Application

Wisej.Web.Application

Namespace: Wisej.Web

Assembly: Wisej.Framework (3.5.0.0)

Represent a Wisej application session. Provides methods and events to manage the application in the context of the current session.

public class Application : IWisejComponent, IDisposable, IWisejSynchronized

This class provides several static methods, properties and events that allow the application to manage all sorts of features related to the current session:

  • Save and retrieve session variable. Use Session to store and retrieve session variable. The property is a dynamic object and a Dictionary, therefore you can access its properties directly or through the indexer.


    Application.Session.myValue = 12;
    Application.Session["myValue"] = 12;
  
  • Manage cookies. Use Cookies to manage browser's cookies.

  • Read server variables. Use ServerVariables to retrieve all the data made available by the server. Some of the variables in the collection are also available directly: ServerPort, ServerName, UserAgent, etc.

  • Read the application's URL. Use Uri, Url, StartupUri, and StartupUrl.

  • Read the application's system information. Use StartupPath, ProductName, ProductVersion, etc.

  • Retrieve browser related information. Use the Browser to read the client browser type, OS, version, capabilities, screen size, browser size, language, and state. The Browser object is updated automatically when the user resizes the browser or the page is reloaded.

  • Control the client browser. Start a Download, execute JavaScript functions or scriptlets using Call or Eval. Make the browser navigate to a different URL using Navigate or simply Reload the page.

  • Manage the main page or current desktop. MainPage lets you change the Page object that fills the browser and "navigate" from page to page. Desktop lets you change the active Desktop object on the client browser.

  • Manage all live components in the session. Through the Application class you can find, iterate, inspect all live components of any type. See OpenForms for all the currently created (visible or invisible) instances of Form. OpenPages returns all the created Page objects. FindComponent and FindComponents provide an easy way to find any component in the session or to iterate the list of components that match a custom expression.

  • Start background tasks in context. StartTask provides a powerful way to start a background task on the server that can keep interacting with the client browser while running independently.

  • Manage the application's theme. Use LoadTheme to load a Wisej theme into the application. Or use the Theme object to read all sorts of information from the current ClientTheme.

  • Terminate the application without waiting for the session to timeout. Use Exit to terminate the current session and free all the related memory.

There is a lot more exposed by the Application class. You can inspect all the properties and methods in Visual Studio through IntelliSense or online at docs.wisej.

Properties

ClientProfile: Returns or sets the current client responsive profile.

This is the profile that best matches the current browser on the client. It is updated automatically on every request.

ClientBrowser: Returns or the client browser's information.

X509Certificate2: EXPERIMENTAL: Provides the client certificate fields issued by the client in response to the server's request for the client's identity. Since 3.5.6

String: Returns the current unique client id.

ClientCollection: Returns a collection of all the unique client browsers using the application.

CommandManager: Returns the current CommandManager.

String: Returns the path for the application data that is shared among all users.

RegistryKey: Returns the registry key for the application data that is shared among all users.

String: Returns the company name associated with the application stored in the AssemblyCompanyAttribute.

Configuration: Returns the current Configuration.

CookieCollection: Collection of cookies.

IWisejComponent: Returns the application component instance that an application can store and use later to restore the context when updating client widgets during an out-of-bound call using the Update method.

Threads that are not started using StartTask don't have any knowledge of the current session and don't have a way to communicate with the client The Current property returns the instance of the Application class that is bound to the current session. It can be used just like any other component with the method Update or RunInContext to restore the session for the current thread. The advantage of using Current instead of the instance of a control or a page is to avoid to keep a reference to a component that may be disposed by the application.


var current = Application.Current;
var thread = new Thread(() => {
  Application.Update(current, () => {
  
    // code here is running in context.
    
  });
});

CultureInfo: Returns or sets the current CultureInfo for the session.

Desktop: Returns or sets the current Desktop.

Boolean: Returns or sets whether the browser will ask the user to confirm unloading the current page.

This property attaches the window.onbeforeunload event. See https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onbeforeunload. It's not possible to determine whether the page is being unloaded because the user is trying to close the tab, close the browser, or is refreshing the page, or is taking any other action that may reload the page.

