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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);
}

 

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winform ListView应用之分组、重绘图标、网格线 (c# .net winform)