C#更改ListView项目/行的高度

Question

我想在listview中更改Item的/ Row的高度.

我找遍了那里,我想通,为了改变高度,我需要使用LBS_OWNERDRAWFIXED或MeasureItem或类似的东西.

问题是我不知道该做什么以及如何使用它.
任何人都可以帮助我吗？

编辑:
我不能使用ImageList黑客,因为我使用SmallImageList是真实的,我需要从ImageList图像大小不同的行高.

谢谢!

Answer 1

对于仍在努力解决这个问题的人来说,这是我使用的代码:

private void SetHeight(ListView listView, int height)
{
    ImageList imgList = new ImageList();
    imgList.ImageSize = new Size(1, height);
    listView.SmallImageList = imgList;
}

要使用它,只需:

SetHeight(lvConnections, 25);

Answer 2

你必须使用一点点黑客.诀窍是在StateImageList属性中使用图像列表.ListView将根据ImageList的ImageSize属性的高度调整其项高度.您不必为项目指定图像,但只需使用StateImageList将强制ListView进行调整.在下面的示例中,我将图像列表大小设置为32x32,从而产生32px高度的ListViewItem(s).

Answer 3

可以使用这个SmallImageList技巧来完成- 你必须要小心.ObjectListView - 围绕标准.NET的开源包装器ListView- 使用该技巧成功实现RowHeight属性.

如果每行需要32个像素,请分配ImageList16x32(宽x高),然后将每个图像放在32像素高度的垂直中间.

此屏幕截图显示32像素行和由于额外空间可能的自动换行:

ObjectListView这一切对你有用吗 事实上,如果你试图用ListView做任何事情,你应该认真考虑使用一个ObjectListView.它使许多困难的事情(例如按列类型,自定义工具提示排序)变得微不足道,并且几个不可能的事情(例如覆盖,虚拟列表上的组)成为可能.

Answer 4

可悲的是LBS_OWNERDRAWFIXED，这些年来没有人回答您最初的问题如何使用。

您接受的答案是集成一个庞大的项目（带有 3.3MB 的演示和文档）。但只是为了设置 ListView 的行高，这是过度膨胀的。

此处建议的其他解决方法（添加 ImageList）仅适用于增加行高。但它不允许真正设置独立于图像高度的 RowHeight。此外，默认行高取决于操作系统。例如，在 Windows 7 上，行数远高于 XP。你不能选择让它们更紧，只能更高。

但是用很少的行，你可以做你想做的。只需复制并粘贴以下类：

using System;
using System.Drawing;
using System.Diagnostics;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace ExtendedControls
{

public class ListViewEx : ListView
{
    #region Windows API

    /*
    struct MEASUREITEMSTRUCT 
    {
        public int    CtlType;     // Offset = 0
        public int    CtlID;       // Offset = 1
        public int    itemID;      // Offset = 2
        public int    itemWidth;   // Offset = 3
        public int    itemHeight;  // Offset = 4
        public IntPtr itemData;
    }
    */

    [StructLayout(LayoutKind.Sequential)]
    struct DRAWITEMSTRUCT
    {
        public int    ctlType;
        public int    ctlID;
        public int    itemID;
        public int    itemAction;
        public int    itemState;
        public IntPtr hWndItem;
        public IntPtr hDC;
        public int    rcLeft;
        public int    rcTop;
        public int    rcRight;
        public int    rcBottom;
        public IntPtr itemData;
    }

    // LVS_OWNERDRAWFIXED: The owner window can paint ListView items in report view. 
    // The ListView control sends a WM_DRAWITEM message to paint each item. It does not send separate messages for each subitem. 
    const int LVS_OWNERDRAWFIXED = 0x0400;
    const int WM_SHOWWINDOW      = 0x0018;
    const int WM_DRAWITEM        = 0x002B;
    const int WM_MEASUREITEM     = 0x002C;
    const int WM_REFLECT         = 0x2000;

    #endregion

    bool mb_Measured = false;
    int  ms32_RowHeight = 14;

    /// <summary>
    /// Constructor
    /// </summary>
    public ListViewEx()
    {
        SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
    }

    /// <summary>
    /// Sets the row height in Details view
    /// This property appears in the Visual Studio Form Designer
    /// </summary>
    [Category("Appearance")]  
    [Description("Sets the height of the ListView rows in Details view in pixels.")] 
    public int RowHeight
    {
        get { return ms32_RowHeight; }
        set 
        { 
            if (!DesignMode) Debug.Assert(mb_Measured == false, "RowHeight must be set before ListViewEx is created.");
            ms32_RowHeight = value; 
        }
    }