String: Returns the path for the application's main assembly.

Image: Returns or sets the favicon to display in the browser.

String: Returns or sets the URL to the favicon to display in the browser.

String: Returns or sets the hash part of the URL on the client.

Boolean: Returns a value indicating whether the session has been authenticated.

Boolean: Indicates that the current application instance, which corresponds to the session, has been terminated and disposed.

Boolean: Returns true when the current session has expired.

Boolean: Returns true if this session is running in secure mode (https:// and wss://)

Boolean: Returns true when the current session has been terminated.

Boolean: Returns true if the current session is connected using WebSocket.

Object: Returns a dynamic object containing the currently loaded license information. Since 3.1.3

These are the currently available fields (may change in future releases):

  • Valid: Whether the license is valid. Note that a license may be expired and valid if the product release date is within the license expiration date.

  • LicenseKey: License key loaded from web.config or assigned to LicenseKey.

  • ProductName: Full name of the licensed product.

  • CustomerName: Name of the registered customer that owns the license.

  • ExpirationDate: Expiration date for the product free updates.

Retrieve the values either using a dynamic object or a property indexer:


  string productName = Application.LicenseInfo.ProductName;
  string customerName = Application.LicenseInfo["CustomerName"];

String: Returns or sets the runtime server license key.

Setting the LicenseKey programmatically has to be done before the application is loaded. The best place is the static constructor for the Program static class, or the static constructor of the main window (if defined in Default.js).


static class Program
{
  static Program()
  {
    Application.LicenseKey = "...";
  }
}

Page: Returns or sets the current full page window.

FormCollection: Returns a collection of open forms owned by the application.

PageCollection: Returns a collection of open pages owned by the application.

ClientPlatform: The name of the currently loaded platform.

String: Returns the product name associated with this application.

String: Returns the product version associated with this application stored either in AssemblyInformationalVersionAttribute or AssemblyFileVersionAttribute.

NameValueCollection: Returns the parameters used to launch the application.

Boolean: Returns or sets whether all the controls in the applications should operate using the right-to-left mode.

The value of this property is updated automatically when the current language changes if the value of "rightToLeft" in the application configuration file is set to "auto".

Boolean: Returns true when the application is running in not in design, debug or test mode.

String: Returns the server's host name, DNS alias, or IP address as it would appear in self-referencing URLs.

Int32: Returns the port number to which the request was sent.

NameValueCollection: Returns the server variables.

ServiceProvider: Returns the ServiceProvider implementation used by Wisej.NET to manage Dependency Injection across the application. Since 3.1

Object: Provides a generic storage for session-based objects.

Int32: Returns the total number of currently active sessions.

String: Returns the unique current session ID.

Boolean: Shows or hides the debug console on the browser.

Displays a simple HTMl only debug console. Works with any browser also when the developer tools are not available.

Boolean: Returns or sets whether the browser is blocked by the Ajax loader.

String: Returns the root path of the web application.

Uri: Returns the URI used to start the application.

String: Returns the URL used to start the application.

ClientTheme: Returns or sets the current ClientTheme.

You can create and modify a new custom theme using the ClientTheme class. The new theme can be based on an existing theme, can be empty, or can be initialized from a JSON string.


// create a new custom theme cloned from the current theme.
var myTheme = new ClientTheme("MyTheme", Application.Theme);

// alter the buttonFace color.
myTheme.Colors.buttonFace = "red";

// update the current session using the new custom theme.
Application.Theme = myTheme;

You may also alter a global theme shared by all sessions.



// change the buttonFace color in the current theme.
// if the theme is one of the global themes, i.e. it was loaded
// using Application.LoadTheme(name), then the change is also global.
Application.Theme.Colors.buttonFace = "red";

// since the theme objects are all dynamic and use a special DynamicObject
// class part of the Wisej Framework, you can also use a string indexer
// to address any field.
Application.Theme.Colors["buttonFace"] = "red";

String: Returns or sets the page title in the browser.

