C#平滑进度条

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;

namespace SmoothProgressBar
{
    public partial class SmoothProgressBar : UserControl
    {
        int min = 0;    // Minimum value for progress range
        int max = 100;    // Maximum value for progress range
        int val = 0;        // Current progress

        Color BarColor = Color.FromArgb(87, 148, 249);        // Color of progress meter

        /**//// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /**//// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        组件设计器生成的代码#region 组件设计器生成的代码

        /**//// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.panel1 = new System.Windows.Forms.Panel();
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // panel1
            // 
            this.panel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.panel1.Location = new System.Drawing.Point(16, 11);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(261, 14);
            this.panel1.TabIndex = 0;
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(283, 13);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(17, 12);
            this.label1.TabIndex = 1;
            this.label1.Text = "0%";
            // 
            // SmoothProgressBar
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.Controls.Add(this.label1);
            this.Controls.Add(this.panel1);
            this.Name = "SmoothProgressBar";
            this.Size = new System.Drawing.Size(316, 39);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.Label label1;


        //
        public SmoothProgressBar()
        {
            InitializeComponent();
            this.panel1.Paint += new PaintEventHandler(panel1_Paint);
            this.panel1.Resize += new EventHandler(panel1_Resize);
        }

        void panel1_Resize(object sender, EventArgs e)
        {
            //throw new Exception("The method or operation is not implemented.");
            this.panel1.Invalidate();
        }

        void panel1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            SolidBrush brush = new SolidBrush(BarColor);
            float percent = (float)(val - min) / (float)(max - min);
            Rectangle rect = this.panel1.ClientRectangle;

            // Calculate area for drawing the progress.
            rect.Width = (int)((float)rect.Width * percent);

            // Draw the progress meter.
            g.FillRectangle(brush, rect);

            // Draw a three-dimensional border around the control.
            Draw3DBorder(g);

            // Clean up.
            brush.Dispose();
            g.Dispose();
        }

        public int Minimum
        {
            get
            {
                return min;
            }

            set
            {
                // Prevent a negative value.
                if (value < 0)
                {
                    min = 0;
                }

                // Make sure that the minimum value is never set higher than the maximum value.
                if (value > max)
                {
                    min = value;
                    min = value;
                }

                // Ensure value is still in range
                if (val < min)
                {
                    val = min;
                }

                // Invalidate the control to get a repaint.
                this.panel1.Invalidate();
            }
        }

        public int Maximum
        {
            get
            {
                return max;
            }

            set
            {
                // Make sure that the maximum value is never set lower than the minimum value.
                if (value < min)
                {
                    min = value;
                }

                max = value;

                // Make sure that value is still in range.
                if (val > max)
                {
                    val = max;
                }

                // Invalidate the control to get a repaint.
                this.panel1.Invalidate();              
            }
        }

        public int Value
        {
            get
            {
                return val;
            }

            set
            {
                int oldValue = val;

                // Make sure that the value does not stray outside the valid range.
                if (value < min)
                {
                    val = min;
                    this.label1.Text = "0%";
                }
                else if (value > max)
                {
                    val = max;
                    this.label1.Text = "100%";
                }
                else
                {
                    val = value;
                    double d_val =Convert.ToDouble( val * 100 / max);
                    
                    this.label1.Text = Convert.ToDouble(Math.Round(d_val)).ToString() + "%";
                }

                // Invalidate only the changed area.
                float percent;

                Rectangle newValueRect = this.panel1.ClientRectangle; //this.ClientRectangle;
                Rectangle oldValueRect = this.panel1.ClientRectangle;//this.ClientRectangle;

                // Use a new value to calculate the rectangle for progress.
                percent = (float)(val - min) / (float)(max - min);
                newValueRect.Width = (int)((float)newValueRect.Width * percent);

                // Use an old value to calculate the rectangle for progress.
                percent = (float)(oldValue - min) / (float)(max - min);
                oldValueRect.Width = (int)((float)oldValueRect.Width * percent);

                Rectangle updateRect = new Rectangle();

                // Find only the part of the screen that must be updated.
                if (newValueRect.Width > oldValueRect.Width)
                {
                    updateRect.X = oldValueRect.Size.Width;
                    updateRect.Width = newValueRect.Width - oldValueRect.Width;
                }
                else
                {
                    updateRect.X = newValueRect.Size.Width;
                    updateRect.Width = oldValueRect.Width - newValueRect.Width;
                }

                updateRect.Height = this.panel1.Height;

                // Invalidate the intersection region only.
                this.panel1.Invalidate(updateRect);
            }
        }

        public Color ProgressBarColor
        {
            get
            {
                return BarColor;
            }

            set
            {
                BarColor = value;

                // Invalidate the control to get a repaint.
                this.panel1.Invalidate();
            }
        }

        private void Draw3DBorder(Graphics g)
        {
            int PenWidth = (int)Pens.White.Width;
            Rectangle clientRect = this.panel1.ClientRectangle;

            g.DrawLine(Pens.DarkGray,
                new Point(clientRect.Left, clientRect.Top),
                new Point(clientRect.Width - PenWidth, clientRect.Top));
            g.DrawLine(Pens.DarkGray,
                new Point(clientRect.Left, clientRect.Top),
                new Point(clientRect.Left, clientRect.Height - PenWidth));
            g.DrawLine(Pens.White,
                new Point(clientRect.Left, clientRect.Height - PenWidth),
                new Point(clientRect.Width - PenWidth, clientRect.Height - PenWidth));
            g.DrawLine(Pens.White,
                new Point(clientRect.Width - PenWidth, clientRect.Top),
                new Point(clientRect.Width - PenWidth, clientRect.Height - PenWidth));
        }
    }
}

效果图：