WEBfactory 2010

<UserControl x:Class="ClientSDKExample.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="296" d:DesignWidth="451">

    <Grid x:Name="LayoutRoot" Background="White" VerticalAlignment="Center" HorizontalAlignment="Center">
        <StackPanel Orientation="Horizontal">
            <StackPanel Orientation="Vertical" Margin="2">
                <TextBlock Text="Register and Read" FontWeight="Bold"></TextBlock>
                <TextBlock Name="SignalValueLabel"></TextBlock>
            </StackPanel>
            <StackPanel Orientation="Vertical" Margin="2">
                <TextBlock Text="Write" FontWeight="Bold"></TextBlock>
                <TextBox Name="SignalInput" KeyUp="SignalInput_KeyUp"></TextBox>
            </StackPanel>
            <StackPanel Orientation="Vertical" Margin="2">
                <TextBlock Text="Internationalization" FontWeight="Bold"></TextBlock>
                <TextBlock Name="SymbolicTextLabel"></TextBlock>
                <Button Name="ENButton" Content="EN" Click="ENButton_Click"></Button>
                <Button Name="DEButton" Content="DE" Click="DEButton_Click"></Button>
            </StackPanel>
            <StackPanel Orientation="Vertical" Margin="2">
                <TextBlock Text="Security" FontWeight="Bold"></TextBlock>
                <TextBox Name="UserNameBox" />
                <PasswordBox Name="PasswordBox" />
                <Button Name="LoginButton" Content="Log in" Click="LoginButton_Click"></Button>
                <Button Name="LogoutButton" Content="Log out" Click="LogoutButton_Click"></Button>
                <TextBlock Text="Logged user:" FontWeight="Bold"></TextBlock>
                <TextBlock Name="UserLabel"></TextBlock>
                <TextBlock Text="Project Authorizations:" FontWeight="Bold"></TextBlock>
                <TextBlock Name="ProjectAuthorizationsLabel"></TextBlock>
                <TextBlock Text="System Authorizations:" FontWeight="Bold"></TextBlock>
                <TextBlock Name="SystemAuthorizationsLabel"></TextBlock>
            </StackPanel>
        </StackPanel>
    </Grid>
</UserControl>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using WFSilverlight.Core;

namespace ClientSDKExample
{
    public partial class MainPage : UserControl, IDisposable
    {
        public MainPage()
        {
            InitializeComponent();
            Loaded += UserControl_Loaded; //register to the Loaded event of the UserControl
        }

        private WFConnector wfConnector;
        private const string SignalName = "Setpoint 2";
        private string[] MySymbolicTexts = new string[] { "SymbolicText" };

        //REGISTER and READ operations start here
        private void UserControl_Loaded(object sender, RoutedEventArgs e) //here is what happens when the UserControl is loaded
        {
            if (!System.ComponentModel.DesignerProperties.GetIsInDesignMode(this)) //the next code will happen only at run time
            {
                wfConnector = new WFConnector(false); //initializing new connector instance
                wfConnector.RegisterSignalChangedHandler("", SignalName, SignalChanged); 
		//registering to the signal changed event handler
                wfConnector.RegisterLanguageChangedHandler(MySymbolicTexts, OnLanguageChanged); 
		//registering to the language changed event handler
                wfConnector.UserContextChanged += UserContextChanged; //registering to the user context changed event handler
            }
        }

        void SignalChanged(string name, object value) //the delegate method from the RegisterSignalChangedHandler event handler
        {
            if (value != null)
            {
                SignalValueLabel.Text = value.ToString(); //write the value to the label if it is not null
            }
        }
        
        //WRITE operations start here
        private void SignalInput_KeyUp(object sender, KeyEventArgs e) 
	//the Key Up event handler method for the SignalInput text block
        {
            if (e.Key == Key.Enter) //checking if the Entery key is pressed used
            {
                wfConnector.WriteSignal("", SignalName, SignalInput.Text, WriteSignalHandler); 
		//writing the value to the signal
            }
        }

        private void WriteSignalHandler(Exception error, int[] results) //validating the write operation
        {
            var errorCode = results == null ? 0 : results.FirstOrDefault();

            if (!IsWritingSuccessful(error, results)) //displaying the error code if the writing is not succesful
            {
                string errorMessage = error != null
                                            ? error.Message
                                            : "Write failed with error code: " + errorCode;

                MessageBox.Show(errorMessage); //
            }
        }

        private bool IsWritingSuccessful(Exception error, IEnumerable<int> results) 
	//the method that checks if any error code returned when writing
        {
            var errorCode = results == null ? 0 : results.FirstOrDefault();
            return error == null && errorCode == 0;
        }

        //INTERNATIONALIZATION operations start here
        private void OnLanguageChanged(string[] symbolicNames, string[] translationTexts) 
	// the method that writes the translations to the SymbolicTextLabel
        {
            SymbolicTextLabel.Text = translationTexts[0];
        }
        
        private void ENButton_Click(object sender, RoutedEventArgs e)
        {
            wfConnector.SetLanguageId(9); //setting the English language on the Click event
        }

        private void DEButton_Click(object sender, RoutedEventArgs e)
        {
            wfConnector.SetLanguageId(7); //setting the German language on the Click event
        }

        //SECURITY operations start here

        private void UserContextChanged(string userName) //handling the user context changed event
        {
            EnforceAuthorization(); //calls the method that will enforce authorization on the SignalInput

