美化combox 用法 —— 为其添加图片，改变显示方式

对C# 中Combox控件的一些简单的操作，改变其显示特性，主要是改变其中的项的属性

我们需要注意的是：每次为Combox添加项的时候，就会触发DrawItem事件，而我们正是通过DrawItem来改变Combox的显示特性的

 

 

[c-sharp]  view plain copy

1. using System;  
2. using System.Collections.Generic;  
3. using System.ComponentModel;  
4. using System.Data;  
5. using System.Drawing;  
6. using System.Linq;  
7. using System.Text;  
8. using System.Windows.Forms;  
9. using System.Collections;  
10.   
11. namespace Combox_Image  
12. {  
13.     public partial class Form1 : Form  
14.     {  
15.         ArrayList brushArray = new ArrayList() ;  
16.         ArrayList fontArray = new ArrayList() ;  
17.   
18.         public Form1()  
19.         {  
20.             InitializeComponent();  
21.         }  
22.   
23.         private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)  
24.         {  
25.             //确定画布  
26.             Graphics g = e.Graphics;  
27.             //绘制区域  
28.             Rectangle r = e.Bounds;  
29.             Font fn = null;  
30.             if (e.Index >= 0)  
31.             {  
32.                 //设置字体、字符串格式、对齐方式  
33.                 fn = (Font)fontArray[e.Index];  
34.                 string s = (string)comboBox1.Items[e.Index];  
35.                 StringFormat sf = new StringFormat();  
36.                 sf.Alignment = StringAlignment.Near;  
37.                 //根据不同的状态用不同的颜色表示  
38.                 if (e.State == (DrawItemState.NoAccelerator | DrawItemState.NoFocusRect))  
39.                 {  
40.                     e.Graphics.FillRectangle(new SolidBrush(Color.Red), r);  
41.                     e.Graphics.DrawString(s, fn, new SolidBrush(Color.Black), r, sf);  
42.                     e.DrawFocusRectangle();  
43.                 }  
44.                 else  
45.                 {  
46.                     e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue), r);  
47.                     e.Graphics.DrawString(s, fn, new SolidBrush(Color.Red), r, sf);  
48.                     e.DrawFocusRectangle();  
49.                 }  
50.             }  
51.   
52.         }  
53.   
54.         private void Form1_Load(object sender, EventArgs e)  
55.         {  
56.             fontArray.Add(new Font("Ariel", 8, FontStyle.Bold));  
57.             fontArray.Add(new Font("Courier", 8, FontStyle.Italic));  
58.             fontArray.Add(new Font("Veranda", 8, FontStyle.Bold));  
59.             fontArray.Add(new Font("System", 8, FontStyle.Strikeout));  
60.             fontArray.Add(new Font("Century SchoolBook", 8, FontStyle.Underline));  
61.             fontArray.Add(new Font("Helevctia", 8, FontStyle.Italic));  
62.             //创建画刷  
63.             brushArray.Add(new SolidBrush(Color.Red));  
64.             brushArray.Add(new SolidBrush(Color.Blue));  
65.             brushArray.Add(new SolidBrush(Color.Green));  
66.             brushArray.Add(new SolidBrush(Color.Yellow));  
67.             brushArray.Add(new SolidBrush(Color.Black));  
68.             brushArray.Add(new SolidBrush(Color.Azure));  
69.             brushArray.Add(new SolidBrush(Color.Firebrick));  
70.             brushArray.Add(new SolidBrush(Color.DarkMagenta));  
71.             brushArray.Add(new SolidBrush(Color.DarkTurquoise));  
72.             brushArray.Add(new SolidBrush(Color.Khaki));  
73.             //画comboBox1，注意它要调用comboBox1_DrawItem来画  
74.             comboBox1.Items.Add("中国");  
75.             comboBox1.Items.Add("巴西");  
76.             comboBox1.Items.Add("哥斯达黎加");  
77.             comboBox1.Items.Add("土耳其");  
78.             comboBox1.Items.Add("韩国");  
79.             comboBox1.Items.Add("日本");  
80.             //画comboBox2，注意它要调用comboBox2_DrawItem来画  
81.             comboBox2.Items.Add("");  
82.             comboBox2.Items.Add("");  
83.             comboBox2.Items.Add("");  
84.             comboBox2.Items.Add("");  
85.             comboBox2.Items.Add("");  
