Windows 10 требует создать учетную запись

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#include<windows.h>
#include <iostream>
#include<algorithm>
 
int main()
{
    std::cout << std::min(1,2);
}

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WinForms to Web: Migrating Desktop Applications, Part 1

Introduction

This is the first part of a series of articles that describes the various migration options of desktop/smart client applications to the web available using Visual WebGui.

To discuss the migration process of legacy desktop applications to the web, you should first be aware of three different types of desktop applications:

1. WinForms-based desktop application (C#/VB.NET): The UI layer is coded using .NET languages—the business can be .NET, COM+, or any other interop.
2. VB 6.0-based applications: The UI layer is coded with VB 6.0.
3. Smart client or other desktop technologies (C++ MFC/ATL, Delphi, Java, and so forth): Any other smart client technology based applications.

This document describes the migration process of WinForms-based desktop applications to the web using Visual WebGui.

WinForms-Based Desktop Applications: Background

Normally, without Visual WebGui the migration process of a WinForms desktop application to the web will require a full re-engineering of the UI layer to fit the web architecture and capabilities.

If you take WinForms migration to ASP.NET, for example, using any AJAX third-party controls to provide a rich UI experience, you will have to consider:

1. Entirely new API.
2. Entirely new update approach.
3. Entirely new look & feel—or work hard to customize the UI to look the same.
4. Lighten the amount of data transferred to the client and presented at any given time to avoid severe latency.
5. Compromise on features list due to the web limitations.
6. Handle security holes created as a result of opening services consumed by client-side AJAX and transferring business logics to the client.

The Visual WebGui SDK is fully integrated with Visual Studio and provides the exact same API and set of tools/capabilities that are provided out of the box with WinForms 1.0 and 2.0. This fact enables the native capability of simply copying any existing WinForms source code to a VWG project and providing a fully functional equivalent web application.

The Process

The three basic steps of migration (view a walkthrough tutorial):

1. Open a new Visual WebGui application.
2. Copy the code from your WinForms project into this new web application.
3. Replace any reference to the WinForms API namespace (“System.Windows.Forms”) within the code to Visual WebGui API reference (“Gizmox.WebGUI.Forms”).

Any standard WinForms application that uses the 58 WinForms out-of-the-box controls will then compile and execute as a plain web application.

The outcome of this short process is an ASP.NET-based solution in terms of deployment and runtime and has the following properties:

1. Deployment is a copy & paste equivalent to an ASP.NET web site.
2. Server infrastructure requires an IIS and .NET CLR only.
3. The application can be consumed from any plain browser—no installation is made on the client.
4. Minor static and cached footprint on the client— ~200kb of plain JS and HTML code due to the Empty Client concept.
5. Support for multiple presentation layers with the same code base (DHTML/Silverlight or Smart Client).
6. Maintain a single layer of code—no need to write or maintain JavaScript, HTML, and services.
7. Highly secured due to the Empty Client concept.

Considerations & Exceptions

There are three major setbacks you might have during the process that you can quantify in advance and estimate the amount of work that has to be done to migrate your application:

1. Minor differences between the VWG API and WinForms that are mainly caused by architecture differences.
2. The amount of third-party controls that are used in your application. This section describes a situation of using some non-WinForms out-of-the-box controls (for example, Infragistics or DevExpress controls, and so on). In those cases, you can select the most suitable solution from the following three options:
1. Choose a similar control from the WinForms out of the box, adjust your code to use it, and then perform the migration process.
2. Select an equivalent third-party ASP.NET control (Infragistics, Telerik, DevExpress, and the like) that provides the same functionality, wrap it by a click of a button in VWG, and adjust your code to use it.
3. Write your own VWG custom control that will perfectly suit your needs and then adjust your code after the migration process to use this control.
3. Adjustments of a single-user desktop application to a multiuser web environment. This section summarizes some of the major issues of transforming a single-user application to a multiuser application sharing the same CPU, memory space, and other resources.
1. Thread safety: Because a WinForms application can contain static members that are accessible to a single user, you should now consider one of the following:
1. Replacing those static members to synchronized multi-thread safe data structures.
2. Lock critical read/write sections to protect concurrent multi user access.
3. Remove the statics and find an instance or DB-based solutions.
2. Memory load: In a desktop application, there might be places when the original consideration of the amount of memory in use was based on the assumption that the executing machine is local. Therefore, many items are loaded to memory simultaneously without limitation. Now, on a shared memory environment, when the server does the heavy lifting, the amount of memory consumed by each user will set the number of concurrent users that can be served by each server.

The following steps are recommended:

1. Consider loading items to memory on demand (keep only the headers and the identifiers in memory).
2. Remove any large objects read to memory. For example, don’t save binary objects to memory; instead, write the binary to the response stream directly to the client.
3. Prefer DB-based paging on entire prefaces and memory-based paging. Visual WebGui provides mechanisms to enable it easily.

Summary

Migration of any WinForms application to the web using Visual WebGui has the following advantages:

1. In three simple steps, you will be able to get very close to a working web application.
2. The effort you have to make to accomplish a fully functional web application is measurable.
3. The application can keep using the existing BL and DL layers; only the UI is either migrated automatically or adjusted.

