c# 自定义滑块TrackBar

辛苦半天做出来的，如果觉得好用，记得点赞

效果图如下：

具体操作：

1 、添加代码（代码在下面），重新生成下整个工程，在工具栏中就出现控件，将控件拖到窗体中

2、只需要调整这些参数就行

3. 常用事件

4. 下面是代码，直接复制，将顶部 namespace 名改成你的工程名称就能用了。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 视频下载和播放
{
    public class LTrackBar : Control
    {
        public LTrackBar()
        {
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            CreateControl();
        }


        [Category("DemoUI"), Description("背景条颜色")]

        /// <summary>
        /// 未滑按钮
        /// </summary>
        private Color _BarButtonColor = Color.FromArgb(0, 0, 200); // 浅绿色
        public Color L_BarButtonColor
        {
            get { return _BarButtonColor; }
            set
            {
                _BarButtonColor = value;
                Invalidate();
            }
        }

        /// <summary>
        /// 未滑过的区域颜色
        /// </summary>
        private Color _BarColor = Color.FromArgb(128, 255, 128); // 浅绿色
        public Color L_BarColor
        {
            get { return _BarColor; }
            set{
                _BarColor = value;
                Invalidate();
            }
        }

        /// <summary>
        /// 已滑过的区域颜色
        /// </summary>
        private Color _SliderColor = Color.FromArgb(0, 200, 0); // 浅绿色
        public Color L_SliderColor
        {
            get { return _SliderColor; }
            set
            {
                _SliderColor = value;
                Invalidate();
            }
        }

        /// <summary>
        /// 圆角
        /// </summary>
        private bool _IsRound = true;
        public bool L_IsRound 
        {
            get { return _IsRound; }
            set {
                _IsRound = value;
                Invalidate();
            }
        }

        /// <summary>
        /// 最小值
        /// </summary>
        private int _Minimum = 0;
        public int L_Minimum {
            get { return _Minimum; }
            set {
                _Minimum = Convert.ToInt32(value);
                if (_Minimum >= _Maximum) { _Minimum = _Maximum - 1; }
                if (_Minimum < 0) { _Minimum = 0; }
                if (_Value < _Minimum) { _Value = _Minimum; }
                Invalidate();
            }
        }

        /// <summary>
        /// 最大值
        /// </summary>
        private int _Maximum = 100;
        public int L_Maximum
        {
            get { return _Maximum; }
            set
            {
                _Maximum = Convert.ToInt32(value);
                if (_Minimum >= _Maximum) { _Maximum = _Minimum + 1; }
                if (_Value > _Minimum) { _Value = _Minimum; }
                Invalidate();
            }
        }

        /// <summary>
        /// 添加 滑块值改变 委托事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        public delegate void LValueChangedEventHandler(object sender, LEventArgs e);
        public event LValueChangedEventHandler LValueChanged;

        /// <summary>
        /// 滑块的当前值
        /// </summary>
        private int _Value = 0;
        public int L_Value {
            get { return _Value; }
            set {
                _Value = value;
                if (_Value > _Maximum) { _Value = _Maximum; }
                if (_Value < _Minimum) { _Value = _Minimum; }
                Invalidate();
                LValueChanged?.Invoke(this, new LEventArgs(_Value));
            }
        }

        /// <summary>
        /// 滑块的方向
        /// </summary>
        private Orientation _Orientation = Orientation.Horizontal_LR;
        public Orientation L_Orientation
        {
            get { return _Orientation; }
            set {
                Orientation old = _Orientation;
                _Orientation = value;

                if (old != _Orientation)
                {
                    Size = new Size(Size.Height, Size.Width);
                }
            }            
        }

        /// <summary>
        /// 滑块的高度
        /// </summary>
        private int _BarSize = 10;
        public int L_BarSize
        {
            get { return _BarSize; }
            set
            {
                _BarSize = value;
                if (_BarSize < 3) _BarSize = 3;
                if (_Orientation == Orientation.Horizontal_LR)
                {
                    Size = new Size(Width , _BarSize);
                }
                else
                { 
                    Size = new Size(_BarSize,Height);
                }
            }
        }

        /// <summary>
        /// 实现只能调整宽度/高度，需要重写SetBoundsCore方法
        /// </summary>
        protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
        {
            if (_Orientation == Orientation.Horizontal_LR)
                base.SetBoundsCore(x, y, width, _BarSize, specified);
            else
                base.SetBoundsCore(x, y, _BarSize, height, specified);
        }

        MouseStatus mouseStatus;
        private PointF mousePoint;
        
        /// <summary>
        /// 尺寸变化是刷新
        /// </summary>
        /// <param name="e"></param>
        protected override void OnSizeChanged(EventArgs e)
        {
            base.OnSizeChanged(e);
            Invalidate();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            pValueToPoint();
            e.Graphics.SmoothingMode = SmoothingMode.HighQuality;

            float barSizeRatio = 0.7f;
            if (_BarSize < 15)
                barSizeRatio = 0.5f;