86.             comboBox2.Items.Add("");  
87.             comboBox2.Items.Add("");  
88.             comboBox2.Items.Add("");  
89.             comboBox2.Items.Add("");  
90.             comboBox2.Items.Add("");  
91.             //画comboBox3，注意它要调用comboBox3_DrawItem来画  
92.             comboBox3.Items.Add("赵微");  
93.             comboBox3.Items.Add("舒淇");  
94.             comboBox3.Items.Add("谌豹");  
95.             comboBox3.Items.Add("郑巧玲");  
96.         }  
97.   
98.         private void comboBox2_DrawItem(object sender, DrawItemEventArgs e)  
99.         {  
100.             Graphics g = e.Graphics;  
101.             Rectangle r = e.Bounds;  
102.             if (e.Index >= 0)  
103.             {  
104.                 //设置字符串前矩形块rd的大小  
105.                 Rectangle rd = r;  
106.                 rd.Width = rd.Left + 20;  
107.                 Rectangle rt = r;  
108.                 r.X = rd.Right;  
109.                 //用不同的颜色画矩形块  
110.                 SolidBrush b = (SolidBrush)brushArray[e.Index];  
111.                 g.FillRectangle(b, rd);  
112.                 //设置字符串的格式  
113.                 StringFormat sf = new StringFormat();  
114.                 sf.Alignment = StringAlignment.Near;  
115.                 if (e.State == (DrawItemState.NoAccelerator | DrawItemState.NoFocusRect))  
116.                 {  
117.                     //字符串背景  
118.                     e.Graphics.FillRectangle(new SolidBrush(Color.White), r);  
119.                     //显示字符串  
120.                     e.Graphics.DrawString(b.Color.Name, new Font("Ariel", 8, FontStyle.Bold), new SolidBrush(Color.Black), r, sf);  
121.                     //绘制取得焦点时的虚线框  
122.                     e.DrawFocusRectangle();  
123.                 }  
124.                 else  
125.                 {  
126.                     e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue), r);  
127.                     e.Graphics.DrawString(b.Color.Name, new Font("Veranda", 8, FontStyle.Bold), new SolidBrush(Color.Red), r, sf);  
128.                     e.DrawFocusRectangle();  
129.                 }  
130.             }  
131.   
132.         }  
133.   
134.         private void comboBox3_DrawItem(object sender, DrawItemEventArgs e)  
135.         {  
136.             Graphics g = e.Graphics;  
137.             Rectangle r = e.Bounds;  
138.             Size imageSize = imageList1.ImageSize;  
139.             Font fn = null;  
140.             if (e.Index >= 0)  
141.             {  
142.                 fn = (Font)fontArray[0];  
143.                 string s = (string)comboBox3.Items[e.Index];  
144.                 StringFormat sf = new StringFormat();  
145.                 sf.Alignment = StringAlignment.Near;  
146.                 if (e.State == (DrawItemState.NoAccelerator | DrawItemState.NoFocusRect))  
147.                 {  
148.                     //画条目背景  
149.                     e.Graphics.FillRectangle(new SolidBrush(Color.Red), r);  
150.                     //绘制图像  
151.                     imageList1.Draw(e.Graphics, r.Left, r.Top, e.Index);  
152.                     //显示字符串  
153.                     e.Graphics.DrawString(s, fn, new SolidBrush(Color.Black), r.Left + imageSize.Width, r.Top);  
154.                     //显示取得焦点时的虚线框  
155.                     e.DrawFocusRectangle();  
156.                 }  
157.                 else  
158.                 {  
159.                     e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue), r);  
160.                     imageList1.Draw(e.Graphics, r.Left, r.Top, e.Index);  
161.                     e.Graphics.DrawString(s, fn, new SolidBrush(Color.Black), r.Left + imageSize.Width, r.Top);  
162.                     e.DrawFocusRectangle();  
163.                 }  
164.             }  
165.         }  
166.     }  
167. }  

 三个Combox的效果如下图所示： 

 

 

原文地址：http://blog.youkuaiyun.com/nidexuanzhe/article/details/6264765