UniqueID, script, true);
}
base.OnPreRender(e);
}
}
}
Couldn't you use a javascript timer to "click" the submit button? It sounds like using this form would be really annoying though, if it keeps posting back while you're trying to fill it out.
with javascript, call __doPostBack("clientIdOfSubmitButton", null). This will fire off a postback just as if that button (or any other control you want) had triggered it.
Related
Newbie here, I need help with a website I'm creating.
I have a class that does some analysis on some text that is input by the user, the class then finds an appropriate answer and sends it back to the textbox. (in theory)
Problem is I don't know how I can control and access the textbox on the default.aspx page from a class, all I get is "object reference is required non static field".
I made the textbox public in the designer file yet still no joy. :(
I've also read this: How can I access the controls on my ASP.NET page from a class within the solution? , which I think is along the lines of what I'm trying to achieve but I need clarification/step by step on how to achieve this.
Hope someone can point me in the right direction.
Many thanks,
Kal
This is the code I have added to the designer.cs file:
public global::System.Web.UI.WebControls.TextBox TextBox3;
public string MyTextBoxText
{
get
{
return TextBox3.Text;
}
set
{
TextBox3.Text = value;
}
}
This is the class method i have created:
public static cleanseMe(string input)
{
string utterance = input;
string cleansedUtt = Regex.Replace(utterance, #"[!]|[.]|[?]|[,]|[']", "");
WebApplication1._Default.TextBox3.text = cleansedUtt;
}
I could just return the cleansedUtt string i know, but is it possible for me to just append this string to the said textbox from this method, within this class?
I also tried it this way, i wrote a class that takes in the name of the textbox and string to append to that textbox. it works BUT only on the default.aspx page and does not recognise the textbox names within the difference classes. The code is as follows:
public class formControl
{
public static void ModifyText(TextBox textBox, string appendthis)
{
textBox.Text += appendthis + "\r\n";
}
I would suggest you that do not access the Page Controls like TextBox in your class. It will be more useful and a good practice that whatever functionality your class does, convert them into function which accept the parameters and returns some value and then on the basis of that value you can set the controls value.
So now you have reusable function that you can use from any of the page you want. You do not need to write it for every textbox.
Here I am giving you a simple example
public class Test
{
public bool IsValid(string value)
{
// Your logic
return true;
}
}
Now you can use it simple on your page like this
Test objTest = new Test();
bool result=objTest.IsValid(TextBox1.Text);
if(result)
{
TextBox1.Text="Everything is correct";
}
else
{
TextBox1.Text="Something went wrong";
}
If you have your class in the same project (Web Project) the following will work:
public class Test
{
public Test()
{
//
// TODO: Add constructor logic here
//
}
public static void ValidateTextBox(System.Web.UI.WebControls.TextBox txt)
{
//validation logic here
if (txt != null)
txt.Text = "Modified from class";
}
}
You can use this from your webform like this:
protected void Page_Load(object sender, EventArgs e)
{
Test.ValidateTextBox(this.txt);
}
If your class is in a different (class project), you would need to add a reference to System.Web to your project.
I have a question, and it may be because I'm not understanding the way viewstate works. I have some code that sets a viewstate variable in the setter for a property in a custom control I have made.
public bool EditMode
{
get { return (bool)(ViewState["editMode" + this.ID] ?? false); }
set {ViewState["editMode" + this.ID] = value;}
}
The editmode is being set during a button click event.
public void shippingButton_Click(object sender, EventArgs e)
{
if (((Button)sender).CommandName== "Edit")
{
ctrlShippingAddress.EditMode = true;
}
else
{
Page.Validate();
if (Page.IsValid)
{
ctrlShippingAddress.SaveAddress();
ctrlShippingAddress.EditMode = false;
}
}
}
I've tried manually setting it on page load in case I wasn't adding this to the viewstate at the correct point in the page cycle, but as I understand it events occur before render. I have also tried adding ViewStateMode="Enabled" to the control, then to the page using it, then to the master page with no luck.
If I debug at the point of the get/set I see that viewstate is an empty collection (which doesn't make sense because it's also saving form data that is persisting as it should).
