Listview的ownerdraw模式文本渲染问题

Question

我正在尝试实现所有者绘制的 ListView 因为基本控件会占用制表符，我需要在列中对齐值。

使用 中的示例MSDN 作为我能够接近的基础。我仍然遇到的唯一问题是，当文本不适合列时使用的省略号周期比默认文本渲染中的间隔更紧密；要点是，如果字体是粗体，则句点会一起形成下划线。

下面的程序演示了这个问题。它有 4 个 ListView：顶部的两个是使用默认渲染绘制的。底部的两个是业主绘制的，右侧的一对是粗体的。由于长度原因，我删除了不需要的所有内容以演示问题，这就是所有者绘制的 ListView 没有列标题的原因。

查看放大的屏幕截图，所有者绘制的 ListView 中的省略号周期间隔一个像素；默认绘图中的那些有两个像素的间距。当粗体将句点加宽到两个像素时，所有者绘制的句点合并在一起形成一个看起来像下划线的实心块。

文本渲染也存在其他细微差别；但省略号是唯一一个无需缩放即可明显看到的符号。然而，这些差异确实让我怀疑这个问题是一个更普遍的问题。 可能是 GDI 与 GDI+ 渲染？但我认为这只可能在应用程序级别有所不同。显然不是，切换 Application.SetCompatibleTextRenderingDefault() 不会影响任何内容。

using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public class Form1 : Form
    {
        private void ListViewDrawSubItem(object sender, 
                                         DrawListViewSubItemEventArgs e)
        {
            ListView listView = sender as ListView;
            using (StringFormat sf = new StringFormat())
            {
                // Draw the standard background.
                e.DrawBackground();
                sf.SetTabStops(0, new float[] {12, 12, 12, 12, 12});
                sf.FormatFlags = sf.FormatFlags | StringFormatFlags.NoWrap;
                sf.Trimming = StringTrimming.EllipsisCharacter;

                // Draw the header text.
                // passing the controls font directly causes an 
                // ArguementException);
                using (Font headerFont = new Font(listView.Font.Name, 
                                                  listView.Font.Size, 
                                                  listView.Font.Style))
                {
                    e.Graphics.DrawString(e.SubItem.Text, headerFont, 
                                          Brushes.Black, e.Bounds, sf);
                }
            }
        }

        public Form1()
        {
            InitializeComponent();
            LoadData(listView1);
            LoadData(listView2);
            LoadData(listView3);
            LoadData(listView4);
        }

        private void LoadData(ListView listView)
        {
            listView.Columns.Add("first", 35);
            listView.Columns.Add("second", 75);

            for (int i = 0; i < 5; i++)
            {
                listView.Items.Add("test");
                listView.Items[i].SubItems.Add("test test test test");
            }
        }

