simple login fcode for C#

step1;
1st u have to open the visual studio .net . and then select language for c#.press ok.
step2:
form opened.and select tools->Datatable ->create table->
step3:
or copy and paste the code for login.aspx.
public string GetConnectionString()
    {
        returnSystem.Configuration.ConfigurationManager.ConnectionStrings["ur database name"].ConnectionString;    }






step4:

private void execution(string name, string username, string password, string emailid)
    {
        SqlConnection con = new SqlConnection(GetConnectionString());
        string sql = "INSERT INTO urtablename (name, username, password, emailid) VALUES "        + " (@name, @username, @password, @emailid)";
        try        {
            con.Open();
            
            SqlCommand cmd = new SqlCommand(sql, conn);
            SqlParameter[] pram = new SqlParameter[4];

            param[0] = new SqlParameter("@name", SqlDbType.VarChar, 50);
            param[1] = new SqlParameter("@username", SqlDbType.VarChar, 50);
            param[2] = new SqlParameter("@password", SqlDbType.VarChar, 50);
            param[3] = new SqlParameter("@emailid", SqlDbType.Char, 10);

            param[0].Value = name;
            param[1].Value = username;
            param[2].Value = password;
            param[3].Value = emailid;

            for (int i = 0; i < pram.Length; i++)
            {
                cmd.Parameters.Add(param.[i]);
            }
            cmd.CommandType = CommandType.Text;
            cmd.ExecuteQuery();
        }
        catch ()
        {

            Exception (ex,connection);
            string msg = "Error occured while inserting";
            msg += ex_msg.Message;
            throw new Exception(msg);
        }
        finally        {
            conn.Close();

            cmd.close();

        }    }

step4:

protected void create_Click(object sender, EventArgs e)
    {
        SqlDataSource sds = new SqlDataSource();
        sql.ConnectionString =ConfigurationManager.ConnectionStrings["Ur second DBname"].ToString();

        sql.SelectParameters.Add("name", TypeCode.String, this.name.Text);
        sql.SelectParameters.Add("username", TypeCode.String, this.username.Text);
        sql.SelectParameters.Add("password", TypeCode.String, this.password.Text);
        sql.SelectParameters.Add("emailid", TypeCode.String, this.emailid.Text);

        sql.SelectCommand = "SELECT * FROM [myTb] WHERE [username] = @username";

        DataView dv = (DataView)sds.Select(DataSourceSelectArguments.Empty);

        if (dv.Count != 0)
        {
            this.lblinfo.ForeColor = System.Drawing.Color.green;
            this.lblinfo.Text

            Messagebox.show("this user already exist"); 

            return;
        }
        else        {   
            execution(name.Text,username.Text,password.Text,emailid.Text);
            this.lblinfo.Text = "New User Profile has been created you can login now";this.name.Text ="";
            this.username.Text = "";
            this.password.Text = "";
            this.emailid.Text = "";
        }    }

step5:

protected void log_Click(object sender, EventArgs e)
    {
        SqlDataSource sds = new SqlDataSource();
        sql.ConnectionString =ConfigurationManager.ConnectionStrings["myDbConnectionString1"].ToString();

        sql.SelectParameters.Add("username", TypeCode.String, this.username.Text);
        sql.SelectParameters.Add("password", TypeCode.String, this.password.Text);

        sql.SelectCommand = "SELECT * FROM [urtablename] WHERE [username] = @username AND [password] = @password";

        DataView dv = (DataView)sds.Select(DataSourceSelectArguments.Empty);

        if (dv.Count == 0)
        {
            this.lblinfo.ForeColor = System.Drawing.Color.Red;
            this.lblinfo.Text;

            MessageBox.Show("invalid username password");
            return;
        }
        else        {
            this.Session["username"] = dv[0].Row["username"].ToString();
            Response.Redirect("securepage/SecurePage.aspx");
        }    }

BASICS:

how to create table in sql DB:

Create table student(name "VARCHAR",rno INTEGER,dept "VARCHAR")

how to sho created table:

DESC table 

add value into table:

INSERT into student Value("asd",78,"cse")