在 WinForm ListView 控件中覆盖 Drawitem 事件

Question

在 WinForm ListView 控件中覆盖 Drawitem 事件

c#winformslistview

4

当失去焦点时，我希望我的ListView的选定项目仍然清晰可见（在Windows 7上是暗灰色）。我将HideSelection属性设置为False。

我想对列表视图做与此处针对TreeView控件所做的相同操作，即重写Drawnode事件：

C# WinForms highlight treenode when treeview doesnt have focus

我推测我需要将OwnerDraw属性设置为True并覆盖DrawItem事件，但我不确定在此事件中需要做什么.... :-)

- Chad

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- Dmitry · Accepted Answer

你需要类似这样的东西：

private void listView1_DrawColumnHeader(object sender, DrawListViewColumnHeaderEventArgs e)
{
    e.DrawDefault = true;
}

private void listView1_DrawSubItem(object sender, DrawListViewSubItemEventArgs e)
{
    const int TEXT_OFFSET = 1;    // I don't know why the text is located at 1px to the right. Maybe it's only for me.

    ListView listView = (ListView)sender;

    // Check if e.Item is selected and the ListView has a focus.
    if (!listView.Focused && e.Item.Selected)
    {
        Rectangle rowBounds = e.SubItem.Bounds;
        Rectangle labelBounds = e.Item.GetBounds(ItemBoundsPortion.Label);
        int leftMargin = labelBounds.Left - TEXT_OFFSET;
        Rectangle bounds = new Rectangle(rowBounds.Left + leftMargin, rowBounds.Top, e.ColumnIndex == 0 ? labelBounds.Width : (rowBounds.Width - leftMargin - TEXT_OFFSET), rowBounds.Height);
        TextFormatFlags align;
        switch (listView.Columns[e.ColumnIndex].TextAlign)
        {
            case HorizontalAlignment.Right:
                align = TextFormatFlags.Right;
                break;
            case HorizontalAlignment.Center:
                align = TextFormatFlags.HorizontalCenter;
                break;
            default:
                align = TextFormatFlags.Left;
                break;
        }
        TextRenderer.DrawText(e.Graphics, e.SubItem.Text, listView.Font, bounds, SystemColors.HighlightText,
            align | TextFormatFlags.SingleLine | TextFormatFlags.GlyphOverhangPadding | TextFormatFlags.VerticalCenter | TextFormatFlags.WordEllipsis);
    }
    else
        e.DrawDefault = true;
}

private void listView1_DrawItem(object sender, DrawListViewItemEventArgs e)
{
    ListView listView = (ListView)sender;

    // Check if e.Item is selected and the ListView has a focus.
    if (!listView.Focused && e.Item.Selected)
    {
        Rectangle rowBounds = e.Bounds;
        int leftMargin = e.Item.GetBounds(ItemBoundsPortion.Label).Left;
        Rectangle bounds = new Rectangle(leftMargin, rowBounds.Top, rowBounds.Width - leftMargin, rowBounds.Height);
        e.Graphics.FillRectangle(SystemBrushes.Highlight, bounds);
    }
    else
        e.DrawDefault = true;
}

编辑：针对 View = View.Details 和 FullRowSelect = true 进行了改进。
编辑2：考虑到列的不同对齐方式，还添加了自动省略标志。