BarCode条形码基于C# GDI+ 的实现方法详解

条形码在生活中的应用非常广泛，具体的条形码知识大家自行百度，了解条形码知识对理解下面的代码是必要的。如果只是应用的话，直接拿去就可以用了。
废话不多说，上代码

public bitmap getcode39(string sourcecode)
         {
             int leftmargin = 5;
             int topmargin = 0;
             int thicklength = 2;
             int narrowlength = 1;
             int barcodeheight = 35;
             int intsourcelength = sourcecode.length;
             string strencode = "010010100"; //添加起始码“*”.
             var font = new system.drawing.font("segoe ui", 5);

             string alphabet = "0123456789abcdefghijklmnopqrstuvwxyz-. $/+%*";

             string[] code39 =
             {
                 /* 0 */ "000110100", 
                 /* 1 */ "100100001", 
                 /* 2 */ "001100001", 
                 /* 3 */ "101100000",
                 /* 4 */ "000110001", 
                 /* 5 */ "100110000", 
                 /* 6 */ "001110000", 
                 /* 7 */ "000100101",
                 /* 8 */ "100100100", 
                 /* 9 */ "001100100", 
                 /* a */ "100001001", 
                 /* b */ "001001001",
                 /* c */ "101001000", 
                 /* d */ "000011001", 
                 /* e */ "100011000", 
                 /* f */ "001011000",
                 /* g */ "000001101", 
                 /* h */ "100001100", 
                 /* i */ "001001100", 
                 /* j */ "000011100",
                 /* k */ "100000011", 
                 /* l */ "001000011", 
                 /* m */ "101000010", 
                 /* n */ "000010011",
                 /* o */ "100010010", 
                 /* p */ "001010010", 
                 /* q */ "000000111", 
                 /* r */ "100000110",
                 /* s */ "001000110", 
                 /* t */ "000010110", 
                 /* u */ "110000001", 
                 /* v */ "011000001",
                 /* w */ "111000000", 
                 /* x */ "010010001", 
                 /* y */ "110010000", 
                 /* z */ "011010000",
                 /* - */ "010000101", 
                 /* . */ "110000100", 
                 /*' '*/ "011000100",
                 /* $ */ "010101000",
                 /* / */ "010100010", 
                 /* + */ "010001010", 
                 /* % */ "000101010", 
                 /* * */ "010010100" 
             };
             sourcecode = sourcecode.toupper();

             bitmap objbitmap = new bitmap(
               ((thicklength * 3 + narrowlength * 7) * (intsourcelength + 2)) + (leftmargin * 2),
               barcodeheight + (topmargin * 2));
             graphics objgraphics = graphics.fromimage(objbitmap);

             objgraphics.fillrectangle(brushes.white, 0, 0, objbitmap.width, objbitmap.height);

             for (int i = 0; i < intsourcelength; i++)
             {
                 //非法字符校验
                 if (alphabet.indexof(sourcecode[i]) == -1 || sourcecode[i] == '*')
                 {
                     objgraphics.drawstring("invalid bar code",
                       systemfonts.defaultfont, brushes.red, leftmargin, topmargin);
                     return objbitmap;
                 }
                 //编码
                 strencode = string.format("{0}0{1}", strencode,
                  code39[alphabet.indexof(sourcecode[i])]);
             }

             strencode = string.format("{0}0010010100", strencode); //添加结束码“*”

             int intencodelength = strencode.length;
             int intbarwidth;

             for (int i = 0; i < intencodelength; i++) //绘制 code39 barcode
             {
                 intbarwidth = strencode[i] == '1' ? thicklength : narrowlength;
                 objgraphics.fillrectangle(i % 2 == 0 ? brushes.black : brushes.white,
                  leftmargin, topmargin, intbarwidth, barcodeheight);
                 leftmargin += intbarwidth;
             }

             //绘制 明码
             sizef sizef = objgraphics.measurestring(sourcecode, font);
             float x=(objbitmap.width - sizef.width) / 2;
             float y = objbitmap.height - sizef.height;
             objgraphics.fillrectangle(brushes.white, x, y, sizef.width, sizef.height);
             objgraphics.drawstring(sourcecode, font, brushes.black, x, y);

             return objbitmap;
         }

新建一个winform程序拖一个picturebox控件，然后把方法返回的图片绑到picturebox上，就可以看到结果了。

以上代码需要引用 system.drawing 命名空间。

顺带提一句，还有一种最简单的办法就是下载条形码字体，然后输出的时候设定字体为条形码字体，显示的就是条形码了。不过你不能要求每个客户机都装这种字体。这个是个明显的缺陷,所以不推荐使用这种方法。