Ext.Net 1.2.0_演示 Ext.Net+Barcode 封装条形码控件

本文内容

• 概述
• 演示利用 Ext.Net + Barcode 封装条形码控件
• 运行结果
• 修改记录

概述

最近项目需要条形码，因为已经为每个业务都创建了编码，只要把编码生成相应的条形码即可。再者，不想在相应的表添加一个字段，既要保存编码，又要保存编码对应的条形码，保存其二进制数据，用的时候再生成条形码（图片）。

需要的时候再生成也可以。而且在页面显示图片，要么生成临时的条形码图片，用完再删；要么向客户端直接发送二进制流，并设置 HTTP 头 content-type="image/jpeg"。第一个方法有点麻烦；而第二个方法，打印报表怎么办？报表可很多来自不同表不同字段的数据等等。

那就把条形码搞成一个控件吧，反正浏览器是可以打印的。

本文演示如何利用 Ext.Net.Panel 和 Barcode 项目创建条形码。封装后如下所示：

<cc1:MyBarcode ID="MyBarcode1" runat="server" CustomBarCodeType="CODE39" CustomData="D012659834"
    Title="CODE39 条形码">
</cc1:MyBarcode>

其中，

• MyBarcode 控件为自定义条形码控件；
• CustomBarCodeType 属性是条形码类型；
• CustomData 属性是要生成条形码的字符串。

演示利用 Ext.Net + Barcode 封装条形码控件

解决方案结构

 

自定义 MyBarcode UI

using System;
using Ext.Net;
using System.ComponentModel;

namespace MyExtNet.Control
{
    public partial class MyBarcode
    {

        [DefaultValue("")]
        [Description("条形码类型)")]
        public string CustomBarCodeType
        {
            get
            {
                return (string)this.ViewState["CustomBarCodeType"] ?? "";
            }
            set { this.ViewState["CustomBarCodeType"] = value; }
        }
        [DefaultValue("")]
        [Description("数据")]
        public string CustomData
        {
            get
            {
                return (string)this.ViewState["CustomData"] ?? "";
            }
            set { this.ViewState["CustomData"] = value; }
        }

        public MyBarcode()
        {
            this.AnimCollapse = false;
            this.AutoDataBind = false;
        }
        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender(e);
            if (this.CustomBarCodeType.Length <= 0)
                throw new NullReferenceException("Invalid Param.");
            if (this.Width.IsEmpty)
                this.Width = System.Web.UI.WebControls.Unit.Pixel(250);
            if (this.Height.IsEmpty)
                this.Height = System.Web.UI.WebControls.Unit.Pixel(80);

            this.AutoLoad.Url = "~/BarcodeHandler.ashx";
            this.AutoLoad.Mode = Ext.Net.LoadMode.IFrame;
            this.AutoLoad.Method = Ext.Net.HttpMethod.GET;
            this.AutoLoad.Params.Add(new Parameter() { Name = "Data", Value = this.CustomData, Mode = Ext.Net.ParameterMode.Value });
            this.AutoLoad.Params.Add(new Parameter() { Name = "BarCodeType", Value = this.CustomBarCodeType, Mode = Ext.Net.ParameterMode.Value });
            this.AutoLoad.Params.Add(new Parameter() { Name = "Width", Value = this.Width.Value.ToString(), Mode = Ext.Net.ParameterMode.Value });
            this.AutoLoad.Params.Add(new Parameter() { Name = "Height", Value = this.Height.Value.ToString(), Mode = Ext.Net.ParameterMode.Value });
        }
    }
}

 

自定义 MyBarcode Logic

using System;
using Ext.Net;
using System.Web;

namespace MyExtNet.Control
{
    public partial class MyBarcode : Ext.Net.Panel
    {
    }
}

说明

MyBarcode UI 和 MyBarcode Logic 是一个分部类 MyBarcode，对于自定义 WebControl 来说，将控件的 UI 部分和逻辑部分分别实现，很清晰。本例的 MyBarcode Logic 部分没内容。

自定义处理程序 BarcodeHandler.ashx

该处理程序根据指定字符串生成条形码，并发送给客户端。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace ExtNetBar
{
    /// <summary>
    /// $codebehindclassname$ 的摘要说明
    /// </summary>
    //[WebService(Namespace = "http://tempuri.org/")]
    //[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    public class BarcodeHandler : IHttpHandler
    {
        private ImageFormat _imageFormat = ImageFormat.Jpeg;
        HttpResponse _response;
        HttpRequest _request;
        string data;
        BarcodeLib.BarCodeType barCodeType;

        public void ProcessRequest(HttpContext context)
        {
            _response = context.Response;
            _request = context.Request;

