C# WinForm控件美化扩展系列之ListView（4）-实现所有样式的美化

先看效果:





 

.NET自带的ListView控件本身就有部分BUG，例如当设置显示模式设为Tile（平铺）样式的时候，选择不同的项，就会有些选择后的背景没有完全刷新，会留下部分聚焦框。在美化的过程中，我尽量注意了这些问题，但是也没有做过多的测试，也有可能存在一些问题，首先说一下到目前已经实现了的和没有实现的功能。

实现的功能：

1、  换边框颜色。

2、  当显示模式为Details 和 List时，间隔的项显示不同的背景色。

3、  当显示模式为Details时，对列表头的美化。

4、  各种显示样式(LargeIcon、SmallIcon、List、Tile、Details)的项选择后的背景美化。

没有实现的功能：

1、  不支持显示CheckBox。这个不是不能画出来，问题是获取不到CheckBox显示的位置，因为只有点击的是系统默认的CheckBox的位置，那个项才会被选中，自己绘制的CheckBox跟默认的的位置不对的话，点击了是没用的。所以就没有支持CheckBox。

对各个项的绘制，可以通过GetBounds方法得到图标和文本的所在位置和大小，就是没有获取CheckBox的。LargeIcon、SmallIcon、List显示样式的绘制比较容易，Details样式的绘制需要注意的FullRowSelect不同设置时背景的绘制，Tile样式的文本绘制麻烦些，需要分别计算每个SubItem的文本的位置和大小。图标的绘制在项不选中的情况下很简单，选中后要实现想系统自带的那种效果需要要到API函数：ImageList_GetIcon，具体的方法，来看看全部的绘制代码吧：

 #region Draw Methods



        internal void DrawItemInternal(DrawListViewItemEventArgs e)

        {

            if (base.View == View.Details)

            {

                return;

            }



            Graphics g = e.Graphics;

            ListViewItem item = e.Item;

            ListViewItemStates itemState = e.State;

            ImageList imageList = item.ImageList;



            e.DrawBackground();



            bool bDrawImage =

                (imageList != null) &&

                (item.ImageIndex != -1 ||

                !string.IsNullOrEmpty(item.ImageKey));

            bool bSelected =

                (itemState & ListViewItemStates.Selected) != 0;



            if (bDrawImage)

            {

                DrawImage(g, item, bSelected);

            }



            if (!string.IsNullOrEmpty(item.Text))

            {

                Rectangle textRect =

                    item.GetBounds(ItemBoundsPortion.Label);

                DrawBackground(g, e.ItemIndex, textRect, bSelected);

                DrawText(g, item, textRect, bSelected);

            }

        }



        private void DrawImage(

            Graphics g, 

            ListViewItem item, 

            bool selected)

        {

            ImageList imageList = item.ImageList;

            Size imageSize = imageList.ImageSize;

            Rectangle imageRect = item.GetBounds(ItemBoundsPortion.Icon);



            if (imageRect.Width > imageSize.Width)

            {

                imageRect.X += (imageRect.Width - imageSize.Width) / 2;

                imageRect.Width = imageSize.Width;

            }



            if (imageRect.Height > imageSize.Height)

            {

                imageRect.Y += (imageRect.Height - imageSize.Height) / 2;

                imageRect.Height = imageSize.Height;

            }



            int imageIndex =

                item.ImageIndex != -1 ?

                item.ImageIndex :

                imageList.Images.IndexOfKey(item.ImageKey);



            if (selected)

            {

                IntPtr hIcon = NativeMethods.ImageList_GetIcon(

                    imageList.Handle,

                    imageIndex,

                    (int)NativeMethods.ImageListDrawFlags.ILD_SELECTED);

                g.DrawIcon(Icon.FromHandle(hIcon), imageRect);

                NativeMethods.DestroyIcon(hIcon);

            }

            else

            {

                Image image = imageList.Images[imageIndex];



                g.DrawImage(

                    image,

                    imageRect,

                    0,

                    0,

                    image.Width,

                    image.Height,

                    GraphicsUnit.Pixel);

            }

        }



        private void DrawBackground(

            Graphics g,

            int itemIndex,

            Rectangle rect, 

            bool selected)

        {

            switch (base.View)