I appreciate any help.
You don't need to append the control ID to the ViewState key. I assume you're doing that for uniqueness, but it's not necessary.
The above may fix your problem, but if not try something like this instead:
public bool EditMode
{
get
{
bool editMode = false;
if (ViewState["editMode"] != null)
editMode = (bool)ViewState["editMode"];
return editMode;
}
set
{
ViewState["editMode"] = value;
}
}
After reviewing with a co-worker I discovered that the issue was in the pages node of the web.config
<pages enableViewState="false">
needed to be set to true
I am trying to make a validator that will make sure that at least 2 items are selected. The validator works correctly on the server side but the client side code never gets executed.
Here is the code:
Sys.Mvc.ValidatorRegistry.validators["country"] = function (rule) {
var min = rule.ValidationParameters["min"];
return function (value, context) {
if (value >= min) return true;
return rule.ErrorMessage;
};
};
And here is the validator code:
public class CountryValidator : DataAnnotationsModelValidator<CustomValidations.CountryAttribute>
{
private int _minimum;
private string _message;
public CountryValidator(ModelMetadata metadata, ControllerContext context, CustomValidations.CountryAttribute attribute) : base(metadata,context,attribute)
{
_minimum = attribute.Minimum;
_message = attribute.ErrorMessage;
}
public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
{
var rule = new ModelClientValidationRule()
{
ErrorMessage = _message,
ValidationType = "country"
};
rule.ValidationParameters.Add("min", _minimum);
return new[] { rule };
}
}
I have even registered the validation adapter in global.asax file:
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
RegisterRoutes(RouteTable.Routes);
DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(AgeAttribute), typeof(AgeValidator));
DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(CountryAttribute),typeof(CountryValidator));
}
I am thinking that the validator only works with the elements that have a value property like textboxes etc.
UPDATE 1:
EnableClientValidation is invoked correctly and all the required JS files are included in the project. It seems like I need to attach the onblur to the context. I will try that and post the results.
<% =Html.EnableClientValidation(); %> needs to be in your view somewhere. Also make sure you reference MicrosoftAjax.js and MicrosoftMvcValidation.js in the same view (before your js function).
Either your missing MicrosoftMvcAjax.js or you need to implement your custom validation in jQuery as described on Mr. Haack's website http://haacked.com/archive/2009/11/19/aspnetmvc2-custom-validation.aspx.
I think it is because the default validation is invoked on the onblur event of the input textbox. And for a listbox this event was not being thrown.
In this tutorial I am reading, Dave Ward creates a page that shows the server date in a label without using the update panel.
I am trying to learn how to create servercontrols that use ajax for partial postbacks where methods within the control are called from clientscript generated by the same control, and I think that learning how to convert this page to a server control would be a help me understand what servercontrols use instead of webmethods to expose their methods to clientscript.
I created the page, codebehind, and javascript exactly as the article indicated and got the sample to work.
So, to start trying to convert this to a servercontrol, I moved Dave's Javascript for the page into a file, ~tests/JScript.js:
function UpdateTime() {
PageMethods.GetCurrentDate(OnSucceeded, OnFailed);
}
function OnSucceeded(result, userContext, methodName) {
$get('Literal1').innerHTML = result;
}
function OnFailed(error, userContext, methodName) {
$get('Literal1').innerHTML = "An error occured.";
}
And put the following class in my App_Code:
namespace foo
{
/// <summary>
/// Summary description for ServerControlTest
/// </summary>
public class ServerControlTest : CompositeControl, IScriptControl
{
ScriptManager sm;
protected override void OnPreRender(EventArgs e)
{
if (!this.DesignMode)
{
// Test for ScriptManager and register if it exists
sm = ScriptManager.GetCurrent(Page);
if (sm == null)
throw new HttpException("A ScriptManager control must exist on the current page.");
sm.RegisterScriptControl(this);
sm.EnablePageMethods = true;
}
base.OnPreRender(e);
}
protected override void OnLoad(EventArgs e)
{
Literal lit = new Literal();
lit.Text = "<span ID=\"Literal1\" runat=\"server\">test</span><input id=\"Button1\" type=\"button\" value=\"button\" onclick=\"UpdateTime();\" />";
this.Controls.Add(lit);
}
protected override void Render(HtmlTextWriter writer)
{
if (!this.DesignMode)
sm.RegisterScriptDescriptors(this);
base.Render(writer);
}
[WebMethod]
public static string GetCurrentDate()
{
return DateTime.Now.ToString();
}
#region IScriptControl Members
IEnumerable<ScriptDescriptor> IScriptControl.GetScriptDescriptors()
{
return null;
}
IEnumerable<ScriptReference> IScriptControl.GetScriptReferences()
{
ScriptReference reference = new ScriptReference();
reference.Path = ResolveClientUrl("~/tests/JScript.js");
return new ScriptReference[] { reference };
}
#endregion
}
}
Now, in my sample page, when I click the button, I get this error:
PageMethods is not defined
[Break on this error] PageMethods.GetCurrentDate(OnSucceeded, OnFailed);
How do I call GetCurrentDate from the clientscript that my control registers?