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams k_Params = base.CreateParams;
            k_Params.Style |= LVS_OWNERDRAWFIXED;
            return k_Params;
        }
    }

    /// <summary>
    /// The messages WM_MEASUREITEM and WM_DRAWITEM are sent to the parent control rather than to the ListView itself.
    /// They come here as WM_REFLECT + WM_MEASUREITEM and WM_REFLECT + WM_DRAWITEM
    /// They are sent from Control.WmOwnerDraw() --> Control.ReflectMessageInternal()
    /// </summary>
    protected override void WndProc(ref Message k_Msg)
    {
        base.WndProc(ref k_Msg); // FIRST

        switch (k_Msg.Msg)
        {
            case WM_SHOWWINDOW: // called when the ListView becomes visible
            {
                Debug.Assert(View == View.Details, "ListViewEx supports only Details view");
                Debug.Assert(OwnerDraw == false,   "In ListViewEx do not set OwnerDraw = true");
                break;
            }
            case WM_REFLECT + WM_MEASUREITEM: // called once when the ListView is created, but only in Details view
            {
                mb_Measured = true;

                // Overwrite itemHeight, which is the fifth integer in MEASUREITEMSTRUCT 
                Marshal.WriteInt32(k_Msg.LParam + 4 * sizeof(int), ms32_RowHeight);
                k_Msg.Result = (IntPtr)1;
                break;
            }
            case WM_REFLECT + WM_DRAWITEM: // called for each ListViewItem to be drawn
            {
                DRAWITEMSTRUCT k_Draw = (DRAWITEMSTRUCT) k_Msg.GetLParam(typeof(DRAWITEMSTRUCT));
                using (Graphics i_Graph = Graphics.FromHdc(k_Draw.hDC))
                {
                    ListViewItem i_Item = Items[k_Draw.itemID];

                    Color c_BackColor = i_Item.BackColor;
                    if (i_Item.Selected) c_BackColor = SystemColors.Highlight;
                    if (!Enabled)        c_BackColor = SystemColors.Control;

                    using (SolidBrush i_BackBrush = new SolidBrush(c_BackColor))
                    {
                        // Erase the background of the entire row
                        i_Graph.FillRectangle(i_BackBrush, i_Item.Bounds);
                    }

                    for (int S=0; S<i_Item.SubItems.Count; S++)
                    {
                        ListViewItem.ListViewSubItem i_SubItem = i_Item.SubItems[S];

                        // i_Item.SubItems[0].Bounds contains the entire row, rather than the first column only.
                        Rectangle k_Bounds = (S>0) ? i_SubItem.Bounds : i_Item.GetBounds(ItemBoundsPortion.Label);

                        // You can use i_Item.ForeColor instead of i_SubItem.ForeColor to get the same behaviour as without OwnerDraw
                        Color c_ForeColor = i_SubItem.ForeColor;
                        if (i_Item.Selected) c_ForeColor = SystemColors.HighlightText;
                        if (!Enabled)        c_ForeColor = SystemColors.ControlText;

                        TextFormatFlags e_Flags = TextFormatFlags.NoPrefix | TextFormatFlags.EndEllipsis | TextFormatFlags.VerticalCenter | TextFormatFlags.SingleLine;
                        switch (Columns[S].TextAlign)
                        {
                            case HorizontalAlignment.Center: e_Flags |= TextFormatFlags.HorizontalCenter; break;
                            case HorizontalAlignment.Right:  e_Flags |= TextFormatFlags.Right; break;
                        }

                        TextRenderer.DrawText(i_Graph, i_SubItem.Text, i_SubItem.Font, k_Bounds, c_ForeColor, e_Flags);
                    }
                }
                break;
            }
        }
    }
} // class
} // namespace

将 ListViewEx 添加到您的表单后，您将在 Visual Studio 表单设计器中看到一个新属性，该属性允许以像素为单位设置行高：

您在那里输入的值将以像素为单位的行高，并且在所有操作系统上都将受到严格遵守。我在 Windows XP、7 和 10 上对其进行了测试：

此外，我的班级与原始 ListView 相比还有两个优点：它可以无闪烁地绘制，并且尊重原始 Microsoft ListView 忽略的ForeColor和Font集ListViewSubItem。所以你可以用不同的颜色和字体绘制每个单元格。

重要提示：由于MSDN说LBS_OWNERDRAWFIXED已经设计只为详细视图（报表视图）。我的代码仅适用于这种模式，这是因为 Microsoft 是这样设计的。

另外请注意，设置ListView.OwnerDraw = true与使用LVS_OWNERDRAWFIXED.

我没有实现绘图图标，因为我不需要那个。但是您可以轻松添加它。