My Code

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 DukeIsabellaMacDonald
{
    public partial class SignIn : Form
    {
        public SignIn()
        {
            InitializeComponent();
        }

        private void label4_Click(object sender, EventArgs e)
        {
            private static string SignInUsername = "";
        public static string SignInPassword = "";
        String username = "Luna101";
        private TextBox Username;
        private TextBox Password;
        private PictureBox pictureBox1;
        private Label label1;
        private Label label2;
        private Button Exit;
        private Button Loggin;
        String password = "Kat46"; //username and password will change to the users username and password.

        public static void Main()
        {
            double Username, Password;

            try
            {
                Username = double.Parse(UsernameTextbox.Text);
                Password = double.Parse(PasswordTextBox.Text);
            }
            catch
            {
                MessageBox.Show("Please Enter Password");
                PasswordTextBox.Focus();
                PasswordTextBox.SelectAll();

            }
            catch
            {
                MessageBox.Show("Invalid Username or Password. Please Try Again");
                PasswordTextBox.Focus();
                UsernameTextBox.Focus();
                PasswordTextBox.SelectAll();
                UsernameTextBox.Selectall();
            }
            private void InitializeComponent()
            {
                System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(SignIn));
                this.Username = new System.Windows.Forms.TextBox();
                this.Password = new System.Windows.Forms.TextBox();
                this.pictureBox1 = new System.Windows.Forms.PictureBox();
                this.label1 = new System.Windows.Forms.Label();
                this.Password = new System.Windows.Forms.Label();
                this.Exit = new System.Windows.Forms.Button();
                this.Loggin = new System.Windows.Forms.Button();
                ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
                this.SuspendLayout();
                //
                // textBox1
                //
                this.Username.Location = new System.Drawing.Point(269, 157);
                this.Username.Name = "textBox1";
                this.Username.Size = new System.Drawing.Size(197, 26);
                this.Username.TabIndex = 0;
                //
                // textBox2
                //
                this.Password.Location = new System.Drawing.Point(269, 61);
                this.Password.Name = "textBox2";
                this.Password.Size = new System.Drawing.Size(197, 26);
                this.Password.TabIndex = 1;
                //
                // pictureBox1
                //
                this.pictureBox1.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image")));
                this.pictureBox1.Location = new System.Drawing.Point(269, 247);
                this.pictureBox1.Name = "pictureBox1";
                this.pictureBox1.Size = new System.Drawing.Size(313, 168);
                this.pictureBox1.TabIndex = 2;
                this.pictureBox1.TabStop = false;
                //
                // label1
                //
                this.label1.AutoSize = true;
                this.label1.Location = new System.Drawing.Point(124, 61);
                this.label1.Name = "label1";
                this.label1.Size = new System.Drawing.Size(87, 20);
                this.label1.TabIndex = 3;
                this.label1.Text = "Username:";
                //
                // label2
                //
                this.Password.AutoSize = true;
                this.Password.Location = new System.Drawing.Point(124, 157);
                this.Password.Name = "label2";
                this.Password.Size = new System.Drawing.Size(82, 20);
                this.Password.TabIndex = 4;
                this.Password.Text = "Password:";
                //
                // button1
                //
                this.Exit.Location = new System.Drawing.Point(661, 61);
                this.Exit.Name = "button1";
                this.Exit.Size = new System.Drawing.Size(99, 50);
                this.Exit.TabIndex = 5;
                this.Exit.Text = "Exit";
                this.Exit.UseVisualStyleBackColor = true;
                //
                // button2
                //
                this.Loggin.Location = new System.Drawing.Point(661, 157);
                this.Loggin.Name = "button2";
                this.Loggin.Size = new System.Drawing.Size(99, 53);
                this.Loggin.TabIndex = 6;
                this.Loggin.Text = "Loggin";
                this.Loggin.UseVisualStyleBackColor = true;
                //
                // SignIn
                //
                this.ClientSize = new System.Drawing.Size(883, 427);
                this.Controls.Add(this.Loggin);
                this.Controls.Add(this.Exit);
                this.Controls.Add(this.Password);
                this.Controls.Add(this.label1);
                this.Controls.Add(this.pictureBox1);
                this.Controls.Add(this.Password);
                this.Controls.Add(this.Username);
                this.Name = "SignIn";
                this.Text = "Sign In";
                ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
                ResumeLayout(false);
                PerformLayout();

            }
        }
    }
}