There is actually no fully encapsulated method for implementing AJAX callbacks against methods of a server control yet, as of v3.5. It's a very frustrating limitation.
The most common solution is to create an HttpHandler in your server control's assembly, then require that the handler be registered in the web.config. Look at how ASP.NET AJAX's ScriptResource.axd is wired up in the web.config in ASP.NET AJAX 1.0, for example.
I have an extender control that raises a textbox's OnTextChanged event 500ms after the user has finished typing. The problem with this is that OnTextChanged gets raised when the textbox loses focus, which causes problems (because of the postback).
What I'd like to do is give the extender control its own server-side event (say, OnDelayedSubmit) so I can handle it separately. The event will originate in the extender control's behavior script (after the 500ms delay), so putting a __doPostBack in onchanged is not an option.
Can anyone shed light on how to go about this?
After plenty of reading up on extender controls and JavaScript, I've cobbled together a solution that seems to be working so far.
The main trick was getting the necessary postback code from server-side to the client-side behavior script. I did this by using an ExtenderControlProperty (which is set in the control's OnPreRender function), and then eval'd in the behavior script. The rest was basic event-handling stuff.
So now my extender control's .cs file looks something like this:
public class DelayedSubmitExtender : ExtenderControlBase, IPostBackEventHandler
{
// This is where we'll give the behavior script the necessary code for the
// postback event
protected override void OnPreRender(EventArgs e)
{
string postback = Page.ClientScript.GetPostBackEventReference(this, "DelayedSubmit") + ";";
PostBackEvent = postback;
}
// This property matches up with a pair of get & set functions in the behavior script
[ExtenderControlProperty]
public string PostBackEvent
{
get
{
return GetPropertyValue<string>("PostBackEvent", "");
}
set
{
SetPropertyValue<string>("PostBackEvent", value);
}
}
// The event handling stuff
public event EventHandler Submit; // Our event
protected void OnSubmit(EventArgs e) // Called to raise the event
{
if (Submit != null)
{
Submit(this, e);
}
}
public void RaisePostBackEvent(string eventArgument) // From IPostBackEventHandler
{
if (eventArgument == "DelayedSubmit")
{
OnSubmit(new EventArgs());
}
}
}
And my behavior script looks something like this:
DelayedSubmitBehavior = function(element) {
DelayedSubmitBehavior.initializeBase(this, [element]);
this._postBackEvent = null; // Stores the script required for the postback
}
DelayedSubmitBehavior.prototype = {
// Delayed submit code removed for brevity, but normally this would be where
// initialize, dispose, and client-side event handlers would go
// This is the client-side part of the PostBackEvent property
get_PostBackEvent: function() {
return this._postBackEvent;
},
set_PostBackEvent: function(value) {
this._postBackEvent = value;
}
// This is the client-side event handler where the postback is initiated from
_onTimerTick: function(sender, eventArgs) {
// The following line evaluates the string var as javascript,
// which will cause the desired postback
eval(this._postBackEvent);
}
}
Now the server-side event can be handled the same way you'd handle an event on any other control.