            ObtainProjectAuthorizations(); //calls the method that gets and displays the project authorizations
            ObtainSystemAuthorizations(); //calls the method that gets and displays the system authorizations

            if (string.IsNullOrEmpty(userName)) //checks if the user name is null or empty
            {
                UserLabel.Text = "No logged user"; //if null or empty, displays the text
            }
            else
            {
                UserLabel.Text = userName; //if not null or empty, displays the user name
            }
        }

        private void LoginButton_Click(object sender, RoutedEventArgs e) //the event handler for the Click event
        {
            Login(UserNameBox.Text, PasswordBox.Password); //calls the Login method and passes teh user name and password to it
        }

        private void Login(string userName, string password) 
	//the Login method tries to initialize the login procedure with the provided user name and password
        {
            try
            {
                TryLogin(
                    userName,
                    password);
            }
            catch (Exception ex)
            {
                MessageBox.Show(string.Format("{0} {1}", GetType().Name, ex.Message)); //displays any error that might occur
            }
        }

        private void TryLogin(string userName, string password) 
	//if the user name is valid, calls the LoginUser method of the connector and calls a result handler
        {
            if (string.IsNullOrEmpty(userName)) return;

            wfConnector.LoginUser(
                userName,
                password,
                OnLoginResultHandler);
        }

        private void OnLoginResultHandler(Exception error, int[] results) 
	//this handler calls another method to handle the login results
        {
            HandleLoginAttemptResult(error, results);
        }

        private void HandleLoginAttemptResult(Exception error, int[] results) 
	//checks for error codes and fires the success or failiure methods
        {
            var errorCode = results == null ? 0 : results.FirstOrDefault();

            if (!IsSuccessful(error, results))
            {
                HandleLoginAttemptFailure(error, errorCode);
            }
        }

        private bool IsSuccessful(Exception error, IEnumerable<int> results) 
	//this success method is true when no errors occur and the error code is 0
        {
            var errorCode = results == null ? 0 : results.FirstOrDefault();
            return error == null && errorCode == 0;
        }

        private void HandleLoginAttemptFailure(Exception error, int errorCode) 
	//if success method is false, the failure method is fired
        {
            string errorMessage = error != null
                                        ? error.Message 
	//If there is an error in communicating with the server, the error message will be displayed
                                        : GetTextFromErrorCode(errorCode); 
	//If there was no error in communicating with the server, it will display the text for an error code

            MessageBox.Show(errorMessage);
        }

        private string GetTextFromErrorCode(int errorCode) //this method interprets the error codes in human readable language
        {
            if (errorCode == 0) return "Login attempt failed";

            string translation = null;

            switch (errorCode) //in case of these error codes, here are the translations
            {
                case -404:
                    translation = "Login failed - cannot obtain current logged in user name";
                    break;
                case -4082:
                    translation = "Login failed - the number of failed logins exceeded. Username blocked.";
                    break;
                case -4086:
                    translation = "Login failed - invalid command syntax";
                    break;

                case -4087:
                    translation = "Login failed - expired password";
                    break;

                case -4089:
                    translation = "Login failed - internal server error";
                    break;

                case -4090:
                    translation = "Login failed - max count reached";
                    break;

                case -4091:
                    translation = "Login failed - invalid username or password";
                    break;

                case -4092:
                    translation = "Login failed - already logged on";
                    break;

                case -4094:
                    translation = "Login failed - invalid username or password";
                    break;

                default:
                    translation = "Login attempt failed";
                    break;
            }

            return translation;
        }

        private void LogoutButton_Click(object sender, RoutedEventArgs e) 
	//the click event of the logout button calls the logout method
        {
            Logout();
        }

        private void Logout() 
	//this method tries to log out the user using the connector's LogoutUser method and catches and displays exceptions
        {
            try
            {
                wfConnector.LogoutUser();
            }
            catch (Exception ex)
            {
                MessageBox.Show(string.Format("{0} {1}", GetType().Name, ex.Message));
            }
        }

        private void EnforceAuthorization() 
	//this method disables the SignalInput TextBox if the user's authorizations are not correct
        {
            SignalInput.IsEnabled = wfConnector.CheckProjectAuthorization("Administration");
        }

        private void ObtainProjectAuthorizations() 
	//obtains the project authorizations of the logged in user and passes them as a list of strings to the correct TextBlock
        {
            List<string> UserProjectAuthorizationsList = wfConnector.GetProjectAuthorizations();
            string UserProjectAuthorizations = string.Join("\r\n", UserProjectAuthorizationsList.ToArray());
            ProjectAuthorizationsLabel.Text = UserProjectAuthorizations;
        }

        private void ObtainSystemAuthorizations() 
	//obtains the system authorizations of the logged in user and passes them as a list of strings to the correct TextBlock
        {
            List<string> UserSystemAuthorizationsList = wfConnector.GetSystemAuthorizations();
            string UserSystemAuthorizations = string.Join("\r\n", UserSystemAuthorizationsList.ToArray());
            SystemAuthorizationsLabel.Text = UserSystemAuthorizations;
        }

        //DISPOSE section starts here
        public void Dispose() //the Dispose method from IDisposable
        {
            DisposeConnector();
        }

        private void DisposeConnector()
        {
            if (wfConnector == null) return; //checking if the connector is null
            wfConnector.UnregisterSignalChangedHandler("", SignalName, SignalChanged); 
		//unregistering from the signal changed event handler
            wfConnector.UnregisterLanguageChangedHandler(MySymbolicTexts, OnLanguageChanged); 
		//unregistering from the language changed event handler
            wfConnector.UserContextChanged -= UserContextChanged; 
		//unregistering from the user context changed event handler

            wfConnector.Dispose(); //disposing the connector
            wfConnector = null; //setting the connector to null so it won't be disposed again
        }
    }
}