Uri: Returns the current Uri used either to launch or reload the application. It may be different from StartupUri.

String: Returns the current URL used either to launch or reload the application. It may be different from StartupUrl.

IPrincipal: Returns the security information for the current request.

String: Returns the raw user agent string of the client browser.

String: Returns the IP host address of the remote client.

String: Returns the DNS name of the remote client.

WindowsIdentity: Returns the WindowsIdentity type for the current user.

String[]: Gets a sorted string array of client language preferences.

Methods

Adds an event filter to monitor all the incoming events before they are routed to their respective component.

ParameterTypeDescription

filter

An object that implements the IEventFilter interface to add to the filter list.

Adds the text and corresponding translation to the default locale on the client.

ParameterTypeDescription

text

The text to translate.

translation

The translation override.

Instructs the browser to display a dialog with an optional message, and to wait until the user dismisses the dialog.

ParameterTypeDescription

message

A string you want to display in the alert dialog.

Returns: Task. An awaitable Task that represents the asynchronous operation.

Executes the JavaScript function on the client.

ParameterTypeDescription

function

The name of the function to execute.

args

The arguments to pass to the function.

Executes the JavaScript function on the client and receives the return value (or null) in the callback method.

ParameterTypeDescription

function

The name of the function to execute.

callback

Asynchronous callback method that receives the return value.

args

The arguments to pass to the function.

Asynchronously executes the JavaScript function on the client and returns an awaitable Task with the result of the remote call.

ParameterTypeDescription

function

The name of the function to execute.

args

The arguments to pass to the function.

Returns: Task<Object>. An awaitable Task that represents the asynchronous operation.

Cancels the fullscreen mode.

Instructs the browser to display a dialog with an optional message, and to wait until the user either confirms or cancels the dialog. until the user dismisses the dialog.

ParameterTypeDescription

message

A string you want to display in the confirm dialog.

Returns: Task<Boolean>. An awaitable Task that represents the asynchronous operation.

Downloads the specified file on the client.

ParameterTypeDescription

filePath

The file to download.

The name of the file to save on the client.

Optional callback invoked when fileName is downloaded.

Downloads the specified image to the client.

ParameterTypeDescription

image

The image to download.

fileName

The name of the file to save on the client.

Optional callback invoked when fileName is downloaded.

Downloads the bytes in the stream to the client.

ParameterTypeDescription

stream

The stream to send to the client.

fileName

The file name the client will use to save the stream.

Optional callback invoked when fileName is downloaded.

Downloads the specified file on the client.

ParameterTypeDescription

target

Specifies where to open the file. Leave empty or use "_self" to open in the current tab, _blank to open in a new tab.

filePath

The file to download.

The name of the file to save on the client.

Optional callback invoked when fileName is downloaded.

Downloads the specified image to the client.

ParameterTypeDescription

target

Specifies where to open the file. Leave empty or use "_self" to open in the current tab, _blank to open in a new tab.

image

The image to download.

fileName

The name of the file to save on the client.

Optional callback invoked when fileName is downloaded.

Downloads the bytes in the stream to the client.

ParameterTypeDescription

target

Specifies where to open the file. Leave empty or use "_self" to open in the current tab, _blank to open in a new tab.

stream

The stream to send to the client.

fileName

The file name the client will use to save the stream.

Optional callback invoked when fileName is downloaded.

Stops the polling requests from the client.

Executes the JavaScript script on the client.

ParameterTypeDescription

script

The script to evaluate.

Executes the JavaScript script on the client and receives the return value (or null) in the callback method.

ParameterTypeDescription

script

The script to evaluate.

callback

Asynchronous callback method that receives the return value.

Asynchronously executes the JavaScript script on the client and returns an awaitable Task with the result of the remote call.

ParameterTypeDescription

script

The script to evaluate.

Returns: Task<Object>. An awaitable Task that represents the asynchronous operation.

Terminates the application and the corresponding session.

Find the first component that matches the conditions defined in the predicate function.

ParameterTypeDescription

match

A custom Predicate expression used to match the IWisejComponent to find.

