使用WPF动态生成Code 39条形码

最近在看些条形码方面相关的资料，而如果只是看的话，效果似乎并不怎么好，所以决定动手做点Demo，以增强对相关知识的记忆。

 

这里是一个我编写的使用WPF生成Code 39的例子，Code 39的编码很简单，故而第一次先用它做为尝试。

 

标准的Code 39只支持43个字符，0~9，A~Z，-，.，$， /， +， %以及空格。除此之外，*用于起始和终止符号。而通过使用两个编码符的扩展，则可以支持所有的Acsii码字符。相关知识可以在维基百科上找到。

 

由于是WPF，Demo分为两个文件，xaml文件包含界面布局相关的代码：

 1     <Window x:Class="Code39Demo.MainWindow"  
 2             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
 3             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
 4             Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">  
 5         <Grid>  
 6             <Grid.RowDefinitions>  
 7                 <RowDefinition></RowDefinition>  
 8                 <RowDefinition></RowDefinition>  
 9             </Grid.RowDefinitions>  
10             <TextBox Name="Textbox1" VerticalContentAlignment="Center" TextChanged="Textbox1_TextChanged"></TextBox>  
11             <Canvas Name="Canvas1" Grid.Row="1"></Canvas>  
12         </Grid>  
13     </Window>  

xaml.cs文件是具体的实现，主要功能是在文本框内容改变的时候动态构成Code 39条形码：

  1     using System.Collections.Generic;  
  2     using System.Text;  
  3     using System.Text.RegularExpressions;  
  4     using System.Windows;  
  5     using System.Windows.Controls;  
  6     using System.Windows.Media;  
  7     using System.Windows.Shapes;  
  8        
  9     namespace Code39Demo  
 10     {  
 11         /// <summary>  
 12         /// Interaction logic for MainWindow.xaml  
 13         /// </summary>  
 14         public partial class MainWindow : Window  
 15         {  
 16             public MainWindow()  
 17             {  
 18                 InitializeComponent();  
 19             }  
 20        
 21             private void Window_Loaded(object sender, RoutedEventArgs e)  
 22             {  
 23                 Textbox1.Focus();  
 24             }  
 25        
 26             private void Textbox1_TextChanged(object sender, TextChangedEventArgs e)  
 27             {  
 28                 Canvas1.Children.Clear();  
 29        
 30                 TextBox textBox = e.Source as TextBox;  
 31                 if (textBox != null)  
 32                 {  
 33                     string content = textBox.Text;  
 34                     if (string.IsNullOrEmpty(content))  
 35                     {  
 36                         textBox.BorderBrush = null;  
 37                         return;  
 38                     }  
 39        
 40                     string code = string.Empty;  
 41                     bool result = TryConvertCode(content, out code);  
 42                     if (!result)  
 43                     {  
 44                         textBox.BorderBrush = new SolidColorBrush(Colors.Red);  
 45                         textBox.BorderThickness = new Thickness(2);  
 46                         return;  
 47                     }  
 48                     else  
 49                     {  
 50                         textBox.BorderBrush = null;  
 51                     }  
 52        
 53                     int thinWidth = 3;  
 54                     int thickWidth = 3 * thinWidth;  
 55                     int currentPos = 10;  
 56        
 57                     for (int i = 0; i < code.Length; i++)  
 58                     {  
 59                         Rectangle r = new Rectangle();  
 60                         r.Height = 150;  
 61        
 62                         Canvas.SetLeft(r, currentPos);  
 63        
 64                         switch (code[i])  
 65                         {  
 66                             case 'N':  
 67                                 {  
 68                                     r.Fill = new SolidColorBrush(Colors.Black);  
 69                                     currentPos += thinWidth;  
 70                                     r.Width = thinWidth;  
 71                                     break;  
 72                                 }  
 73                             case 'n':  
 74                                 {  
 75                                     r.Fill = new SolidColorBrush(Colors.White);  
 76                                     currentPos += thinWidth;  
 77                                     r.Width = thinWidth;  
 78                                     break;  
 79                                 }  
 80                             case 'W':  
 81                                 {  
 82                                     r.Fill = new SolidColorBrush(Colors.Black);  
 83                                     currentPos += thickWidth;  