            {

                case View.SmallIcon:

                case View.List:

                    rect.Inflate(-1, 0);

                    break;

            }



            if (selected)

            {

                Color baseColor = _selectedColor;

                Color borderColor = _selectedColor;

                Color innerBorderColor =

                    Color.FromArgb(150, 255, 255, 255);



                RenderBackgroundInternal(

                    g,

                    rect,

                    baseColor,

                    borderColor,

                    innerBorderColor,

                    0.45f,

                    true,

                    LinearGradientMode.Vertical);

            }

            else

            {

                if (base.View == View.List)

                {

                    Color backColor = itemIndex % 2 == 0 ?

                        _rowBackColor1 : _rowBackColor2;



                    using (SolidBrush brush = new SolidBrush(backColor))

                    {

                        g.FillRectangle(brush, rect);

                    }

                }

            }

        }



        private void DrawText(

            Graphics g, 

            ListViewItem item, 

            Rectangle textRect,

            bool selected)

        {

            StringFormat sf = StringFormat.GenericTypographic;

            switch (base.View)

            {

                case View.LargeIcon:

                    sf.Alignment = StringAlignment.Center;

                    sf.LineAlignment = StringAlignment.Near;

                    sf.Trimming = StringTrimming.EllipsisCharacter;

                    sf.FormatFlags &= ~(StringFormatFlags.LineLimit);

                    if (selected)

                    {

                        sf.FormatFlags &= ~StringFormatFlags.NoWrap;

                    }

                    break;

                case View.List:

                case View.SmallIcon:

                    textRect.Inflate(-1, 0);

                    sf.Alignment = StringAlignment.Near;

                    sf.LineAlignment = StringAlignment.Center;

                    sf.Trimming = StringTrimming.EllipsisCharacter;

                    sf.FormatFlags &= ~(StringFormatFlags.LineLimit);

                    break;

                case View.Tile:

                    textRect.Inflate(-2, 0);

                    sf.Alignment = StringAlignment.Near;

                    sf.LineAlignment = StringAlignment.Center;

                    sf.Trimming = StringTrimming.EllipsisCharacter;

                    sf.FormatFlags |= StringFormatFlags.NoWrap;

                    break;

            }



            if (base.View != View.Tile ||

                item.SubItems.Count == 1)

            {

                using (Brush brush = new SolidBrush(item.ForeColor))

                {

                    g.DrawString(

                        item.Text,

                        item.Font,

                        brush,

                        textRect,

                        sf);

                }

            }

            else

            {

                string subItemText = "A";

                int height;

                bool bBreak = false;

                Rectangle sunItemTextRect = textRect;

                foreach (ListViewItem.ListViewSubItem subItem in item.SubItems)

                {

                    if (!string.IsNullOrEmpty(subItem.Text))

                    {

                        subItemText = subItem.Text;

                    }



                    height = TextRenderer.MeasureText(

                        g, subItem.Text, subItem.Font).Height;

                    sunItemTextRect.Height = height;

                    if (sunItemTextRect.Bottom > textRect.Bottom)

                    {

                        sunItemTextRect.Height = 

                            textRect.Bottom - sunItemTextRect.Y;

                        bBreak = true;

                    }



                    using (Brush brush = new SolidBrush(subItem.ForeColor))

                    {

                        g.DrawString(

                            subItemText,

                            subItem.Font,

                            brush,

                            sunItemTextRect,

                            sf);

                    }

                    sunItemTextRect.Y += height;

                    if (bBreak)

                    {

                        break;

                    }

                }

            }

        }



        private void DrawSubItemDetails(

            DrawListViewSubItemEventArgs e)

        {

            Rectangle bounds = e.Bounds;

            ListViewItemStates itemState = e.ItemState;

            Graphics g = e.Graphics;

            ListViewItem item = e.Item;

            bool bSelected = 

                (itemState & ListViewItemStates.Selected) != 0;



            bool bDrawImage = false;

            bool bFistItem = false;

            int imageIndex = -1;



            if (e.ColumnIndex == 0)

            {

                bFistItem = true;

                if (item.ImageList != null)

                {

                    if(item.ImageIndex != -1)

                    {

                    imageIndex = item.ImageIndex;

