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用重绘的滚动条控制ListBox的滚动

时间：2009/4/7 8:37:00来源：本站整理作者：我要评论(1)

查了很多资料,都找不到直接重写ListBox滚动条的方法,只能曲线救国,先自己重绘一个带皮肤的滚动条,然后让它取代ListBox现有的滚动条.
老习惯，先传个效果图，你觉得感兴趣就继续看下去，不喜欢的话就此打住，懒得耽误你宝

贵的时间，嘿嘿

注意，此图中的滚动条宽度明显小于ListBox本身滚动条的宽度，我目前只顾着实现功能了，毕竟，宽度调整相当简单哈。

下面简单介绍下重绘系统滚动条的详细步骤:

1.在项目中添加新项--用户控件,我们命名为CustomScrollbar.cs

2.准备几张图片添加进项目资源作为滚动条重绘时要用的背景,我用的图片如下:

 

     uparrow.png资源名称为uparrow   ，滚动条的上箭头
 

     ThumbBottom.png资源名称为ThumbBottom  ，滚动条中间滑道的背景
 


    ThumbMiddle.png资源名称为ThumbMiddle  ，滚动条的中间的拖动块


    downarrow.png资源名称为downarrow   ，滚动条的下箭头

 

3.然后就是利用上面图片做背景重画滚动条背景了,直接给出CustomScrollbar.cs的代码吧
Code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.Design;
using System.Diagnostics;
namespace Winamp
{
    [Designer(typeof(ScrollbarControlDesigner))]
    public partial class CustomScrollbar : UserControl
    {

        protected Color moChannelColor = Color.Empty;
        protected Image moUpArrowImage = null;//上箭头
        //protected Image moUpArrowImage_Over = null;
        //protected Image moUpArrowImage_Down = null;
        protected Image moDownArrowImage = null;//下箭头
        //protected Image moDownArrowImage_Over = null;
        //protected Image moDownArrowImage_Down = null;
        protected Image moThumbArrowImage = null;

        protected Image moThumbTopImage = null;
        protected Image moThumbTopSpanImage = null;
        protected Image moThumbBottomImage = null;
        protected Image moThumbBottomSpanImage = null;
        protected Image moThumbMiddleImage = null;

        protected int moLargeChange = 10;
        protected int moSmallChange = 1;
        protected int moMinimum = 0;
        protected int moMaximum = 100;
        protected int moValue = 0;
        private int nClickPoint;

        protected int moThumbTop = 0;

        protected bool moAutoSize = false;

        private bool moThumbDown = false;
        private bool moThumbDragging = false;

        public new event EventHandler Scroll = null;
        public event EventHandler ValueChanged = null;

        private int GetThumbHeight()
        {
            int nTrackHeight = (this.Height - (UpArrowImage.Height + DownArrowImage.Height));
            float fThumbHeight = ((float)LargeChange / (float)Maximum) * nTrackHeight;
            int nThumbHeight = (int)fThumbHeight;

            if (nThumbHeight > nTrackHeight)
            {
                nThumbHeight = nTrackHeight;
                fThumbHeight = nTrackHeight;
            }
            if (nThumbHeight < 56)
            {
                nThumbHeight = 56;
                fThumbHeight = 56;
            }

            return nThumbHeight;
        }

        public CustomScrollbar()
        {

            InitializeComponent();
            SetStyle(ControlStyles.ResizeRedraw, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.DoubleBuffer, true);

            moChannelColor = Color.FromArgb(51, 166, 3);
            UpArrowImage = BASSSkin.uparrow;//上箭头
            DownArrowImage = BASSSkin.downarrow;//下肩头


            ThumbBottomImage = BASSSkin.ThumbBottom;

            ThumbMiddleImage = BASSSkin.ThumbMiddle;

            this.Width = UpArrowImage.Width;//18px
            base.MinimumSize = new Size(UpArrowImage.Width, UpArrowImage.Height + DownArrowImage.Height + GetThumbHeight());
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Behavior"), Description("LargeChange")]
        public int LargeChange
        {
            get { return moLargeChange; }
            set
            {
                moLargeChange = value;
                Invalidate();
            }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Behavior"), Description("SmallChange")]
        public int SmallChange
        {
            get { return moSmallChange; }
            set
            {
                moSmallChange = value;
                Invalidate();
            }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Behavior"), Description("Minimum")]
        public int Minimum
        {
            get { return moMinimum; }
            set
            {
                moMinimum = value;
                Invalidate();
            }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Behavior"), Description("Maximum")]
        public int Maximum
        {
            get { return moMaximum; }
            set
            {
                moMaximum = value;
                Invalidate();
            }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Behavior"), Description("Value")]
        public int Value
        {
            get { return moValue; }
            set
            {
                moValue = value;

                int nTrackHeight = (this.Height - (UpArrowImage.Height + DownArrowImage.Height));
                float fThumbHeight = ((float)LargeChange / (float)Maximum) * nTrackHeight;
                int nThumbHeight = (int)fThumbHeight;

                if (nThumbHeight > nTrackHeight)
                {
                    nThumbHeight = nTrackHeight;
                    fThumbHeight = nTrackHeight;
                }
                if (nThumbHeight < 56)
                {
                    nThumbHeight = 56;
                    fThumbHeight = 56;
                }

                //figure out value
                int nPixelRange = nTrackHeight - nThumbHeight;
                int nRealRange = (Maximum - Minimum) - LargeChange;
                float fPerc = 0.0f;
                if (nRealRange != 0)
                {
                    fPerc = (float)moValue / (float)nRealRange;

                }

                float fTop = fPerc * nPixelRange;
                moThumbTop = (int)fTop;


                Invalidate();
            }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Skin"), Description("Channel Color")]
        public Color ChannelColor
        {
            get { return moChannelColor; }
            set { moChannelColor = value; }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Skin"), Description("Up Arrow Graphic")]
        public Image UpArrowImage
        {
            get { return moUpArrowImage; }
            set { moUpArrowImage = value; }
        }

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Skin"), Description("Up Arrow Graphic")]
        public Image DownArrowImage
        {
            get { return moDownArrowImage; }
            set { moDownArrowImage = value; }
        }


        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Skin"), Description("Up Arrow Graphic")]
        public Image ThumbBottomImage
        {
            get { return moThumbBottomImage; }
            set { moThumbBottomImage = value; }
        }

 

        [EditorBrowsable(EditorBrowsableState.Always), Browsable(true), DefaultValue(false), Category("Skin"), Description("Up Arrow Graphic")]
        public Image ThumbMiddleImage
        {
            get { return moThumbMiddleImage; }
            set { moThumbMiddleImage = value; }
        }

        protected override void OnPaint(PaintEventArgs e)
        {

            e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;

            if (UpArrowImage != null)
            {
                e.Graphics.DrawImage(UpArrowImage, new Rectangle(new Point(0, 0), new Size(this.Width, UpArrowImage.Height)));
            }

            Brush oBrush = new SolidBrush(moChannelColor);
            Brush oWhiteBrush = new SolidBrush(Color.FromArgb(255, 255, 255));
            //          函数名: rectangle
            //功 能: 画一个矩形
            //用 法: void far rectangle(int left, int top, int right, int bottom);

            //draw channel left and right border colors
            e.Graphics.FillRectangle(oWhiteBrush, new Rectangle(0, UpArrowImage.Height, 1, (this.Height - DownArrowImage.Height)));
            e.Graphics.FillRectangle(oWhiteBrush, new Rectangle(this.Width - 1, UpArrowImage.Height, 1, (this.Height - DownArrowImage.Height)));

            //draw channel
            //e.Graphics.FillRectangle(oBrush, new Rectangle(1, UpArrowImage.Height, this.Width-2, (this.Height-DownArrowImage.Height)));
            e.Graphics.DrawImage(ThumbBottomImage, new Rectangle(0, UpArrowImage.Height, this.Width, (this.Height - DownArrowImage.Height)));
            //draw thumb
            int nTrackHeight = (this.Height - (UpArrowImage.Height + DownArrowImage.Height));
            float fThumbHeight = ((float)LargeChange / (float)Maximum) * nTrackHeight;
            int nThumbHeight = (int)fThumbHeight;

            if (nThumbHeight > nTrackHeight)
            {
                nThumbHeight = nTrackHeight;
                fThumbHeight = nTrackHeight;
            }
            //MessageBox.Show(nThumbHeight.ToString());
            if (nThumbHeight < 56)
            {
                nThumbHeight = 56;
                fThumbHeight = 56;
            }

            //Debug.WriteLine(nThumbHeight.ToString());

            //float fSpanHeight = (fThumbHeight - (ThumbMiddleImage.Height + ThumbTopImage.Height + ThumbBottomImage.Height)) / 2.0f;
            //int nSpanHeight = (int)fSpanHeight;

            int nTop = moThumbTop;//0
            nTop += UpArrowImage.Height;//9px

            //draw top画上面的按钮
            //e.Graphics.DrawImage(ThumbTopImage, new Rectangle(0, nTop, this.Width, ThumbTopImage.Height));

            //nTop += ThumbTopImage.Height;//10px
            //draw top span
            //Rectangle rect = new Rectangle(1, nTop, this.Width - 2, nSpanHeight);


            //e.Graphics.DrawImage(ThumbTopSpanImage, 1.0f,(float)nTop, (float)this.Width-2.0f, (float) fSpanHeight*2);

            // nTop += nSpanHeight;//11px
            //draw middle
            e.Graphics.DrawImage(ThumbMiddleImage, new Rectangle(0, nTop, this.Width, ThumbMiddleImage.Height));


            //nTop += ThumbMiddleImage.Height;
            //draw top span
            //rect = new Rectangle(1, nTop, this.Width - 2, nSpanHeight*2);
            //e.Graphics.DrawImage(ThumbBottomSpanImage, rect);

            //nTop += nSpanHeight;
            //draw bottom
            //e.Graphics.DrawImage(ThumbBottomImage, new Rectangle(1, nTop, this.Width - 2, nSpanHeight));

            if (DownArrowImage != null)
            {
                e.Graphics.DrawImage(DownArrowImage, new Rectangle(new Point(0, (this.Height - DownArrowImage.Height)), new Size(this.Width, DownArrowImage.Height)));
            }

        }


        public override bool AutoSize
        {
            get
            {
                return base.AutoSize;
            }
            set
            {
                base.AutoSize = value;
                if (base.AutoSize)
                {
                    this.Width = moUpArrowImage.Width;
                }
            }
        }

        private void InitializeComponent()
        {
            this.SuspendLayout();
            //
            // CustomScrollbar
            //
            this.Name = "CustomScrollbar";
            this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.CustomScrollbar_MouseDown);
            this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.CustomScrollbar_MouseMove);
            this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.CustomScrollbar_MouseUp);
            this.ResumeLayout(false);

        }

        private void CustomScrollbar_MouseDown(object sender, MouseEventArgs e)
        {
            Point ptPoint = this.PointToClient(Cursor.Position);
            int nTrackHeight = (this.Height - (UpArrowImage.Height + DownArrowImage.Height));
            float fThumbHeight = ((float)LargeChange / (float)Maximum) * nTrackHeight;
            int nThumbHeight = (int)fThumbHeight;

            if (nThumbHeight > nTrackHeight)
            {
                nThumbHeight = nTrackHeight;
                fThumbHeight = nTrackHeight;
            }
            if (nThumbHeight < 56)
            {
                nThumbHeight = 56;
                fThumbHeight = 56;
            }

            int nTop = moThumbTop;
            nTop += UpArrowImage.Height;


            Rectangle thumbrect = new Rectangle(new Point(1, nTop), new Size(ThumbMiddleImage.Width, nThumbHeight));
            if (thumbrect.Contains(ptPoint))
            {

                //hit the thumb
                nClickPoint = (ptPoint.Y - nTop);
                //MessageBox.Show(Convert.ToString((ptPoint.Y - nTop)));
                this.moThumbDown = true;
            }

            Rectangle uparrowrect = new Rectangle(new Point(1, 0), new Size(UpArrowImage.Width, UpArrowImage.Height));
            if (uparrowrect.Contains(ptPoint))
            {

                int nRealRange = (Maximum - Minimum) - LargeChange;
                int nPixelRange = (nTrackHeight - nThumbHeight);
                if (nRealRange > 0)
                {
                    if (nPixelRange > 0)
                    {
                        if ((moThumbTop - SmallChange) < 0)
                            moThumbTop = 0;
                        else
                            moThumbTop -= SmallChange;

                        //figure out value
                        float fPerc = (float)moThumbTop / (float)nPixelRange;
                        float fValue = fPerc * (Maximum - LargeChange);

                        moValue = (int)fValue;
                        Debug.WriteLine(moValue.ToString());

                        if (ValueChanged != null)
                            ValueChanged(this, new EventArgs());

                        if (Scroll != null)
                            Scroll(this, new EventArgs());

