How to Create Login Window in C# using SQL Server Database in Visual Studio?

1. Open your visual studio of any version and then go to file new and then click on project. Then new window will appear and from the left pane select visual c#. under visual c# select window and then select window form application from the middle pane and give the name of your project and click ok.

2. Drag and drop two label, two textbox and one button from the toolbox and change the text and name of these control from the properties of these controls.

3. Now from the left pane select server explorer and right click on data connection and click on add connection. After clicking on add connection new window will appear and you will see the Data Source option and Database file name (new or existing); set the Data Source to Microsoft SQL Server Database File(SqlClient ) and give any name in the database file name section and then click ok, new window will appear as below:

Then click yes, after clicking yes, server explorer will look like the following one:

4. Then right click on table>Add new Table, add username and password in the name section and choose the data type and then click on the update icon.

you can also change the name of the table from the SQL Command shown just below the this table and then you should click on update button.

5. Now select you database in my case testlogin.mdf from the server explorer and go to properties, from the properties window copy the connection string.

6. Now you need to add one namespace as:

using System.Data.sqlclient;

7. Then go to the design section of the login window and double click on the button and write following code inside that button.

Note: change the connection string and SQL Statement (Table name and database name) based on your specification.

SqlConnection conn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\RANBAH~1\Documents\testlogin.mdf;Integrated Security=True;Connect Timeout=30");
            SqlDataAdapter sda = new SqlDataAdapter("select count(*) from login where username ='" + textBox1.Text + "' and password='" + textBox2.Text + "'", conn);
            DataTable dt = new DataTable();
            sda.Fill(dt);
            if (dt.Rows[0][0].ToString() == "1")
            {
                this.Hide();
                Main mm = new Main();
                mm.Show();
            }
            else
            {
                MessageBox.Show("please enter correct username and password", "alert", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }