C# WinForm 滚动条换肤

时间:2023-01-27 08:47:01
滚动条换肤是C#WinForm中的难点,因为很多控件的滚动条是由系统来进行绘制的,所以滚动条的绘制就不得不使用大量的API函数来进行绘制。如果对API函数不熟悉的话,就很难达到自己想要的效果,而这部分本身就不是C#的强项,所以网上使用C++重绘滚动条的例子很多,但用C#写的确很少。

       在看过这篇文章后,如果您有什么好的意见和建议,请在下面留言。

       先看一下效果图:

C# WinForm 滚动条换肤

 

     上图实现的是一个仿FoxMail的换肤控件的截图,其中实现了TreeView、Panel、DataGridView和ListBox的滚动条的换肤,下面介绍一下滚动条换肤的原来。

      在网上搜了一下,滚动条换肤一般有两种方法实现。第一种方式比较变态,直接拦截系统绘制滚动条的消息,将绘制过程接管过来,这种方式显然不是C#的强项,不过网上已经有了C++的实现版本,如果对C++比较熟悉的话,可以研究一下,如果哪位用空改成C#的版本,希望可以给我发一份。

      C++版本的滚动条换肤示例代码下载:/Files/liutao409/SkinSB.rar(这个例子实现的效果相当的不错,并且没有什么Bug,很值得研究一下)

C# WinForm 滚动条换肤

     第二种方法相对来说比较简单,就是将自己绘制的滚动条覆盖在控件的滚动条上面,然后让自己绘制的滚动条和控件自身的滚动条进行联动就可以了。关于如何自绘滚动条,网上应该可以找得到,我这里就不详细说了,只提供一个滚动条绘制的源代码给大家下载。

     C#版自绘垂直滚动条示例代码下载:/Files/liutao409/customscrollbar_src.rar

     上面介绍了滚动条绘制需要处理的一些问题,下面的就是本文的重点,如何让自定义滚动条和控件的滚动条进行联动。下面我用DataGridview的滚动条的例子来说明。

     其它地方我就不多说了,代码里面写得很明白,关键的水平和垂直滚动条的相关参数的说明给大家讲解一下,这个参数的算法绝对是原创,并且可以跟系统自带的滚动条高度的同步:

 

    this._hScrollBarEx.Maximum = 需要滚动的区域的宽度;(包括显示区域和未显示的滚动区域的宽度,注意不包括行标题列)

    this._hScrollBarEx.LargeChange = _hScrollBarEx.Maximum / _hScrollBarEx.Width +显示区域的宽度(可显示的区域的宽度,注意不包括行标题列);

    this._vScrollBarEx.Maximum = 显示区域包含的数据的行数 + _vScrollBarEx.Minimum + _vScrollBarEx.LargeChange(默认值为100) - 1;

 

public classDataGridViewEx : DataGridView

    {  

        private int _displayRowCount = 0;

        private int _displayWidth = 0;

        private ScrollBarEx.HScrollBarEx _hScrollBarEx;

        private ScrollBarEx.VScrollBarEx _vScrollBarEx;

        public DataGridViewEx():base()

        {

            _hScrollBarEx = new HScrollBarEx();

            _vScrollBarEx = new VScrollBarEx();

            this.Controls.Add(_hScrollBarEx);

            this.Controls.Add(_vScrollBarEx);

            base.SetStyle(ControlStyles.UserPaint |ControlStyles.AllPaintingInWmPaint |ControlStyles.OptimizedDoubleBuffer,true);

            this.HorizontalScrollBar.VisibleChanged +=new EventHandler(ScrollBar_VisibleChanged);

            this.VerticalScrollBar.VisibleChanged +=new EventHandler(ScrollBar_VisibleChanged);

            this.SizeChanged += new EventHandler(ScrollBar_VisibleChanged);

            this._vScrollBarEx.ValueChanged +=new EventHandler(VScrollBarEx_ValueChanged);

            this._hScrollBarEx.ValueChanged +=new EventHandler(HScrollBarEx_ValueChanged);

            this.Scroll += new ScrollEventHandler(DataGridViewEx_Scroll);

            this.ColumnHeadersHeightChanged +=new EventHandler(ScrollBar_VisibleChanged);

            this.ColumnWidthChanged +=new DataGridViewColumnEventHandler(ScrollBar_VisibleChanged);

            this.RowHeadersWidthChanged +=new EventHandler(ScrollBar_VisibleChanged);

            this.RowHeightChanged +=new DataGridViewRowEventHandler(ScrollBar_VisibleChanged);

            this.RowsAdded += new DataGridViewRowsAddedEventHandler(ScrollBar_VisibleChanged);

            this.RowsRemoved += new DataGridViewRowsRemovedEventHandler(ScrollBar_VisibleChanged);

            this.ColumnAdded += new DataGridViewColumnEventHandler(ScrollBar_VisibleChanged);

            this.ColumnRemoved +=new DataGridViewColumnEventHandler(ScrollBar_VisibleChanged);

            this.DataSourceChanged +=new EventHandler(ScrollBar_VisibleChanged);