                        Invalidate();
                    }
                }
            }

            Rectangle downarrowrect = new Rectangle(new Point(1, UpArrowImage.Height + nTrackHeight), new Size(UpArrowImage.Width, UpArrowImage.Height));
            if (downarrowrect.Contains(ptPoint))
            {
                int nRealRange = (Maximum - Minimum) - LargeChange;
                int nPixelRange = (nTrackHeight - nThumbHeight);
                if (nRealRange > 0)
                {
                    if (nPixelRange > 0)
                    {
                        if ((moThumbTop + SmallChange) > nPixelRange)
                            moThumbTop = nPixelRange;
                        else
                            moThumbTop += SmallChange;

                        //figure out value
                        float fPerc = (float)moThumbTop / (float)nPixelRange;
                        float fValue = fPerc * (Maximum - LargeChange);

                        moValue = (int)fValue;
                        Debug.WriteLine(moValue.ToString());

                        if (ValueChanged != null)
                            ValueChanged(this, new EventArgs());          if (Scroll != null)
                            Scroll(this, new EventArgs());

 

                        Invalidate();
                    }
                }
            }
        }

        private void CustomScrollbar_MouseUp(object sender, MouseEventArgs e)
        {
            this.moThumbDown = false;
            this.moThumbDragging = false;
        }

        private void MoveThumb(int y)
        {
            int nRealRange = Maximum - Minimum;
            int nTrackHeight = (this.Height - (UpArrowImage.Height + DownArrowImage.Height));
            float fThumbHeight = ((float)LargeChange / (float)Maximum) * nTrackHeight;
            int nThumbHeight = (int)fThumbHeight;

            if (nThumbHeight > nTrackHeight)
            {
                nThumbHeight = nTrackHeight;
                fThumbHeight = nTrackHeight;
            }
            if (nThumbHeight < 56)
            {
                nThumbHeight = 56;
                fThumbHeight = 56;
            }

            int nSpot = nClickPoint;

            int nPixelRange = (nTrackHeight - nThumbHeight);
            if (moThumbDown && nRealRange > 0)
            {
                if (nPixelRange > 0)
                {
                    int nNewThumbTop = y - (UpArrowImage.Height + nSpot);

                    if (nNewThumbTop < 0)
                    {
                        moThumbTop = nNewThumbTop = 0;
                    }
                    else if (nNewThumbTop > nPixelRange)
                    {
                        moThumbTop = nNewThumbTop = nPixelRange;
                    }
                    else
                    {
                        moThumbTop = y - (UpArrowImage.Height + nSpot);
                    }

                    //figure out value
                    float fPerc = (float)moThumbTop / (float)nPixelRange;
                    float fValue = fPerc * (Maximum - LargeChange);
                    moValue = (int)fValue;
                    Debug.WriteLine(moValue.ToString());

                    Application.DoEvents();

                    Invalidate();
                }
            }
        }

        private void CustomScrollbar_MouseMove(object sender, MouseEventArgs e)
        {
            if (moThumbDown == true)
            {
                this.moThumbDragging = true;
            }

            if (this.moThumbDragging)
            {

                MoveThumb(e.Y);
            }

            if (ValueChanged != null)
                ValueChanged(this, new EventArgs());

            if (Scroll != null)
                Scroll(this, new EventArgs());
        }

    }

    internal class ScrollbarControlDesigner : System.Windows.Forms.Design.ControlDesigner
    {

 

        public override SelectionRules SelectionRules
        {
            get
            {
                SelectionRules selectionRules = base.SelectionRules;
                PropertyDescriptor propDescriptor = TypeDescriptor.GetProperties(this.Component)["AutoSize"];
                if (propDescriptor != null)
                {
                    bool autoSize = (bool)propDescriptor.GetValue(this.Component);
                    if (autoSize)
                    {
                        selectionRules = SelectionRules.Visible | SelectionRules.Moveable | SelectionRules.BottomSizeable | SelectionRules.TopSizeable;
                    }
                    else
                    {
                        selectionRules = SelectionRules.Visible | SelectionRules.AllSizeable | SelectionRules.Moveable;
                    }
                }
                return selectionRules;
            }
        }
    }
}
目前只想简单实现滚动条中上箭头/下箭头/滑道/拖动块的重写,所以以上代码中OnPaint函数里的部分内容被我注释了,好了,这个滚动条控件已经做好了,一个控件而已，你应该会使用它，我就不罗嗦了。

接下来就是怎么用它来控制ListBox的内容滚动的问题了，这需要调用API函数来实现，同时又不能设置ListBox无滚动条，因为ListBox没有滚动条也就没有滚动的事件可捕获，那就达不到滚动的效果了。