            try
            {
                data = _request.QueryString["Data"].ToString();
                if (_request.QueryString["BarCodeType"].ToString().Length > 0)
                    barCodeType = (BarcodeLib.BarCodeType)Enum.Parse(typeof(BarcodeLib.BarCodeType), _request.QueryString["BarCodeType"].ToString());
                else
                    barCodeType = BarcodeLib.BarCodeType.CODE128;
                int width = (int)(Convert.ToDouble(_request.QueryString["Width"].ToString()));
                int height = (int)Convert.ToDouble(_request.QueryString["Height"].ToString());
                Bitmap bitMap = (Bitmap)BarcodeLib.Barcode.DoEncode(barCodeType, data, width, height);
                WriteImageToStream(bitMap);
            }
            catch (Exception ex)
            {
                WriteImageToStream(CreateErrorBitmap(ex.Message));
            }
        }
        private Bitmap CreateErrorBitmap(string errMessage)
        {
            int width = 300;
            int height = 100;

            Bitmap errBitmap = new Bitmap(width, height);

            Graphics g = Graphics.FromImage(errBitmap);

            StringFormat strFormat = new StringFormat();

            strFormat.Alignment = StringAlignment.Center;
            strFormat.LineAlignment = StringAlignment.Center;

            g.FillRectangle(Brushes.White, 0, 0, width, height);
            g.DrawRectangle(new Pen(Brushes.LightGray, 1), new Rectangle(0, 28, width - 1, height - 33));

            strFormat.Alignment = StringAlignment.Center;
            strFormat.LineAlignment = StringAlignment.Near;
            g.DrawString("Barcode Generator Error", new Font("Arial", 10, FontStyle.Bold), Brushes.Red, new Rectangle(0, 5, width, 15), strFormat);

            strFormat.Alignment = StringAlignment.Center;
            strFormat.LineAlignment = StringAlignment.Center;

            switch (errMessage)
            {
                case "Wrong character":
                    errMessage = "Input data contains unsupported characters - select another barcode type or correct your input data.";
                    break;
                case "Wrong number of input characters":
                    errMessage = "This barcode needs a specific number of input characters - correct your data.";
                    break;
                default:
                    break;
            }

            g.DrawString(errMessage, new Font("Arial", 10), Brushes.Red, new Rectangle(8, 28, width - 16, height - 35), strFormat);

            return errBitmap;
        }
        private void WriteImageToStream(Bitmap bitMap)
        {
            _response.ClearContent();
            _response.AddHeader("Content-type", "image/jpeg");
            bitMap.Save(_response.OutputStream, _imageFormat);
        }
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

创建页面

<%@ Page Language="C#" %>

<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<%@ Register Assembly="MyExtNet.Control" Namespace="MyExtNet.Control" TagPrefix="cc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

    <script runat="server">           protected void Page_Load(object sender, EventArgs e)         {             if (!X.IsAjaxRequest)             {                 this.MyBarcode6.CustomBarCodeType = "UPCA";                 this.MyBarcode6.CustomData = "101265983434";             }         }     </script>

</head>
<body>
    <form id="form1" runat="server">
    <ext:ResourceManager ID="ResourceManager1" runat="server">
    </ext:ResourceManager>
    <cc1:MyBarcode ID="MyBarcode1" runat="server" CustomBarCodeType="CODE39" CustomData="D012659834"
        Title="CODE39 条形码">
    </cc1:MyBarcode>
    <cc1:MyBarcode ID="MyBarcode2" runat="server" CustomBarCodeType="CODE93" CustomData="D012659834"
        Title=" CODE93 条形码">
    </cc1:MyBarcode>
    <cc1:MyBarcode ID="MyBarcode3" runat="server" CustomBarCodeType="Codabar" CustomData="A90126598D"
        Title=" Codabar 条形码">
    </cc1:MyBarcode>
    <cc1:MyBarcode ID="MyBarcode4" runat="server" CustomBarCodeType="ISBN" CustomData="1012659834"
        Title="ISBN 条形码">
    </cc1:MyBarcode>
    <cc1:MyBarcode ID="MyBarcode5" runat="server" CustomBarCodeType="UPCA" CustomData="101265983434"
        Title="UPCA 条形码">
    </cc1:MyBarcode>
    <cc1:MyBarcode ID="MyBarcode6" runat="server" Title="UPCA 条形码">
    </cc1:MyBarcode>
    </form>
</body>
</html>

其中，

ID 为 MyBarcode1，创建 CODE39 条形码；

ID 为 MyBarcode2，创建 CODE93 条形码；

ID 为 MyBarcode3，创建 Codebar 条形码；

ID 为 MyBarcode4，创建 ISBN 条形码；

ID 为 MyBarcode5，创建 UPCA 条形码，利用标记创建；

ID 为 MyBarcode6，创建 UPCA 条形码，后台创建。

运行结果

修改记录

• 第一次 2012-1-10 [UPDATE] 概述

下载 Demo