Returns: IWisejComponent. The first IWisejComponent qualified by the match expression.

This method lets an application find any live component in the current session.


  // Find the first component that is a Button with Text = "OK"
  var button = Application.FindComponent(c => c is Button && ((Button)c).Text == "OK");

Finds all the components that match the conditions in the predicate function.

ParameterTypeDescription

match

A custom Predicate expression used to match the list of IWisejComponent objects to find.

Returns: IList<IWisejComponent>. The list of IWisejComponent instances qualified by the match expression.

This method lets an application iterate through all the live components in the current session.


  // List all text boxes that are read only in all forms.
  var list = Application.FindComponents(c => c is TextBox && ((TextBox)c).ReadOnly);

Returns a session-static instance of T . Since 3.2.7

ParameterTypeDescription

T

Type of the singleton object.

Thread-static reference to the T singleton.

Optional method for the creation of an instance of T .

Returns: T. The singleton instance of T associated with the current session.

This utility method simplifies the management of session-static (or session singleton) instances. It should be used to convert traditional static variables to session-static instances when changing an application designed for single users to a multi-user system. The code below shows how to use this feature together with the ThreadStaticAttribute to manage session-static instances and, at the same time, improve the speed of the code that relies on the singleton objects. Using the ThreadStaticAttribute backing field allows the code that retrieves the session-static instance to quickly check the last instance and compare the session id and avoid accessing the dictionary for every access within the same request. Otherwise the code would have to always store a local variable in order to speed up multiple operations using the same static field.



public class MyStatics {

  // Thread-static singleton.
  [ThreadStatic] private static SessionReference<MyStatics> _instance;
  
  // Previously static fields (or properties).
  public int Counter;

  // Session singleton.
  public MyStatics Instance
    => Application.GetInstance(ref _instance);
    
  public static void DoSomething()
  {
    // was MyStatics.Counter++;
    MyStatics.Instance.Counter++;
  }
}

If the class a private constructor (to simulate a static class) or required initialization code or arguments, use the optional builder method:



public class MyStatics {

  private MyStatics() { };
  
  // Thread-static singleton.
  [ThreadStatic] private static SessionReference<MyStatics> _instance;
  
  // Previously static fields (or properties).
  public int Counter;

  // Session singleton.
  public MyStatics Instance
    => Application.GetInstance(ref _instance, () => new MyStatics());
    
  public static void DoSomething()
  {
    // was MyStatics.Counter++;
    MyStatics.Instance.Counter++;
  }
}

Loads an assembly given the file name or path.

ParameterTypeDescription

nameOrFile

The file name or full path for the assembly to load.

Returns: Assembly. The loaded Assembly.

This method loads the assembly and, if the assembly contains Wisej components that need embedded resources - like JavaScript classes or CSS styles - that are embedded in the assembly, notifies the client with the URL to load the additional resources dynamically.

Creates an instance of the specified component from the assembly.

ParameterTypeDescription

nameOrFile

The file name or full path for the assembly to load.

className

Returns: IWisejComponent. An instance of a Wisej component implementing the IWisejComponent interface.

ParameterTypeDescription

packages

ParameterTypeDescription

packages

Returns: Task<Boolean>.

Changes the current theme.

ParameterTypeDescription

name

Name of the theme resource. Use only the name without the path and without the extension.

Optional list of theme mixins. If null, the default theme mixins are always applied.

Returns the full file path in relation to the application's project directory.

ParameterTypeDescription

path

Returns: String. The full path relative to the current application's root directory.

Navigate to the specified URL.

ParameterTypeDescription

url

URL to navigate to.

The target browser window: _self, _blank, etc.

Navigate to the specified URL in a new browser tab and receive an optional callback when the tab is closed.

ParameterTypeDescription

url

URL to navigate to.

target

The target browser window, cannot be _self and cannot be empty.

onclose

Callback function invoked when the browser tab is closed. Can be null.

Opens the specified URL in a browser's popup window and receive an optional callback when the tab is closed.