            SetScrollBarEx();

        }

 

        private void VScrollBarEx_ValueChanged(object sender,EventArgs e)

        {

            if (!this.dgvScroll)

            {

                this.FirstDisplayedScrollingRowIndex = _vScrollBarEx.Value;

                Application.DoEvents();

            }

        }

 

        private void HScrollBarEx_ValueChanged(object sender,EventArgs e)

        {

            if (!this.dgvScroll)

            {

                this.HorizontalScrollingOffset = _hScrollBarEx.Value;

                GetDisplayWidth();

                Application.DoEvents();

            }

        }

 

        private void DataGridViewEx_Scroll(object sender, ScrollEventArgs e)

        {

            this.dgvScroll = true;

            if (e.ScrollOrientation ==ScrollOrientation.VerticalScroll)

            {

                _vScrollBarEx.Value = this.FirstDisplayedScrollingRowIndex;

            }

            else

            {

                _hScrollBarEx.Value = this.HorizontalScrollingOffset;

            }

            this.dgvScroll = false;

        }

 

        private void ScrollBar_VisibleChanged(object sender,EventArgs e)

        {

            SetScrollBarEx();

        }

 

        private void SetScrollBarEx()

        {

            if (this.VerticalScrollBar.Visible)

            {

                _vScrollBarEx.Visible = true;

                _vScrollBarEx.Location = new Point(this.DisplayRectangle.Width, 0);

                this.VerticalScrollBar.SendToBack();

                _vScrollBarEx.Height = this.DisplayRectangle.Height;

 

                GetDisplayRowCount();

            }

            else

            {

                _vScrollBarEx.Visible = false;

            }

 

            if (this.HorizontalScrollBar.Visible)

            {

               _hScrollBarEx.Visible = true;

                _hScrollBarEx.Location = new Point(0, this.DisplayRectangle.Height);

                this.HorizontalScrollBar.SendToBack();

                _hScrollBarEx.Width = this.DisplayRectangle.Width ;

 

                GetDisplayWidth();

                _hScrollBarEx.Value = this.HorizontalScrollingOffset;

            }

            else

            {

                _hScrollBarEx.Visible = false;

            }

        }

 

        public int GetDisplayWidth()

        {

            int width = 0;

            for (int i = 0; i <this.Columns.Count; i++)

            {

                width += this.Columns[i].Width;

            }

            _displayWidth = width;

            this._hScrollBarEx.Maximum = width;

            this._hScrollBarEx.LargeChange = _hScrollBarEx.Maximum / _hScrollBarEx.Width +this.DisplayRectangle.Width - this.RowHeadersWidth;

            return width;

        }

 

        public int GetDisplayRowCount()

        {

            int j = 0;

           int height = 0;

            int i = this.FirstDisplayedScrollingRowIndex;

            if (i < 0)

            {

                i = 0;

            }

            for (; i < this.Rows.Count; i++)

            {

                height += this.Rows[i].Height;

                if (height < this.DisplayRectangle.Height - this.ColumnHeadersHeight)

                {

                    j++;

                }

                else

                {

                    break;

                }

 

            }

            j = this.Rows.Count - j;

            if (j < 0)

            {

                j = 0;

            }

            if (_displayRowCount != j)

            {

                _displayRowCount = j;

                _vScrollBarEx.Maximum = j + _vScrollBarEx.Minimum + _vScrollBarEx.LargeChange - 1;

                if (this.FirstDisplayedScrollingRowIndex < 0)

                {

                    _vScrollBarEx.Value = 0;

                }

                else if (this.FirstDisplayedScrollingRowIndex > _vScrollBarEx.Maximum)

                {

                    _vScrollBarEx.Value = _vScrollBarEx.Maximum;

                }

                else

                {

                    _vScrollBarEx.Value = this.FirstDisplayedScrollingRowIndex;

                }

            }

            return j;

        }

   }

      DataGridview的滚动条不是由系统进行绘制的,所以滚动条的很多参数都是可以取到的,但是像Listbox或者Textbox这样的控件,滚动条的信息很多都不好获取,这个时候,就要使用API函数来进行处理了,但整个滚动条的覆盖方案还是可以参照上面的来进行,只是把一些参数的获取和设置改由API函数来完成就行了,当然在一些细节的地方会有所不同。

      关于滚动条的API函数的说明,可以参考这一篇博客:http://www.cnblogs.com/yellowyu/archive/2009/02/15/1390926.html

特别要注意的是下面两句:

      我原来以为只要用SetScrollInfo设置控件的滚动条参数后控件就会自动滚动到指定的位置,但实际结果却不是这样的,必须还要调用PostMessage发送一个让控件滚动的消息控件才会滚动。

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

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