封装类
public class ColorComboBox : ComboBox{private int _colorBoxWidth = 20;private int _colorBoxMargin = 2;private Color _colorBoxBorderColor = Color.Black;public ColorComboBox(){DrawMode = DrawMode.OwnerDrawFixed;DropDownStyle = ComboBoxStyle.DropDownList;LoadAllKnownColors(); // 加载所有已知颜色// --- 添加以下代码来设置默认选中红色 ---// 方法1：通过索引查找 (推荐，准确)for (int i = 0; i < Items.Count; i++){if (Items[i] is Color color && color.ToArgb() == Color.Red.ToArgb()){this.SelectedIndex = i;break;}}}public int ColorBoxWidth{get { return _colorBoxWidth; }set { _colorBoxWidth = value; Invalidate(); }}public int ColorBoxMargin{get { return _colorBoxMargin; }set { _colorBoxMargin = value; Invalidate(); }}public Color ColorBoxBorderColor{get { return _colorBoxBorderColor; }set { _colorBoxBorderColor = value; Invalidate(); }}public string ColorMember { get; set; } /// <summary>/// 加载所有 KnownColor 枚举的颜色到下拉项中。/// 如果已设置 DataSource，则此方法无效（因为 DataSource 优先）。/// </summary>public void LoadAllKnownColors(){if (DataSource != null)return; // 数据绑定状态下不加载 Items.Clear();foreach (KnownColor kc in Enum.GetValues(typeof(KnownColor))){Items.Add(Color.FromKnownColor(kc));}}protected override void OnDrawItem(DrawItemEventArgs e){if (e.Index < 0 || e.Index >= Items.Count){base.OnDrawItem(e);return;}object item = Items[e.Index];if (item == null){base.OnDrawItem(e);return;}e.DrawBackground();Color itemColor = GetItemColor(item);string displayText = GetItemDisplayText(item);Rectangle boxRect = new Rectangle(e.Bounds.Left + ColorBoxMargin,e.Bounds.Top + ColorBoxMargin,ColorBoxWidth,e.Bounds.Height - ColorBoxMargin * 2);using (SolidBrush colorBrush = new SolidBrush(itemColor)){e.Graphics.FillRectangle(colorBrush, boxRect);}using (Pen borderPen = new Pen(ColorBoxBorderColor)){e.Graphics.DrawRectangle(borderPen, boxRect);}TextRenderer.DrawText(e.Graphics,displayText,e.Font,new Point(boxRect.Right + ColorBoxMargin, e.Bounds.Top + ColorBoxMargin),e.ForeColor);e.DrawFocusRectangle();}private Color GetItemColor(object item){if (!string.IsNullOrEmpty(ColorMember)){var prop = item.GetType().GetProperty(ColorMember);if (prop != null){object value = prop.GetValue(item);if (value is Color)return (Color)value;if (value is string)return ColorFromString(value.ToString());try{return ColorFromString(value.ToString());}catch { }}}if (item is Color)return (Color)item;return ColorFromString(item.ToString());}private Color ColorFromString(string name){try{return Color.FromName(name);}catch{return Color.Empty;}}private string GetItemDisplayText(object item){return GetItemText(item);}}