Introduction

Hello guys, in this article we will create a login and registration form with a database in a C# Windows Form application. This application has three forms, login, registration, and home. Users first register themselves, then log in to their account and see the welcome message on the home page.

Step 1

Open your visual studio, here I will use Visual Studio 2019.

Step 2

The clock on file menu on top of the visual studio, hover mouse on new, and click on Project.

Step 3

Search for Windows Form App (.NET framework) and click on next.

Step 4

In this step, you have to enter some details of your application and then click on the Create button. You have to enter the following details:

1. Project Name: Name of your project
2. Location: Location where you want to store your app on your local computer.
3. Solution Name: This name is displayed in solution explorer in visual studio.
4. Framework: Select the appropriate framework as per your application requirements.

Step 5

Now your project is created. Open Solution Explorer. If you don’t see solution explorer, you can open it from the View menu on top, or you can try the short cut key “Ctrl+W,S”. We need to create some pages for our application. Right-click on the solution name then Hover the mouse on Add and click on Add New Item, or you can user short cut key “Ctrl+Shift+A”.

Step 6

Now you see a dialog where we add our forms. Select Windows Form, give it a proper name and click on Add. Add a Login, Registration, and Home page in the same way.

Step 7

Now we need to add a database in our project. Right-click on the solution name, then Hover mouse on Add and click on Add New Item, or you can user short cut key “Ctrl+Shift+A”. Select data filter from the left sidebar to see the item which is associated with the database. Select service-based database, give it a name and click on add.

Step 8

Now we create a table that we user in login and registration. Double click on the database file from solution explorer. It will open a database file in the server explorer.

Expand your database and right-click on the table, then click on Add New Table.

Step 9

Create a table field that you want. Here, I added only three fields, ID, Username, and password, where ID is auto incremented by 1. You can set it by right clicking on the field name, click on property, and find the Id Identity Specification. Expand it and make it true (Is Identity) field and give an increment number which increments Id by adding this number in the last Id.

q

CREATE TABLE [dbo].[LoginTable]  
(  
    [Id] INT NOT NULL PRIMARY KEY IDENTITY,   
    [username] NVARCHAR(50) NULL,   
    [password] NVARCHAR(50) NULL  
) 

Step 10

Now we create a Registration form. Create a design for your form as you need. In the below image, you see how I design a form.

Step 11

Now click anywhere on the form. It will generate a Form_Load event where you can enter the following code. This code creates a database connection and opens it. In the next step, you will learn how you get that connection string which are added in SQLConnection Constructor.

private void Registration_Load(object sender, EventArgs e)  
{  
    cn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=H:\Website\RegistrationAndLogin\Database.mdf;Integrated Security=True");  
    cn.Open();  
}

Step 12

Go to Server Explorer, right-click on the database, then click on Modify Connection.

Step 13

Now you see a windows dialog popup click on the advance button. This will open another dialog. Before that, click on the test button and check that your database is working properly.

Step 14

Copy the path which shows below on this dialog and close both dialogs. Then paste this path in the form load event. Add @ sign before this path so there’s no need to change the slash.

Step 15

We need to open the login page when the user clicks on the login button, so enter the following code in the Login Button click event. 

private void Button1_Click(object sender, EventArgs e)  
{  
    this.Hide();  
    Login login = new Login();  
    login.ShowDialog();
}

Code Explanation

1. First, we hide the current form which is registration .
2. Then we create an object of login page and show login form using that object.

Step 16

Now add the following code in the registration button click event: 

private void BtnRegister_Click(object sender, EventArgs e)  
{  
    if (txtconfirmpassword.Text != string.Empty || txtpassword.Text != string.Empty || txtusername.Text != string.Empty)  
    {  
        if (txtpassword.Text == txtconfirmpassword.Text)  
        {  
            cmd = new SqlCommand("select * from LoginTable where username='" + txtusername.Text + "'", cn);  
            dr = cmd.ExecuteReader();  
            if (dr.Read())  
            {  
                dr.Close();  
                MessageBox.Show("Username Already exist please try another ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
            }  
            else  
            {  
                dr.Close();  
                cmd = new SqlCommand("insert into LoginTable values(@username,@password)", cn);  
                cmd.Parameters.AddWithValue("username", txtusername.Text);  
                cmd.Parameters.AddWithValue("password", txtpassword.Text);  
                cmd.ExecuteNonQuery();  
                MessageBox.Show("Your Account is created . Please login now.", "Done", MessageBoxButtons.OK, MessageBoxIcon.Information);  
            }  
        }  
        else  
        {  
            MessageBox.Show("Please enter both password same ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
        }  
    }  
    else  
    {  
        MessageBox.Show("Please enter value in all field.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
    }  
}

Code Explanation

1. First of all, we check that the user entered a value in all fields. If yes, then continue, otherwise, show a message using the message box.
2. Then we check if the password and confirm password both are the same.
3. Then we check if any record/user is already registered with that username if not then continue further otherwise show an error message.
4. In last we insert data in the table using the SQLCommand object.