        #region from Form1.Designer
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be 
        /// disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.listView1 = new System.Windows.Forms.ListView();
            this.listView2 = new System.Windows.Forms.ListView();
            this.listView3 = new System.Windows.Forms.ListView();
            this.listView4 = new System.Windows.Forms.ListView();
            this.SuspendLayout();
            // 
            // listView1
            // 
            this.listView1.Location = new System.Drawing.Point(12, 12);
            this.listView1.Name = "listView1";
            this.listView1.Size = new System.Drawing.Size(121, 116);
            this.listView1.TabIndex = 0;
            this.listView1.UseCompatibleStateImageBehavior = false;
            this.listView1.View = System.Windows.Forms.View.Details;
            // 
            // listView2
            // 
            this.listView2.Font = new System.Drawing.Font("Microsoft Sans Serif", 
                                       8.25F, System.Drawing.FontStyle.Bold,
                                       System.Drawing.GraphicsUnit.Point, 
                                       ((byte)(0)));
            this.listView2.Location = new System.Drawing.Point(151, 12);
            this.listView2.Name = "listView2";
            this.listView2.Size = new System.Drawing.Size(121, 116);
            this.listView2.TabIndex = 1;
            this.listView2.UseCompatibleStateImageBehavior = false;
            this.listView2.View = System.Windows.Forms.View.Details;
            // 
            // listView3
            // 
            this.listView3.Location = new System.Drawing.Point(12, 134);
            this.listView3.Name = "listView3";
            this.listView3.OwnerDraw = true;
            this.listView3.Size = new System.Drawing.Size(121, 116);
            this.listView3.TabIndex = 2;
            this.listView3.UseCompatibleStateImageBehavior = false;
            this.listView3.View = System.Windows.Forms.View.Details;
            this.listView3.DrawSubItem += new 
                          System.Windows.Forms.DrawListViewSubItemEventHandler(
                          this.ListViewDrawSubItem);
            // 
            // listView4
            // 
            this.listView4.Font = new System.Drawing.Font("Microsoft Sans Serif", 
                                       8.25F, System.Drawing.FontStyle.Bold,
                                       System.Drawing.GraphicsUnit.Point, 
                                       ((byte)(0)));
            this.listView4.Location = new System.Drawing.Point(151, 134);
            this.listView4.Name = "listView4";
            this.listView4.OwnerDraw = true;
            this.listView4.Size = new System.Drawing.Size(121, 116);
            this.listView4.TabIndex = 3;
            this.listView4.UseCompatibleStateImageBehavior = false;
            this.listView4.View = System.Windows.Forms.View.Details;
            this.listView4.DrawSubItem += new 
                          System.Windows.Forms.DrawListViewSubItemEventHandler(
                          this.ListViewDrawSubItem);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 262);
            this.Controls.Add(this.listView4);
            this.Controls.Add(this.listView3);
            this.Controls.Add(this.listView2);
            this.Controls.Add(this.listView1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.ListView listView1;
        private System.Windows.Forms.ListView listView2;
        private System.Windows.Forms.ListView listView3;
        private System.Windows.Forms.ListView listView4;
        #endregion

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

Answer 1

我找到了绘制子项方法的一个偶然实现。我的主要警告是选项卡大小是固定的（尽管如果需要更改它，我可以下降到 win32）；据报道，我在我的机器上工作时所需的标志组合在 MSDN 中是相互不兼容的。

private void ListViewDrawSubItem(object sender, DrawListViewSubItemEventArgs e)
{
    //toggle colors if the item is highlighted 
    if (e.Item.Selected && e.Item.ListView.Focused)
    {
        e.SubItem.BackColor = SystemColors.Highlight;
        e.SubItem.ForeColor = e.Item.ListView.BackColor;
    }
    else if (e.Item.Selected && !e.Item.ListView.Focused)
    {
        e.SubItem.BackColor = SystemColors.Control;
        e.SubItem.ForeColor = e.Item.ListView.ForeColor;
    }
    else
    {
        e.SubItem.BackColor = e.Item.ListView.BackColor;
        e.SubItem.ForeColor = e.Item.ListView.ForeColor;
    }

    // Draw the standard header background.
    e.DrawBackground();
        
    //add a 2 pixel buffer the match default behavior
    Rectangle rec = new Rectangle(e.Bounds.X + 2, e.Bounds.Y+2, 
                                  e.Bounds.Width - 4, e.Bounds.Height-4);

    //TODO  Confirm combination of TextFormatFlags.EndEllipsis and 
    //TextFormatFlags.ExpandTabs works on all systems.  MSDN claims they're 
    //exclusive but on Win7-64 they work.
    TextFormatFlags flags = TextFormatFlags.Left | TextFormatFlags.EndEllipsis | 
                            TextFormatFlags.ExpandTabs |
                            TextFormatFlags.SingleLine;

    //If a different tab stop than the default is needed, will have to p/invoke 
    //DrawTextEx from win32.
    TextRenderer.DrawText(e.Graphics, e.SubItem.Text, e.Item.ListView.Font, rec, 
                          e.SubItem.ForeColor, flags);
}