新表单将在后台打开

Question

我正在开发一个多表单应用程序，大约有6个表单。当我想打开另一个表单并关闭当前表单时，一切正常。我只是运行这段代码：

using System;
using System.Data.SqlClient;
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 MetroFramework.Forms;
using System.IO;
using System.Reflection;

namespace MetroLoader
{
    public partial class updater : MetroForm
    {
        int val = 0;
        bool dir = true;
        bool upd = false;

        public updater()
        {
            InitializeComponent();
            timer1.Start();
            CheckUpdate();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (val == 0)
                dir = true;
            if (val == 100)
                dir = false;
            if (dir == true)
            {
                metroProgressSpinner1.Value = val;
                val = val + 1;
            }
            else
            {
                metroProgressSpinner1.Value = val;
                val = val - 1;
            }
        }

        private void CheckUpdate()
        {
            try
            {
                SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
                builder.DataSource = "x.database.windows.net";
                builder.UserID = "x";
                builder.Password = "x";
                builder.InitialCatalog = "Sirius Accounts Database";

                using (SqlConnection connection = new SqlConnection(builder.ConnectionString))
                {
                    connection.Open();
                    StringBuilder sb = new StringBuilder();
                    sb.Append("SELECT * FROM Data WHERE lastver='1.3'");
                    String sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        SqlDataReader reader = command.ExecuteReader();

                        if (reader.HasRows)
                        {
                            upd = false;
                        }
                        else
                        {
                            upd = true;
                            this.Text = "Update available!";
                        }
                        reader.Close();
                        connection.Close();
                    }
                }
            }
            finally
            {
                if (upd == true)
                {
                    metroProgressSpinner1.Visible = false;
                    timer1.Stop();
                    timer1.Enabled = false;
                    metroButton1.Visible = true;
                    label1.Visible = true;
                }
                else
                {
                    timer1.Stop();
                    timer1.Enabled = false;
                    this.Hide();
                    var form1 = new Form1();
                    form1.Closed += (s, args) => this.Close();
                    form1.Show();
                }
            }
        }

        private void metroButton1_Click(object sender, EventArgs e)
        {
            object link = "www.google.ro";
            try
            {
                SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
                builder.DataSource = "x.database.windows.net";
                builder.UserID = "x";
                builder.Password = "x";
                builder.InitialCatalog = "Sirius Accounts Database";

                using (SqlConnection connection = new SqlConnection(builder.ConnectionString))
                {
                    connection.Open();
                    StringBuilder sb = new StringBuilder();
                    sb.Append("SELECT * FROM Data WHERE this='True'");
                    String sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        SqlDataReader reader = command.ExecuteReader();

                        while (reader.Read())
                        {
                            link = reader["downLink"];
                        }
                    }
                }
            }
            finally
            {
                System.Diagnostics.Process.Start(Convert.ToString(link));
                Application.Exit();
            }
        }
    }
}

一切都很完美。但今天，我决定改变我的主表单，即我第一次运行程序时启动的表单，然后我进入了program.cs并将其更改为新表单。完善！但现在，如果我试图关闭这个新的主要形式，并打开任何其他形式，他们只是打开这个。我很喜欢，我会关闭另一个，但如果我尝试关闭任何一个表单，整个应用程序退出。似乎其他形式以某种方式依赖于主要形式。