Winform 启动时的渐入渐出效果

两个form：
    frmLogo，logo窗口，启动时渐入渐出。
    MainForm，程序的主窗口。

frmLogo.Designer.cs 部分代码

//frmLogo.Designer.cs 部分代码

namespace FormTransparentEffectAtStart_up
{
        //省略部分不重要的代码

      /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.label1 = new System.Windows.Forms.Label();
            this.timer1 = new System.Windows.Forms.Timer(this.components);
            this.SuspendLayout();
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.BackColor = System.Drawing.Color.Silver;
            this.label1.Font = new System.Drawing.Font("华文新魏", 15F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
            this.label1.ForeColor = System.Drawing.Color.Black;
            this.label1.Location = new System.Drawing.Point(70, 47);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(297, 21);
            this.label1.TabIndex = 0;
            this.label1.Text = "FormTransparentEffectAtStart-up";
            // 
            // timer1
            // 
            this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
            // 
            // FrmLogo
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.BackColor = System.Drawing.Color.FromArgb(((int)(((byte)(0)))), ((int)(((byte)(0)))), ((int)(((byte)(192)))));
            this.ClientSize = new System.Drawing.Size(438, 114);
            this.Controls.Add(this.label1);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            this.Name = "FrmLogo";
            this.Opacity = 0;
            this.ShowIcon = false;
            this.ShowInTaskbar = false;
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "FrmLogo";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Timer timer1;
    }
}

//frmLogo.cs 代码

//frmLogo.cs 代码

namespace FormTransparentEffectAtStart_up
{
    public partial class FrmLogo : Form
    {
        public FrmLogo()
        {
            InitializeComponent();

            this.Opacity = 0;//透明度 设置为0

            this.timer1.Enabled = true;
            this.timer1.Interval = 150;//触发时间为150ms
        }

        bool bSubtractAlpha = true;//减少透明度
        bool bAddAlpha = false;//增加透明度

        private void timer1_Tick(object sender, EventArgs e)
        {
            
            //逐渐减少透明度
            if (bSubtractAlpha)
            {
                if (this.Opacity < 1)
                {
                    this.Opacity += 0.1;
                }
                else
                {
                    bSubtractAlpha = false;
                    bAddAlpha = true;
                }
            }

            //逐渐增加透明度
            if (bAddAlpha)
            {
                if (this.Opacity > 0.1)
                {
                    this.Opacity -= 0.1;
                }
                else
                {
                    bAddAlpha = false;
                    this.timer1.Enabled = false;
                }
            }

            //启动主窗口
            if (this.timer1.Enabled == false)
            {
                new MainForm().Show();
            }

        }
    }
}

//MainForm.cs 代码

//MainForm.cs 代码
namespace FormTransparentEffectAtStart_up
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            //关闭所有
            Application.ExitThread();
        }
    }
}