Login/Registration Page

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;
using System.Media;
using System.Data.SqlClient;

namespace AlexandriasBibliothek
{
    public partial class Form1 : Form
    {
        private bool check_name = false;
        private bool check_nachname = false;
        private bool check_user_id = false;
        private bool check_password = false;
        private bool check_birthday = false;

        public Form1()
        {
            InitializeComponent();

            SoundPlayer StartUp = new SoundPlayer(@"C:\Alexandria\Sound\320664_pizzaiolo_lovelyboot1.wav");
            StartUp.Play();

            textBox2.Enabled = false;

            textBox3.ForeColor = System.Drawing.Color.Gray;
            textBox4.ForeColor = System.Drawing.Color.Gray;
            textBox5.ForeColor = System.Drawing.Color.Gray;
            textBox6.ForeColor = System.Drawing.Color.Gray;
            textBox7.ForeColor = System.Drawing.Color.Gray;
            textBox8.ForeColor = System.Drawing.Color.Gray;
            textBox9.ForeColor = System.Drawing.Color.Gray;
            textBox10.ForeColor = System.Drawing.Color.Gray;

            dateTimePicker1.CalendarForeColor = System.Drawing.Color.Gray;

            textBox2.UseSystemPasswordChar = true;

            checkBox1.Enabled = false;
            checkBox2.Enabled = false;
            checkBox3.Enabled = false;
            checkBox4.Enabled = false;
            checkBox5.Enabled = false;
            checkBox6.Enabled = false;
            checkBox7.Enabled = false;
            checkBox8.Enabled = false;
            checkBox9.Enabled = false;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (textBox1.Text != "") { textBox2.Enabled = true; checkBox5.Enabled = true; }
            else { textBox2.Enabled = false; checkBox5.Enabled = false; }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                if (textBox1.Text != "" && textBox2.Text != "")
                {
                    try
                    {
                        using (SqlConnection conn = new SqlConnection())
                        {
                            conn.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Alexandria\Database\Database1.mdf;Integrated Security=True;";
                            conn.Open();            //Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Alexandria\Database\Database1.mdf;Integrated Security=True

                            SqlCommand SelectCommand = new SqlCommand("SELECT * FROM USERS WHERE @0 = user_id and @1 = user_password;", conn);

                            SelectCommand.Parameters.Add(new SqlParameter("@0", textBox1.Text));
                            SelectCommand.Parameters.Add(new SqlParameter("@1", textBox2.Text));

                            if (SelectCommand.ExecuteNonQuery() > 0)
                            {
                                MessageBox.Show("Welcome, " + textBox1.Text);

                                /*Form2 scd_screen = new Form2();
                                scd_screen.Location = this.Location;
                                scd_screen.Size = this.Size;
                                scd_screen.Show();
                                this.Hide();*/
                            }
                            else { MessageBox.Show("Wrong UserID or password!"); }
                        }
                    }
                    catch { MessageBox.Show("Wrong UserID or password!"); }
                }
                else { MessageBox.Show("Wrong UserID or password!"); }
            }
            catch { MessageBox.Show("Wrong UserID or password!"); }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (check_name == true && check_nachname == true && check_user_id == true && check_password == true && check_birthday)
            {
                int plz = 0;
                int.TryParse(textBox6.Text, out plz);

                using (SqlConnection conn = new SqlConnection())
                {
                    try
                    {
                        conn.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Alexandria\Database\Database1.mdf;Integrated Security=True;";
                        conn.Open();            //Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Alexandria\Database\Database1.mdf;Integrated Security=True

                        SqlCommand insertCommand = new SqlCommand("Insert into USERS values(@a,@b,@c,@d,@e,@f,@g,@h,@i);", conn);

                        insertCommand.Parameters.Add(new SqlParameter("@a", textBox5.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@b", textBox4.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@c", textBox3.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@d", dateTimePicker1.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@e", textBox10.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@f", textBox7.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@g", plz));
                        insertCommand.Parameters.Add(new SqlParameter("@h", textBox9.Text));
                        insertCommand.Parameters.Add(new SqlParameter("@i", textBox8.Text));

                        if (insertCommand.ExecuteNonQuery() == 1)
                        {
                            MessageBox.Show("Welcome, " + textBox3.Text + " " + textBox4.Text);