Step 17

Now we create a login page. Here, I added two text boxes for username and password and two buttons for a login and open registration form.

Step 18

Click on anywhere in a form which generates a Form_Load event add connection code, as shown below.

private void Login_Load(object sender, EventArgs e)  
{  
    cn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=H:\Website\RegistrationAndLogin\Database.mdf;Integrated Security=True");  
    cn.Open();  
}

Step 19

On a Registration button click, add the following code which opens the registration form.

private void Btnregister_Click(object sender, EventArgs e)  
{  
    this.Hide();  
    Registration registration = new Registration();  
    registration.ShowDialog();  
}

Step 20

Add the below code in the login button click for redirecting users to the home page form if the user exists.

private void BtnLogin_Click(object sender, EventArgs e)  
{  
    if (txtpassword.Text != string.Empty || txtusername.Text != string.Empty)  
    {  
  
        cmd = new SqlCommand("select * from LoginTable where username='" + txtusername.Text + "' and password='"+txtpassword.Text+"'", cn);  
        dr = cmd.ExecuteReader();  
        if (dr.Read())  
        {  
            dr.Close();  
            this.Hide();  
            Home home = new Home();  
            home.ShowDialog();  
        }  
        else  
        {  
            dr.Close();  
            MessageBox.Show("No Account avilable with this username and password ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
        }  
  
    }  
    else  
    {  
        MessageBox.Show("Please enter value in all field.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
    }  
}

Code Explanation

1. Here, first of all, we check if the user enters a value in both fields. If yes, then continue, otherwise, show an error message.
2. Then we check if the user exists in our database with that username and password. If the user exists, then open the home page which we generated at the start.

Step 21

Change the start page as login in Program.cs File.

static void Main()
{
    Application.EnableVisualStyles();  
    Application.SetCompatibleTextRenderingDefault(false);  
    Application.Run(new Login());  
}

Step 22

Now run your application.

Login.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RegistrationAndLogin
{
    public partial class Login : Form
    {
        SqlCommand cmd;
        SqlConnection cn;
        SqlDataReader dr;

        public Login()
        {
            InitializeComponent();
        }

        private void Login_Load(object sender, EventArgs e)
        {
            cn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=D:\Articles\Code\RegistrationAndLogin\Database.mdf;Integrated Security=True");
            cn.Open();
        }

        private void Btnregister_Click(object sender, EventArgs e)
        {
            this.Hide();
            Registration registration = new Registration();
            registration.ShowDialog();
        }

        private void BtnLogin_Click(object sender, EventArgs e)
        {
            if (txtpassword.Text != string.Empty || txtusername.Text != string.Empty)
            {

                cmd = new SqlCommand("select * from LoginTable where username='" + txtusername.Text + "' and password='"+txtpassword.Text+"'", cn);
                dr = cmd.ExecuteReader();
                if (dr.Read())
                {
                    dr.Close();
                    this.Hide();
                    Home home = new Home();
                    home.ShowDialog();
                }
                else
                {
                    dr.Close();
                    MessageBox.Show("No Account avilable with this username and password ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }

            }
            else
            {
                MessageBox.Show("Please enter value in all field.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

    }
}

Registration.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RegistrationAndLogin
{
    public partial class Registration : Form
    {

        SqlCommand cmd;
        SqlConnection cn;
        SqlDataReader dr;

        public Registration()
        {
            InitializeComponent();
        }

        private void Registration_Load(object sender, EventArgs e)
        {
            cn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=D:\Articles\Code\RegistrationAndLogin\Database.mdf;Integrated Security=True");
            cn.Open();
        }

        private void BtnRegister_Click(object sender, EventArgs e)
        {
            if (txtconfirmpassword.Text != string.Empty || txtpassword.Text != string.Empty || txtusername.Text != string.Empty)
            {
                if (txtpassword.Text == txtconfirmpassword.Text)
                {
                    cmd = new SqlCommand("select * from LoginTable where username='" + txtusername.Text + "'", cn);
                    dr = cmd.ExecuteReader();
                    if (dr.Read())
                    {
                        dr.Close();
                        MessageBox.Show("Username Already exist please try another ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    else
                    {
                        dr.Close();
                        cmd = new SqlCommand("insert into LoginTable values(@username,@password)", cn);
                        cmd.Parameters.AddWithValue("username", txtusername.Text);
                        cmd.Parameters.AddWithValue("password", txtpassword.Text);
                        cmd.ExecuteNonQuery();
                        MessageBox.Show("Your Account is created . Please login now.", "Done", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
                else
                {
                    MessageBox.Show("Please enter both password same ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            else
            {
                MessageBox.Show("Please enter value in all field.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void Button1_Click(object sender, EventArgs e)
        {
            this.Hide();
            Login login = new Login();
            login.ShowDialog();
        }
    }
}

Home.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RegistrationAndLogin
{
    public partial class Home : Form
    {
        public Home()
        {
            InitializeComponent();
        }
    }
}

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RegistrationAndLogin
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Login());
        }
    }
}

Conclusion

So here, we created a simple login and registration page in a Windows Form application. I hope you liked this article, share it with your friends.