                    }

                    else if (!string.IsNullOrEmpty(item.ImageKey))

                    {

                        imageIndex =

                            item.ImageList.Images.IndexOfKey(item.ImageKey);

                    } 



                    if(imageIndex != -1)

                    {

                        bDrawImage = true;

                    }

                }

            }



            Rectangle backRect = bounds;

            Rectangle imageRect = Rectangle.Empty;

            if (bDrawImage)

            {

                imageRect = item.GetBounds(ItemBoundsPortion.Icon);

                backRect = item.GetBounds(ItemBoundsPortion.Label);

                backRect.X += 2;

                backRect.Width -= 2;

            }



            if (bSelected &&

                (base.FullRowSelect ||

                (!base.FullRowSelect && bFistItem)))

            {

                backRect.Height--;

                Color baseColor = _selectedColor;

                Color borderColor = _selectedColor;

                Color innerBorderColor = Color.FromArgb(150, 255, 255, 255);



                RenderBackgroundInternal(

                    g,

                    backRect,

                    baseColor,

                    borderColor,

                    innerBorderColor,

                    0.45f,

                    false,

                    LinearGradientMode.Vertical);



                if (!base.FullRowSelect && bFistItem)

                {

                    backRect.Width--;

                    using (Pen pen = new Pen(borderColor))

                    {

                        g.DrawRectangle(pen, backRect);

                    }

                    backRect.Width++;

                }

                else

                {

                    Point[] points = new Point[4];

                    points[0] = new Point(backRect.X, backRect.Y);

                    points[1] = new Point(backRect.Right, backRect.Y);

                    points[2] = new Point(backRect.Right, backRect.Bottom);

                    points[3] = new Point(backRect.X, backRect.Bottom);

                    using (Pen pen = new Pen(borderColor))

                    {

                        if (bFistItem)

                        {

                            g.DrawLine(pen, points[0], points[1]);

                            g.DrawLine(pen, points[0], points[3]);

                            g.DrawLine(pen, points[2], points[3]);

                        }

                        if (e.ColumnIndex == ColumnCount - 1)

                        {

                            points[1].X--;

                            points[2].X--;

                            g.DrawLine(pen, points[0], points[1]);

                            g.DrawLine(pen, points[1], points[2]);

                            g.DrawLine(pen, points[2], points[3]);

                        }

                        else

                        {

                            g.DrawLine(pen, points[0], points[1]);

                            g.DrawLine(pen, points[2], points[3]);

                        }

                    }

                }

            }

            else

            {

                Color backColor = e.ItemIndex % 2 == 0 ?

                _rowBackColor1 : _rowBackColor2;



                using (SolidBrush brush = new SolidBrush(backColor))

                {

                    g.FillRectangle(brush, backRect);

                }

            }



            TextFormatFlags flags = GetFormatFlags(e.Header.TextAlign);

            if (bDrawImage)

            {

                g.InterpolationMode = InterpolationMode.HighQualityBicubic;

                if (bSelected)

                {

                    IntPtr hIcon = NativeMethods.ImageList_GetIcon(

                        item.ImageList.Handle,

                        imageIndex,

                        (int)NativeMethods.ImageListDrawFlags.ILD_SELECTED);

                    g.DrawIcon(Icon.FromHandle(hIcon), imageRect);

                    NativeMethods.DestroyIcon(hIcon);

                }

                else

                {

                    Image image = item.ImageList.Images[imageIndex];

                    g.DrawImage(

                        image, 

                        imageRect,

                        0,

                        0,

                        image.Width,

                        image.Height,

                        GraphicsUnit.Pixel);

                }



                Rectangle textRect = new Rectangle(

                    imageRect.Right + 3,

                    bounds.Y,

                    bounds.Width - imageRect.Right - 3,

                    bounds.Height);



                TextRenderer.DrawText(

                    g,

                    item.Text,

                    item.Font,

                    textRect,

                    item.ForeColor,

                    flags);

            }

            else

            {

                bounds.X += 3;

                TextRenderer.DrawText(

                    g,

                    e.SubItem.Text,

                    e.SubItem.Font,

                    bounds,

                    e.SubItem.ForeColor,

                    flags);

            }

        }



        #endregion

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作者：Starts_2000

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