                            /*Form2 scd_screen = new Form2();
                            scd_screen.Location = this.Location;
                            scd_screen.Size = this.Size;
                            scd_screen.Show();
                            this.Hide();*/
                        }
                    }
                    catch
                    {
                        MessageBox.Show(textBox5.Text + " has alredy been taken. Sorry");

                        textBox5.ForeColor = System.Drawing.Color.Gray;
                        textBox5.Text = "UserID";
                    }
                }
            }
            else
            {
                if (check_name != true) MessageBox.Show("Please enter a valid name");
                if (check_nachname != true) MessageBox.Show("Please enter a valid surname");
                if (check_user_id != true) MessageBox.Show("Please enter a valid UserID");
                if (check_password != true) MessageBox.Show("Please enter a valid password");
                if (check_birthday != true) MessageBox.Show("Please enter a valid birthday");
            }
        }

        private void checkBox5_CheckedChanged(object sender, EventArgs e)
        {
            if (checkBox5.Checked == true)
            {
                textBox2.UseSystemPasswordChar = false;
            }
            else textBox2.UseSystemPasswordChar = true;
        }

        private void checkBox6_CheckedChanged(object sender, EventArgs e)
        {
            if (textBox10.ForeColor == System.Drawing.Color.Black && checkBox6.Checked == false)
            {
                textBox10.UseSystemPasswordChar = true;
            }
            else if (textBox10.ForeColor == System.Drawing.Color.Gray || checkBox6.Checked == true)
            {
                textBox10.UseSystemPasswordChar = false;
            }
        }

        private void textBox3_Enter(object sender, EventArgs e)
        {
            if(textBox3.ForeColor == System.Drawing.Color.Gray)
            {
                textBox3.ForeColor = System.Drawing.Color.Black;
                textBox3.Text = "";
            }
        }

        private void textBox3_Leave(object sender, EventArgs e)
        {
            if (textBox3.Text == "")
            {
                textBox3.ForeColor = System.Drawing.Color.Gray;
                textBox3.Text = "Name";
            }
            else check_name = true;
        }

        private void textBox4_Enter(object sender, EventArgs e)
        {
            if (textBox4.ForeColor == System.Drawing.Color.Gray)
            {
                textBox4.ForeColor = System.Drawing.Color.Black;
                textBox4.Text = "";
            }
        }

        private void textBox4_Leave(object sender, EventArgs e)
        {
            if (textBox4.Text == "")
            {
                textBox4.ForeColor = System.Drawing.Color.Gray;
                textBox4.Text = "Surname";
            }
            else check_nachname = true;
        }

        private void textBox5_Enter(object sender, EventArgs e)
        {
            if (textBox5.ForeColor == System.Drawing.Color.Gray)
            {
                textBox5.ForeColor = System.Drawing.Color.Black;
                textBox5.Text = "";
            }
        }

        private void textBox5_Leave(object sender, EventArgs e)
        {
            if (textBox5.Text == "")
            {
                textBox5.ForeColor = System.Drawing.Color.Gray;
                textBox5.Text = "UserID";
            }
        }

        private void textBox6_Enter(object sender, EventArgs e)
        {
            if (textBox6.ForeColor == System.Drawing.Color.Gray)
            {
                textBox6.ForeColor = System.Drawing.Color.Black;
                textBox6.Text = "";
            }
        }

        private void textBox6_Leave(object sender, EventArgs e)
        {
            if (textBox6.Text == "")
            {
                textBox6.ForeColor = System.Drawing.Color.Gray;
                textBox6.Text = "ZIP";
            }
        }

        private void textBox7_Enter(object sender, EventArgs e)
        {
            if (textBox7.ForeColor == System.Drawing.Color.Gray)
            {
                textBox7.ForeColor = System.Drawing.Color.Black;
                textBox7.Text = "";
            }
        }

        private void textBox7_Leave(object sender, EventArgs e)
        {
            if (textBox7.Text == "")
            {
                textBox7.ForeColor = System.Drawing.Color.Gray;
                textBox7.Text = "Town";
            }
        }

        private void textBox8_Enter(object sender, EventArgs e)
        {
            if (textBox8.ForeColor == System.Drawing.Color.Gray)
            {
                textBox8.ForeColor = System.Drawing.Color.Black;
                textBox8.Text = "";
            }
        }

        private void textBox8_Leave(object sender, EventArgs e)
        {
            if (textBox8.Text == "")
            {
                textBox8.ForeColor = System.Drawing.Color.Gray;
                textBox8.Text = "Street";
            }
        }

