窗体-异步执行进度

前些天由于匆忙，因此只贴了代码，现在把它补全。

窗体界面如下图：

窗体属性：

　　FormBorderStyle：None

　　ShowInTaskbar：false

ProgressBar属性：

　　Name：progressBar

代码部分：

using System;
using System.Drawing;
using System.Windows.Forms;

using System.Threading;

namespace BaseAssembly
{
    public delegate void ChangeValue(int value);
    public delegate void CloseForm();

    public partial class Form_Loading : Form
    {

        #region Fields

        private WaitCallback runMethod; //要执行的委托
        private object state;           //作为RunMethod的参数传递
        private Form callForm;          //调用窗体

        #endregion Fields


        #region Properties

        /// <summary>
        /// 异步执行的方法。
        /// 请在执行的最后使用Invoke调用窗体的Close方法以关闭窗体
        /// </summary>
        public WaitCallback RunMethod
        {
            get { return this.runMethod; }
            set { this.runMethod = value; }
        }

        /// <summary>
        /// 作为RunMethod的参数传递
        /// </summary>
        public object State
        {
            get { return this.state; }
            set { this.state = value; }
        }

        #endregion Properties


        //Constructor
        public Form_Loading(Form callForm)
        {
            this.callForm = callForm;
            InitializeComponent();
        }

        /// <summary>
        /// 进度最大值
        /// 在异步方法中请使用Invoke调用该方法以更新值
        /// </summary>
        /// <param name="value">最大值</param>
        public void SetProgressBarMaximum(int value)
        {
            this.progressBar.Maximum = value;
        }

        /// <summary>
        /// 设置进度栏的当前值
        /// 在异步方法中请使用Invoke调用该方法以更新值
        /// </summary>
        /// <param name="value">值</param>
        public void SetProgressBarValue(int value)
        {
            if (value > this.progressBar.Maximum)
                this.progressBar.Value = this.progressBar.Maximum;
            this.progressBar.Value = value;
        }

        protected override void OnVisibleChanged(EventArgs e)
        {
            //只在显示时执行
            if (this.Visible && RunMethod != null)
            {
                //设置起始位置
                this.StartPosition = FormStartPosition.Manual;
                this.Location = new Point(
                    this.callForm.Location.X + (this.callForm.Width - this.Width) / 2,
                    this.callForm.Location.Y + (this.callForm.Height - this.Height) / 2);
                //执行异步命令
                //Thread thRunMethod = new Thread(new ParameterizedThreadStart(this.RunMethod));
                //thRunMethod.Start(this.State);
                ThreadPool.QueueUserWorkItem(this.RunMethod);
                base.OnVisibleChanged(e);
            }
        }

        protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData == (Keys)(262144 + 115)) //Alt-F4
            {
                return true;
            }
            return base.ProcessCmdKey(ref msg, keyData);
        }
    }
}