首页 > 代码库 > winform ListView应用之分组、重绘图标、网格线 (c# .net winform)
winform ListView应用之分组、重绘图标、网格线 (c# .net winform)
最近在winform应用中需要用到可分组的数据列表功能,DataGridView默认没有提供分组的功能,而OutlookGrid(http://www.codeproject.com/KB/grid/OutlookGrid.aspx)用起来又是相当的麻烦,最后发现了ObjectListView(objectlistview.sourceforge.net),功能相当的强大,强大到我不需要那么多的功能,额~~所以决定参照它的实现,对ListView做一个简单的扩展(注:本文仅针对ListView的View属性为Details)。
首先为ListView添加好列:
listViewEx1.Columns.AddRange( new ColumnHeader[] { new ColumnHeader( "列1" ), new ColumnHeader( "列2" ), new ColumnHeader( "列3" ) }); |
分组
这是ListView自带的功能,用起来也很简单,只需要把ShowGroups设置为true(默认为true),再为ListView添加ListViewGroup,并为ListViewItem设置Group即可,代码如下:
ListViewGroup g = new ListViewGroup( "分组" ); listViewEx1.Groups.Add(g); ListViewItem item = new ListViewItem( "数据项" , g); listViewEx1.Items.Add(item); |
接下来的重绘方法,就需要通过继承ListView并重写OnDrawSubItem(DrawListViewSubItemEventArgs e)方法来实现,在重写此方法之前,必须设置ListView的OwnerDraw属性为true,用于启用重绘。
给ListViewSubItem设置图标
ListView默认可以设置ImageIndex来显示图标,但是只能设置在每个ListViewItem上,即每一行数据只能有一个图标,若要每个ListViewSubItem都能设置图标,则需要通过重写OnDrawSubItem(DrawListViewSubItemEventArgs e)方法来实现,关键代码为:
Graphics g = e.Graphics; Rectangle r = e.Bounds; Rectangle imageBounds = new Rectangle(r.Location, image.Size); //image为具体的图标文件 g.DrawImage(image, imageBounds); //通过DrawImage方法绘制图标 |
对这种方法简单的改造,可以为每一列设置单独的图标。
网格线
ListView在设置了分组的情况下,GridLines属性就无效了,所以如果需要显示网格线,也需要通过重写OnDrawSubItem(DrawListViewSubItemEventArgs e)方法来实现,关键代码为:
Graphics g = e.Graphics; Rectangle r = e.Bounds; using (Pen pen = new Pen(Color.Gray)) { g.DrawRectangle(pen, r.X, r.Y, r.Width, r.Height + 1); //高度加1使横向线条重叠 } |
以上代码画了灰色的网格线,也可以简单改造以实现自定义的网络线颜色。
选中的背景
在重写OnDrawSubItem(DrawListViewSubItemEventArgs e)方法之后,选中ListView的行,默认的背景色不会出现,所以还得把选中状态的背景色显示出来,关键代码为:
if ((e.ItemState & ListViewItemStates.Selected) == ListViewItemStates.Selected) { using (SolidBrush brush = new SolidBrush(Color.Blue)) { g.FillRectangle(brush, r); } } |
以上代码为选中的列绘制了蓝色的背景,同样也可以扩展以上代码来实现自定义背景色。
呈现原始文本
在重写OnDrawSubItem(DrawListViewSubItemEventArgs e)之后,原来的文本内容同样也会像背景一样丢失了,所以需要把原来的文本重新绘制出来,关键代码如下:
Graphics g = e.Graphics; Rectangle r = e.Bounds; TextRenderer.DrawText( g, e.SubItem.Text, e.SubItem.Font, r, e.SubItem.ForeColor, TextFormatFlags.Left); |
其他
1、自动调整列大小:调用AutoResizeColumns方法,listView1.AutoResizeColumns(ColumnHeaderAutoResizeStyle.ColumnContent)
2、隐藏列头:设置HeaderStyle属性,listView1.HeaderStyle = ColumnHeaderStyle.None
3、选择整行:设置FullRowSelect为true
4、行双击事件:绑定ListView的MouseDoubleClick事件,代码如下:
void listView1_MouseDoubleClick( object sender, MouseEventArgs e) { ListViewHitTestInfo info = listView1.HitTest(e.Location); if (info != null && info.Item != null ) { //... } } |
完整的代码
public class ListViewEx : ListView { public ListViewEx() : base () { this .OwnerDraw = true ; //用于启用重绘 } /// <summary> /// 图标 /// </summary> public Image Icon { get ; set ; } /// <summary> /// 重绘图标 /// </summary> public bool IsDrawIcon { get ; set ; } /// <summary> /// 重绘网格线 /// </summary> public bool IsDrawGridLines { get ; set ; } /// <summary> /// 重绘图标列 /// </summary> /// <param name="e"></param> protected override void OnDrawSubItem(DrawListViewSubItemEventArgs e) { if (View != View.Details || e.ItemIndex == -1) { e.DrawDefault = true ; return ; } Rectangle r = e.Bounds; Graphics g = e.Graphics; DrawSelectedBackground(e, g, r); int paddingLeft = 0; if (IsDrawIcon) { paddingLeft = this .DrawIcon(g, r, this .Icon, e.Item.BackColor).Width; } if (IsDrawGridLines) { using (Pen pen = new Pen(Color.Gray)) { g.DrawRectangle(pen, r.X, r.Y, r.Width, r.Height + 1); //高度加1使横向线条重叠 } } if (! string .IsNullOrEmpty(e.SubItem.Text)) { this .DrawText(e, g, r, paddingLeft); } } /// <summary> /// 重绘选中时背景 /// </summary> private void DrawSelectedBackground(DrawListViewSubItemEventArgs e, Graphics g, Rectangle r) { if ((e.ItemState & ListViewItemStates.Selected) == ListViewItemStates.Selected) { using (SolidBrush brush = new SolidBrush(Color.Blue)) { g.FillRectangle(brush, r); } } } /// <summary> /// 重绘图标 /// </summary> private Size DrawIcon(Graphics g, Rectangle r, Image image, Color backColor) { Rectangle imageBounds = new Rectangle(r.Location, image.Size); if (image.Height > r.Height) { float scaleRatio = ( float )r.Height / ( float )image.Height; imageBounds.Width = ( int )(( float )Icon.Width * scaleRatio); imageBounds.Height = r.Height - 1; } //使图标不会紧贴着每一列的左上角 imageBounds.X += 1; imageBounds.Y += 1; g.DrawImage(image, imageBounds); return imageBounds.Size; } /// <summary> /// 重绘文本 /// </summary> private void DrawText(DrawListViewSubItemEventArgs e, Graphics g, Rectangle r, int paddingLeft) { TextFormatFlags flags = GetFormatFlags(e.Header.TextAlign); r.X += 1 + paddingLeft; //重绘图标时,文本右移 TextRenderer.DrawText( g, e.SubItem.Text, e.SubItem.Font, r, e.SubItem.ForeColor, flags); } /// <summary> /// 获取文本对齐 /// </summary> private TextFormatFlags GetFormatFlags( HorizontalAlignment align) { TextFormatFlags flags = TextFormatFlags.EndEllipsis | TextFormatFlags.VerticalCenter; switch (align) { case HorizontalAlignment.Center: flags |= TextFormatFlags.HorizontalCenter; break ; case HorizontalAlignment.Right: flags |= TextFormatFlags.Right; break ; case HorizontalAlignment.Left: flags |= TextFormatFlags.Left; break ; } return flags; } } |
相关的演示代码:
public Form1() { InitializeComponent(); ListViewEx listViewEx1 = new ListViewEx(); listViewEx1.Icon = Resources.application; listViewEx1.IsDrawGridLines = true ; listViewEx1.IsDrawIcon = true ; listViewEx1.Location = new Point(0, 0); listViewEx1.Name = "listViewEx1" ; listViewEx1.Size = new Size(284, 265); listViewEx1.Dock = DockStyle.Fill; listViewEx1.FullRowSelect = true ; listViewEx1.UseCompatibleStateImageBehavior = false ; listViewEx1.View = View.Details; listViewEx1.HeaderStyle = ColumnHeaderStyle.None; listViewEx1.Columns.AddRange( new ColumnHeader[] { new ColumnHeader(), new ColumnHeader(), new ColumnHeader() }); for ( int i = 1; i <= 3; i++) { ListViewGroup g = new ListViewGroup( "分组" + i.ToString()); listViewEx1.Groups.Add(g); for ( int j = 1; j <= 5; j++) { ListViewItem item = new ListViewItem(j.ToString(), g); item.SubItems.Add((i + j).ToString()); item.SubItems.Add((i * j).ToString()); listViewEx1.Items.Add(item); } } this .Controls.Add(listViewEx1); } |
DEMO下载
winform ListView应用之分组、重绘图标、网格线 (c# .net winform)