 84                                     r.Width = thickWidth;  
 85                                     break;  
 86                                 }  
 87                             case 'w':  
 88                                 {  
 89                                     r.Fill = new SolidColorBrush(Colors.White);  
 90                                     currentPos += thickWidth;  
 91                                     r.Width = thickWidth;  
 92                                     break;  
 93                                 }  
 94                         }  
 95        
 96                         Canvas1.Children.Add(r);  
 97                     }  
 98                 }  
 99             }  
100        
101             private bool TryConvertCode(string content, out string code)  
102             {  
103                 code = string.Empty;  
104                 string c = "*" + content + "*";  
105                 StringBuilder sb = new StringBuilder();  
106        
107                 for (int i = 0; i < c.Length; i++)  
108                 {  
109                     string value = string.Empty;  
110                     bool result = _code39Map.TryGetValue(c[i], out value);  
111                     if (!result)  
112                     {  
113                         return false;  
114                     }  
115        
116                     sb.Append(value);  
117                     sb.Append('n');  
118                 }  
119        
120                 code = sb.Remove(sb.Length - 1, 1).ToString();  
121        
122                 return true;  
123             }  
124        
125             private static Dictionary<char, string> _code39Map = new Dictionary<char, string>();  
126        
127             static MainWindow()  
128             {  
129                 _code39Map['0'] = "NnNwWnWnN";  
130                 _code39Map['1'] = "WnNwNnNnW";  
131                 _code39Map['2'] = "NnWwNnNnW";  
132                 _code39Map['3'] = "WnWwNnNnN";  
133                 _code39Map['4'] = "NnNwWnNnW";  
134                 _code39Map['5'] = "WnNwWnNnN";  
135                 _code39Map['6'] = "NnWwWnNnN";  
136                 _code39Map['7'] = "NnNwNnWnW";  
137                 _code39Map['8'] = "WnNwNnWnN";  
138                 _code39Map['9'] = "NnWwNnWnN";  
139                                               
140                 _code39Map['A'] = "WnNnNwNnW";  
141                 _code39Map['B'] = "NnWnNwNnW";  
142                 _code39Map['C'] = "WnWnNwNnN";  
143                 _code39Map['D'] = "NnNnWwNnW";  
144                 _code39Map['E'] = "WnNnWwNnN";  
145                 _code39Map['F'] = "NnWnWwNnN";  
146                 _code39Map['G'] = "NnNnNwWnW";  
147                 _code39Map['H'] = "WnNnNwWnN";  
148                 _code39Map['I'] = "NnWnNwWnN";  
149                 _code39Map['J'] = "NnNnWwWnN";  
150                 _code39Map['K'] = "WnNnNnNwW";  
151                 _code39Map['L'] = "NnWnNnNwW";  
152                 _code39Map['M'] = "WnWnNnNwN";  
153                 _code39Map['N'] = "NnNnWnNwW";  
154                 _code39Map['O'] = "WnNnWnNwN";  
155                 _code39Map['P'] = "NnWnWnNwN";  
156                 _code39Map['Q'] = "NnNnNnWwW";  
157                 _code39Map['R'] = "WnNnNnWwN";  
158                 _code39Map['S'] = "NnWnNnWwN";  
159                 _code39Map['T'] = "NnNnWnWwN";  
160                 _code39Map['U'] = "WwNnNnNnW";  
161                 _code39Map['V'] = "NwWnNnNnW";  
162                 _code39Map['W'] = "WwWnNnNnN";  
163                 _code39Map['X'] = "NwNnWnNnW";  
164                 _code39Map['Y'] = "WwNnWnNnN";  
165                 _code39Map['Z'] = "NwWnWnNnN";  
166                                               
167                 _code39Map['-'] = "NwNnNnWnW";  
168                 _code39Map['.'] = "NwNnNnWnW";  
169                 _code39Map[' '] = "NwWnNnWnN";  
170                 _code39Map['$'] = "NwNwNwNnN";  
171                 _code39Map['/'] = "NwNwNnNwN";  
172                 _code39Map['+'] = "NwNnNwNwN";  
173                 _code39Map['%'] = "NnNwNwNwN";  
174                                               
175                 _code39Map['*'] = "NwNnWnWnN";  
176             }  
177         }  
178     }  

各字符对应编码中，W表示黑色宽条，w表示白色宽条，N表示黑色窄条，n表示白色窄条。需要注意的是，Code 39的相邻字符间需要有一个白色窄条用于分隔。

 

这个Demo还欠缺Code 39中校验码的处理（通常不需要），如果有需要的话，可以在此基础上补充，相信并不是困难的工作。

原文同步发布于我的个人博客