C# 拓展ComboBox設置線條屬性(轉)

時間 2019-11-26

標籤 c# 拓展 combobox 設置線條屬性欄目 C# 简体版

原文原文鏈接

C# 拓展ComboBox設置線條屬性
目前因爲項目須要，要實現線條屬性設置的功能，就如Visio中點擊線端時，能夠彈出一個窗口設置線條的各類屬性。ide

其中線條屬性選擇時，是在ComboBox控件中，顯示各類箭頭或者顏色等，此時就須要拓展ComboBox組件了。工具

開始作這個程序時，我沒有思路，在csdn上參考一位夥伴的程序，他主要是實現了顏色的設置。字體

廢話很少說了，上圖看看：this

步驟一：新建Winform工程spa

先添加用戶組件繼承自ComboBox。指針

系統自動生成的代碼：code

 1 <span style="font-family:Arial;"><span style="font-size:24px;"> </span><span style="font-size:14px;">   public partial class MyColorComboBox : ComboBox
 2     {
 3         public MyColorComboBox()
 4         {
 5             InitializeComponent();
 6             InitItems();
 7         }
 8  
 9         public MyColorComboBox(IContainer container)
10         {
11             container.Add(this);
12             InitializeComponent();
13             InitItems();
14         }
15     }</span></span>

由於咱們要顯示箭頭或者顏色，都是須要本身繪製圖形的。orm

步驟二：設置自定義組件的一些屬性blog

1 <span style="font-family:Arial;font-size:14px;"> private void InitItems()
2         {
3             this.DrawMode = DrawMode.OwnerDrawFixed;//手動繪製全部元素
4             this.DropDownStyle = ComboBoxStyle.DropDownList;//下拉框樣式設置爲不能編輯
5             this.Items.Clear();//清空原有項 
6         }</span>

 1 <span style="font-family:Arial;font-size:14px;"> public enum LineType
 2         { 
 3            TheStartOfLineWithArrow=0,//起始點有箭頭
 4            TheEndOfLineWithArrow,//終止點有箭頭
 5            LineWithArrows,//線的兩端帶箭頭
 6            TheStartOfBoldLineWithArrow,//粗線起始點帶箭頭
 7            TheEndOfBoldLineWithArrow,//粗線終止點帶箭頭
 8            BoldLineWithArrows,//粗線兩端帶箭頭
 9            TheStartOfLineWithPoint,//起始點帶圓點
10            TheEndOfLineWithPoint,//終止點帶圓點
11            LineWithPoints,//線兩端帶圓點
12            MoreLineType//更多線型選項
13         }</span>

步驟三：重寫OnDrawItem方法繼承

而後在OnDrawItem中寫繪製線條的方法

這裏主要是使用e.Graphics繪製圖形了。

 1 <span style="font-family:Arial;font-size:14px;"> protected override void OnDrawItem(DrawItemEventArgs e)
 2         {
 3             if (e.Index >= 0)//判斷是否須要重繪
 4             {
 5                 int typeId = int.Parse(this.Items[e.Index].ToString());//獲取選項id
 6  
 7                 Font font = new Font("宋體", 9);//定義字體
 8                 Rectangle rect = e.Bounds;
 9                 rect.Inflate(-2, -2);//縮放必定大小
10                 Pen pen = null;
11                 SolidBrush solidBrush = new SolidBrush(Color.Black);
12  
13                 float offSet = rect.Height / 2;
14                 float x = rect.Width / 10;
15                 float y = rect.Top + offSet;//若是設置成e.ItemHeigh*e.Index +offSet,則在選中節點後，因爲Item位置固定，所以Item不能顯示出來。
16  
17                 switch (typeId)
18                 {
19                     case (int)LineType.TheStartOfLineWithArrow:
20                         pen = new Pen(Color.Black, 1);
21                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y - offSet));//繪製起始點帶箭頭的線
22                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y + offSet));
23                         break;
24                     case (int)LineType.TheEndOfLineWithArrow:
25                         pen = new Pen(Color.Black, 1);
26                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y - offSet));//繪製終端帶箭頭的線
27                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y + offSet));
28                         break;
29                     case (int)LineType.LineWithArrows:
30                         pen = new Pen(Color.Black, 1);
31                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y - offSet));//繪製兩端帶箭頭的線 
32                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y + offSet));
33                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y - offSet));
34                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y + offSet));
35                         break;
36                     case (int)LineType.TheStartOfBoldLineWithArrow:
37                         pen = new Pen(Color.Black, 2);
38                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y - offSet));//繪製起始端帶箭頭的粗線
39                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y + offSet));
40                         break;
41                     case (int)LineType.TheEndOfBoldLineWithArrow:
42                         pen = new Pen(Color.Black, 2);
43                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y - offSet));//繪製終端帶箭頭的粗線
44                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y + offSet));
45                         break;
46                     case (int)LineType.BoldLineWithArrows:
47                         pen = new Pen(Color.Black, 2);
48                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y - offSet));
49                         e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(x + offSet, y + offSet));
50                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y - offSet));
51                         e.Graphics.DrawLine(pen, new PointF(8 * x, y), new PointF(8 * x - offSet, y + offSet));
52                         break;
53                     case (int)LineType.TheStartOfLineWithPoint:
54                         pen = new Pen(Color.Black, 1);
55                         e.Graphics.FillEllipse(solidBrush, new Rectangle(new Point((int)x - 3, (int)y - 3), new Size(8, 8)));//繪製起始端帶圓的線
56                         break;
57                     case (int)LineType.TheEndOfLineWithPoint:
58                         pen = new Pen(Color.Black, 1);
59                         e.Graphics.FillEllipse(solidBrush, new Rectangle(new Point((int)(8 * x) - 3, (int)y - 3), new Size(8, 8)));//繪製終端帶圓的線  
60                         break;
61                     case (int)LineType.LineWithPoints:
62                         pen = new Pen(Color.Black, 1);
63                         e.Graphics.FillEllipse(solidBrush, new Rectangle(new Point((int)x - 3, (int)y - 3), new Size(8, 8)));//繪製兩端都帶圓的線
64                         e.Graphics.FillEllipse(solidBrush, new Rectangle(new Point((int)(8 * x) - 3, (int)y - 3), new Size(8, 8)));
65                         break;
66                     case (int)LineType.MoreLineType:
67                         e.Graphics.DrawString("更多線型選項...", font, solidBrush, new PointF(x - 3, y - offSet));
68                         break;
69                     default:
70                         pen = new Pen(Color.Black, 1);
71                         break;
72                 }
73                 if (e.Index < 9)
74                 {
75                     e.Graphics.DrawLine(pen, new PointF(x, y), new PointF(8 * x, y));//繪製線
76                     Rectangle rectColor = new Rectangle(rect.Location, new Size(9 * (int)x, rect.Height));
77                     e.Graphics.DrawRectangle(Pens.Black, rectColor);//繪製邊框
78  
79                 }
80             }
81         }</span>