            Pen penBarBack = new Pen(_BarColor, _BarSize * barSizeRatio);
            Pen penBarFore = new Pen(_SliderColor, _BarSize * barSizeRatio);

            float fCapWidth = _BarSize;
            float fCapHalfWidth = _BarSize / 2.0f;
            if (_IsRound)
            {      
                penBarBack.StartCap = LineCap.Round;
                penBarBack.EndCap = LineCap.Round;
                penBarFore.StartCap = LineCap.Round;
                penBarFore.EndCap = LineCap.Round;
            }

            float fPointValue = 0;
            if (_Orientation == Orientation.Horizontal_LR)
            {
                e.Graphics.DrawLine(penBarBack, fCapHalfWidth, Height / 2f, Width - fCapHalfWidth, Height / 2f);

                fPointValue = mousePoint.X;
                if (fPointValue < fCapHalfWidth) fPointValue = fCapHalfWidth;
                if (fPointValue > Width - fCapHalfWidth) fPointValue = Width - fCapHalfWidth;
            }
            else
            {
                e.Graphics.DrawLine(penBarBack, Width / 2f, fCapHalfWidth, Width / 2f, Height - fCapHalfWidth);

                fPointValue = mousePoint.Y;
                if (fPointValue < fCapHalfWidth) fPointValue = fCapHalfWidth;
                if (fPointValue > Height - fCapHalfWidth) fPointValue = Height - fCapHalfWidth;
            }

            Brush brush = new SolidBrush(_BarButtonColor);
            if (_Orientation == Orientation.Horizontal_LR)
            {
                e.Graphics.DrawLine(penBarFore, fCapHalfWidth, Height / 2f, fPointValue, Height / 2f);
                e.Graphics.FillEllipse(brush, fPointValue - fCapHalfWidth, Height / 2f - fCapHalfWidth, fCapWidth-1, fCapWidth-1);
            }
            else
            {
                e.Graphics.DrawLine(penBarFore, Width / 2f, fPointValue, Width / 2f, Height - fCapHalfWidth);
                e.Graphics.FillEllipse(brush, Width / 2f - fCapHalfWidth, fPointValue - fCapHalfWidth, fCapWidth-1, fCapWidth - 1);
            }
        }

        private void pValueToPoint()
        {
            float fCapWidth = _BarSize;
            float fCapHalfWidth = _BarSize / 2.0f;

            float fRatio = Convert.ToSingle(_Value - _Minimum) / (_Maximum - _Minimum);
            if (_Orientation == Orientation.Horizontal_LR)
            {
                float fPointValue = fRatio * (Width - fCapWidth) + fCapHalfWidth;
                mousePoint = new PointF(fPointValue, fCapHalfWidth);
            }
            else
            {
                float fPointValue = Height - fCapHalfWidth - fRatio * (Height - fCapWidth);
                mousePoint = new PointF(fCapHalfWidth, fPointValue);
            }
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            mouseStatus = MouseStatus.Down;
            mousePoint = e.Location;
            pPointToValue();
            Invalidate();
            base.OnMouseDown(e);     
        }
        
        protected override void OnMouseUp(MouseEventArgs e)
        {
            mouseStatus = MouseStatus.Up;
            base.OnMouseUp(e); 
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            if (mouseStatus == MouseStatus.Down)
            {
                mousePoint = e.Location;
                pPointToValue();
                Invalidate();
            }
            base.OnMouseMove(e);
        }

        protected override void OnMouseEnter(EventArgs e)
        {
            mouseStatus = MouseStatus.Enter;
            base.OnMouseEnter(e);    
        }

        protected override void OnMouseLeave(EventArgs e)
        {           
            mouseStatus = MouseStatus.Leave;
            base.OnMouseLeave(e);
        }

        /// <summary>
        /// 计算滑块位置
        /// </summary>
        private void pPointToValue()
        {
            float fCapHalfWidth = 0;
            float fCapWidth = 0;

            if (_IsRound)
            {
                fCapWidth = _BarSize;
                fCapHalfWidth = _BarSize * 0.5f;
            }

            // 计算滑块的位置
            if (_Orientation == Orientation.Horizontal_LR)
            {
                float fRatio = Convert.ToSingle(mousePoint.X - fCapHalfWidth) / (Width - fCapWidth);
                _Value = Convert.ToInt32(fRatio * (_Maximum - _Minimum) + _Minimum);
            }
            else
            {
                float fRatio = Convert.ToSingle(Height - mousePoint.Y - fCapHalfWidth) / (Height - fCapWidth);
                _Value = Convert.ToInt32(fRatio * (_Maximum - _Minimum) + _Minimum);
            }

            if (_Value < _Minimum)
                _Value = _Minimum;
            else if (_Value > _Maximum)
                _Value = _Maximum;

            LValueChanged?.Invoke(this, new LEventArgs(_Value));
        }
    }

    public class LEventArgs : EventArgs
    {
        public LEventArgs(object value)
        {
            Value = value;
        }
    
        public object Value { get; set; }
    }




    /// <summary>
    /// 控件方向
    /// </summary>
    public enum Orientation
    { 
        /// <summary>
        /// 水平方向 （从左到右）
        /// </summary>
        Horizontal_LR,
        / <summary>
        / 水平方向 （从右到左）
        / </summary>
        //Horizontal_RL,
        /// <summary>
        /// 垂直方向 （从下到上）
        /// </summary>
        Vertical_BT,
        / <summary>
        /  垂直方向 （从上到下）
        / </summary>
        //Vertical_TB,
    }

    /// <summary>
    /// 鼠标状态
    /// </summary>
    public enum MouseStatus
    { 
        /// <summary>
        /// 鼠标进入
        /// </summary>
        Enter,
        /// <summary>
        /// 鼠标离开
        /// </summary>
        Leave,
        /// <summary>
        /// 鼠标按下
        /// </summary>
        Down,
        /// <summary>
        /// 鼠标放开
        /// </summary>
        Up
    }

}