在你的窗体里拖一个listbox控件和一个上边我们制作好的用户控件，分明命名为listBox和customScrollbar1，

然后往listBox中随便多弄写内容，使之出现滚动条即可。调整customScrollbar1的位置使之覆盖在listBox的滚动条上，呵呵，这方法不错吧？

然后我们定义一下Win32API，代码如下：

Code
public class Win32API
        {
            [StructLayout(LayoutKind.Sequential)]
            public struct tagSCROLLINFO
            {
                public uint cbSize;
                public uint fMask;
                public int nMin;
                public int nMax;
                public uint nPage;
                public int nPos;
                public int nTrackPos;
            }
            public enum fnBar
            {
                SB_HORZ = 0,
                SB_VERT = 1,
                SB_CTL = 2
            }
            public enum fMask
            {
                SIF_ALL,
                SIF_DISABLENOSCROLL = 0X0010,
                SIF_PAGE = 0X0002,
                SIF_POS = 0X0004,
                SIF_RANGE = 0X0001,
                SIF_TRACKPOS = 0X0008
            }

            public static int MakeLong(short lowPart, short highPart)
            {
                return (int)(((ushort)lowPart) | (uint)(highPart << 16));
            }
            public const int SB_THUMBTRACK = 5;
            public const int WM_HSCROLL = 0x114;
            public const int WM_VSCROLL = 0x115;
            [DllImport("user32.dll", EntryPoint = "GetScrollInfo")]
            public static extern bool GetScrollInfo(IntPtr hwnd, int fnBar, ref SCROLLINFO lpsi);
         [DllImport("user32.dll", EntryPoint = "SetScrollInfo")]
        public static extern int SetScrollInfo(IntPtr hwnd, int fnBar, [In] ref SCROLLINFO  lpsi, bool fRedraw);

        [DllImport("User32.dll", CharSet = CharSet.Auto, EntryPoint = "SendMessage")]
        static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool PostMessage(IntPtr hWnd, uint Msg, long wParam,int lParam);
        }


             
        public struct SCROLLINFO
        {
            public uint cbSize;
            public uint fMask;
            public int nMin;
            public int nMax;
            public uint nPage;
            public int nPos;
            public int nTrackPos;
        }
        enum ScrollInfoMask
        {
            SIF_RANGE = 0x1,
            SIF_PAGE = 0x2,
            SIF_POS = 0x4,
            SIF_DISABLENOSCROLL = 0x8,
            SIF_TRACKPOS = 0x10,
            SIF_ALL = SIF_RANGE + SIF_PAGE + SIF_POS + SIF_TRACKPOS
        }
         enum ScrollBarDirection
        {
            SB_HORZ = 0,
            SB_VERT = 1,
            SB_CTL = 2,
            SB_BOTH = 3
        }


        public SCROLLINFO tvImageListScrollInfo
        {

            get
            {

                SCROLLINFO si = new SCROLLINFO();

                si.cbSize = (uint)Marshal.SizeOf(si);

                si.fMask = (int)(ScrollInfoMask.SIF_DISABLENOSCROLL | ScrollInfoMask.SIF_ALL);

                Win32API.GetScrollInfo(listBox.Handle, (int)ScrollBarDirection.SB_VERT, ref si);

                return si;

            }

        }
        //当鼠标滚动时，设置该滚动条

private void SetImageListScroll()

{

SCROLLINFO info = tvImageListScrollInfo;

if (info.nMax > 0)

{

int pos = info.nPos - 1;

if (pos >= 0)

{

    customScrollbar1.Value = pos;

}

}

}
定义customScrollbar1的滚动事件函数customScrollbar1_Scroll，实现在滚动条滚动的同时发消息给listBox使之同步滚动

Code
private void customScrollbar1_Scroll(object sender, EventArgs m)
        {
            //当滚动条滚动时，通知控件也跟着滚动吧。。。

            SCROLLINFO info = tvImageListScrollInfo;

            info.nPos = customScrollbar1.Value;

            Win32API.SetScrollInfo(listBox.Handle, (int)ScrollBarDirection.SB_VERT, ref info, true);

            Win32API.PostMessage(listBox.Handle, Win32API.WM_VSCROLL, Win32API.MakeLong((short)Win32API.SB_THUMBTRACK, (short)(info.nPos)), 0);


        }

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