ParameterTypeDescription

url

URL to navigate to.

target

The target browser window, cannot be _self and cannot be empty.

windowFeatures

A string containing a comma-separated list of window features in the form name=value — or for boolean features, just name. These features include options such as the window's default size and position, whether or not to open a minimal popup window, and so forth.

onclose

Callback function invoked when the browser popup window is closed. Can be null.

Plays one of the built-in sounds

ParameterTypeDescription

type

One of MessageBoxIcon value that identifies the sound to play.

Plays a sound.

ParameterTypeDescription

soundUrl

A string representing either a sound file URL or a base64 data URL.

Executes the callback method after all processing is completed and before updating the client.

ParameterTypeDescription

callback

Method to invoke after the request has completed but before sending the response to the server.

The Post() method is similar to the BeginInvoke() method used by desktop applications. It allows you to execute a block of code out of sync with the current execution flow.



void Test() {

  Application.Post(() => {
    this.listBox.Items.Add("1");
  });
  
  this.listBox.Items.Add("2");
  
  // The items will be added in this order: "2", "1".
}

Prints the specified control.

ParameterTypeDescription

control

The control to print, can be a window, a page or a single control.

The control is printed without the caption or the borders, if present.

Prints the entire browser window.

Instructs the browser to display a dialog with an optional message prompting the user to input some text, and to wait until the user either submits the text or cancels the dialog.

ParameterTypeDescription

message

A string of text to display to the user.

An optoional string containing the default value displayed in the text input field.

Returns: Task<String>. An awaitable Task that represents the asynchronous operation.

Generates a new session id without losing the session. Since 3.5.2

Use this method after a successful login to prevent potential session fixation attacks.

Causes the application to reload on the browser.

Removes the filter from the list of registered event filters.

ParameterTypeDescription

filter

An object that implements the IEventFilter interface to remove from the filter list.

Requests the browser to enable fullscreen mode if supported.

Executes the callback in context.

ParameterTypeDescription

context

The application context to update. It can be any Wisej component or the IWisejComponent returned by the property Current.

action

Function to execute in context. The code in the function can access all the static Application properties when executed from an out-of-bound thread.

Replaces the object assigned to a session-static singleton. Since 3.5.2

ParameterTypeDescription

T

Type of the session-static object.

Thread-static reference to the T singleton.

instance

New value to assign to the session-static storage.

Sets the current session timeout in seconds.

ParameterTypeDescription

seconds

Instructs the client to start polling the server for UI changes at the specified interval when a WebSocket connection is not available.

ParameterTypeDescription

interval

Polling interval in milliseconds. The minimum is 1000ms.

Calling this method when IsWebSocket is true has no effect. Use client side polling when you know that your code will start a background task that needs to update the client asynchronously (push updates) and your server or clients don't support WebSocket connections. Once the background tasks are completed call EndPolling to reduce the incoming requests from the client.



// this has not effect when the client and server are connected using WebSocket.
Application.StartPolling(1000);

Application.StartTask(() => {

  for (int i = 0; i < 100; i++) {
    this.label1.Text = "Counting..." + i;
    Thread.Sleep(1000);
  }
  
  // this has not effect when the client and server are NOT connected using WebSocket.
  Application.Update(this);

  // this has not effect when the client and server are connected using WebSocket.
  Application.EndPolling();

});

Throws:

Starts a new task within the current application context and returns immediately. See also background-tasks.

ParameterTypeDescription

action

Start method invoked by the new task when it starts up.

Returns: Task. An awaitable Task.

The task runs in the background but it's still capable of updating the client asynchronously when working with WebSocket by calling the Update method to push the UI updates to the client browser. If you want to support background updates for clients or servers that can't use the WebSocket connection, you can either add a Timer component to the parent container to force period requests to the server, or you can use the StartPolling and EndPolling methods.


Application.StartTask(() => {

  for (int i = 0; i < 100; i++) {
  
    this.label1.Text = "Counting..." + i;
    
    // just wait a bit or it's too fast.
    Thread.Sleep(1000);
    Application.Update(this);
  }
});

Starts a new task with a return value within the current application context and returns immediately. See also background-tasks.