c# - Listview 问题与 ownerdraw 模式文本呈现

Question

我正在尝试实现所有者绘制的 ListView，因为基本控件占用了制表符，我需要用它来对齐列中的值。

使用 MSDN 中的示例作为基地，我能够接近。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句点比默认文本呈现更紧密地间隔在一起；重点是如果字体是粗体，句号会一起变成下划线。

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。底部的两个是所有者绘制的，右侧的一对是粗体。由于篇幅原因，我删除了所有不需要的内容以演示问题，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 中的省略号间隔为一个像素；默认图形中的那些有两个像素的间距。当粗体将句点扩大到两个像素时，所有者绘制的句点会合并成一个看起来像下划线的实心 block 。

文本渲染也有其他细微差别；但省略号是唯一在不缩放的情况下很明显的省略号。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？除了我认为这只会在应用程序级别有所不同。显然不会，切换 Application.SetCompatibleTextRenderingDefault() 不会影响任何东西。

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

我已经找到了绘制子项方法的临时实现。我的主要注意事项是选项卡大小是固定的(尽管如果需要更改它我可以降到 win32)；并且我在我的机器上工作时需要的标志组合在 MSDN 中被报告为相互不兼容。

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);
}