        private void textBox9_Enter(object sender, EventArgs e)
        {
            if (textBox9.ForeColor == System.Drawing.Color.Gray)
            {
                textBox9.ForeColor = System.Drawing.Color.Black;
                textBox9.Text = "";
            }
        }

        private void textBox9_Leave(object sender, EventArgs e)
        {
            if (textBox9.Text == "")
            {
                textBox9.ForeColor = System.Drawing.Color.Gray;
                textBox9.Text = "Housenumber";
            }
        }

        private void textBox10_Enter(object sender, EventArgs e)
        {
            if (textBox10.ForeColor == System.Drawing.Color.Gray)
            {
                textBox10.ForeColor = System.Drawing.Color.Black;
                textBox10.Text = "";
            }
        }

        private void textBox10_Leave(object sender, EventArgs e)
        {
            if (textBox10.Text == "")
            {
                textBox10.ForeColor = System.Drawing.Color.Gray;
                textBox10.Text = "Password";
            }
        }

        private void dateTimePicker1_Enter(object sender, EventArgs e)
        {

        }

        private void dateTimePicker1_Leave(object sender, EventArgs e)
        {

        }

        private void textBox10_TextChanged(object sender, EventArgs e)
        {
            if (textBox10.Text == "")
            {
                checkBox1.Checked = false;
                checkBox2.Checked = false;
                checkBox3.Checked = false;
                checkBox4.Checked = false;
                checkBox7.Checked = false;
            }

            if (textBox10.ForeColor == System.Drawing.Color.Black && checkBox6.Checked == false)
            {
                textBox10.UseSystemPasswordChar = true;
            }
            else if (textBox10.ForeColor == System.Drawing.Color.Gray || checkBox6.Checked == true)
            {
                textBox10.UseSystemPasswordChar = false;
            }

            if (textBox10.Text != "" && textBox10.Text != "Password")
            {
                checkBox6.Enabled = true;

                int pass_length = textBox10.Text.Length;

                int a = 0, b = 0, c = 0, d = 0, f = 0;

                for (int i = 0; i < pass_length; i++)
                {
                    if (pass_length >= 8)
                    {
                        checkBox7.Checked = true;
                    }
                    else if (pass_length < 8) checkBox7.Checked = false;

                    if (Char.IsUpper(textBox10.Text[i]))
                    {
                        checkBox1.Checked = true;
                        b = i;
                    }
                    else if(Char.IsUpper(textBox10.Text[b]) != true) checkBox1.Checked = false;

                    if (Char.IsLower(textBox10.Text[i]))
                    {
                        checkBox2.Checked = true;
                        c = i;
                    }
                    else if (Char.IsLower(textBox10.Text[c]) != true) checkBox2.Checked = false;

                    if (int.TryParse(Convert.ToString(textBox10.Text[i]), out a))
                    {
                        checkBox3.Checked = true;
                        d = i;
                    }
                    else if (int.TryParse(Convert.ToString(textBox10.Text[d]), out a) != true) checkBox3.Checked = false;

                    if ((textBox10.Text[i]>32) && (textBox10.Text[i]<48))
                    {
                        checkBox4.Checked = true;
                        f = i;
                    }
                    else if ((textBox10.Text[f] > 32) && (textBox10.Text[f] < 48) != true) checkBox4.Checked = false;

                    if (checkBox1.Checked == true && checkBox2.Checked == true && checkBox3.Checked == true && checkBox4.Checked == true && checkBox7.Checked == true)
                    {
                        check_password = true;
                    }
                    else { check_password = false; }
                }
            }
            else { checkBox6.Enabled = false; }
        }

        private void textBox5_TextChanged(object sender, EventArgs e)
        {
            int check_length = textBox5.Text.Length;

            if (check_length >= 6 && check_length <= 20)
            {
                checkBox8.Checked = true;
                check_user_id = true;
            }
            else { checkBox8.Checked = false; check_user_id = false; }
        }

        private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
        {
            DateTime current_time = DateTime.Now;
            DateTime picked_time = Convert.ToDateTime(dateTimePicker1.Text);

            int value = DateTime.Compare(current_time, picked_time);

            if (value > 0) { checkBox9.Checked = true; check_birthday = true; }
            else { checkBox9.Checked = false; check_birthday = false; }
        }

        private void groupBox2_Enter(object sender, EventArgs e)
        {

        }
    }
}