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如何使用Ajax从FastReport Web API获取报表

来源:   发布时间:2018-01-16   浏览:202次

在文章“如何在ASP.NET Web API中使用FastReport.Net”中,我们已经讨论了如何创建一个用于生成报表的Web服务。然后我们会收到报表的链接,现在我们来看看如何获​​取报表并使用ajax脚本显示它。

让我提醒你一下,我们的服务可以返回以这些格式之一导出的报表:PDF、HTML、PNG。我们将以HTML格式接收报表,并使用ajax脚本将其显示在网页上。

我们接下来讲解一下从头开始创建WebApi应用程序的过程。首先,创建一个ASP.Net应用程序,WebAPI。选择空模板并勾选选项:MVC和WebApi。

如何使用Ajax从FastReport Web API获取报表

在项目引用中,添加FastReport.dll库。

我们继续创建一个数据模型。现在Model文件夹是空的。点击右键并选择“Add”,“Class”。

将其命名为Reports.cs。添加两个字段:Id和ReportName:

namespace FastReportWebApiDemo.Models
{
 public class Reports
 {
 // Report ID
 public int Id { get; set; }
 // Report File Name
 public string ReportName { get; set; }
 }
}

你需要将报表模板和数据库文件放在App_Data文件夹中。在我们的例子中,我们把这两个报表放进去:“Simple List.frx”和“Barcode.frx”;

现在,在Controllers文件夹中,添加控制器ReportsController。它将包含应用程序的所有逻辑。我们使用Controllers文件夹的上下文菜单执行此操作。选择“添加” - >“控制器“:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using FastReport;
using FastReport.Export.Image;
using FastReport.Export.Html;
using FastReport.Export.Pdf;
using FastReport.Utils;
using FastReportWebApiDemo.Models;
using System.Web.Hosting;
using System.Data;
using System.IO;
using System.Net.Http.Headers;
 
namespace FastReportWebApiDemo.Controllers
{
// Transfer class with parameters for requesting a report
 public class ReportQuery
 {
 // Format of resulting report: png, pdf, html
 public string Format { get; set; }
 // Value of "Parameter" variable in report
 public string Parameter { get; set; }
 // Enable Inline preview in browser (generates "inline" or "attachment")
 public bool Inline { get; set; }
 }
 
 public class ReportsController : ApiController
 { //Reports list
 Reports[] reportItems = new Reports[]
 {
 new Reports { Id = 1, ReportName = "Simple List.frx" },
 new Reports { Id = 2, ReportName = "Barcode.frx" }
 };
 
 // Get list of reports
 public IEnumerable<Reports> GetAllReports()
 {
 return reportItems;
 }
 
 // Get report by ID from request
 public HttpResponseMessage GetReportById(int id, [FromUri] ReportQuery query)
 {
 // Find report
 Reports reportItem = reportItems.FirstOrDefault((p) => p.Id == id);
 if (reportItem != null)
 {
 string reportPath = HostingEnvironment.MapPath("~/App_Data/" + reportItem.ReportName);
 string dataPath = HostingEnvironment.MapPath("~/App_Data/nwind-employees.xml");
 MemoryStream stream = new MemoryStream();
 try
 {
 using (DataSet dataSet = new DataSet())
 {
// Fill the data source with the data
 dataSet.ReadXml(dataPath);
// Enable FastReport web mode
 Config.WebMode = true;
 using (Report report = new Report())
 {
 report.Load(reportPath); // Load the report
 report.RegisterData(dataSet, "NorthWind"); // Register the data in the report
 if (query.Parameter != null)
 {
 report.SetParameterValue("Parameter", query.Parameter); // Set the value of the parameter in the report. The very meaning we take from the URL
 }
 
 // Two phases of preparation to exclude the display of any dialogs
 report.PreparePhase1();
 report.PreparePhase2();
 
 if (query.Format == "pdf")
 {
// Export the report to PDF
 PDFExport pdf = new PDFExport();
// We use the stream to store the report so that we do not produce files
 report.Export(pdf, stream);
 }
 else if (query.Format == "html")
 {
// Export the report to HTML
 HTMLExport html = new HTMLExport();
 html.SinglePage = true;
 html.Navigator = false;
 html.EmbedPictures = true;
 report.Export(html, stream);
 }
 else if (query.Format == "png")
 {
// Export the report to PNG
 using (ImageExport img = new ImageExport())
 {
 img.ImageFormat = ImageExportFormat.Png;
 img.SeparateFiles = false;
 img.ResolutionX = 96;
 img.ResolutionY = 96;
 report.Export(img, stream);
 query.Format = "png";
 }
 }
 else
 {
 WebReport webReport = new WebReport();// Create a report object
 webReport.Report.Load(reportPath); // Load the report
 webReport.Report.RegisterData(dataSet, "NorthWind"); // Register the data source in the report
 if (query.Parameter != null)
 {
 webReport.Report.SetParameterValue("Parameter", query.Parameter); // Set the value of the report parameter
 }
 // inline registration of FastReport javascript
 webReport.InlineRegistration = true; // Allows you to register scripts and styles in the body of the html-page instead of placing them in the title
 webReport.Width = Unit.Percentage(100);
 webReport.Height = Unit.Percentage(100);
 // get control
 HtmlString reportHtml = webReport.GetHtml(); // load the report into HTML
 byte[] streamArray = Encoding.UTF8.GetBytes(reportHtml.ToString());
 stream.Write(streamArray, 0, streamArray.Length); // Write the report to the stream
 } 
}
 }
// create the resulting variable
 HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK)
 {
 Content = new ByteArrayContent(stream.ToArray())
 };
 
 stream.Dispose();
 
 result.Content.Headers.ContentDisposition =
 new System.Net.Http.Headers.ContentDispositionHeaderValue(query.Inline ? "inline" : "attachment")
 {
// Set the file extension depending on the type of export
 FileName = String.Concat(Path.GetFileNameWithoutExtension(reportPath), ".", query.Format)
 };
// Define the content type for the browser
result.Content.Headers.ContentType =
 new MediaTypeHeaderValue("application/" + query.Format);
 return result;
 }
// Handle Exceptions
 catch
 {
 return new HttpResponseMessage(HttpStatusCode.InternalServerError);
 }
 }
 else
 return new HttpResponseMessage(HttpStatusCode.NotFound);
 }
 }
}

在ReportsController类中,我们创建了一个报表数组和两个方法。名称和报表标识符在数组中定义。GetAllReports () 方法返回可用报表的列表。第二种方法 GetReportById (int id, [FromUri] ReportQuery query) 通过标识符返回一个报表。从查询属性中,我们可以得到参数格式、内联和参数。这三者分别决定:报表的导出格式,报表是否会直接在浏览器中打开,传递给报表的参数的值。特别有趣的是 webReport.GetHtml () 方法,它可以让你获得报表的HTML视图。这就是我们使用ajax在页面上显示的内容。

在Web.config文件中,你需要添加两个处理句柄:

<handlers>
… 
<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
 <add name="FastReportHandler" path="FastReport.Export.axd" verb="*" type="FastReport.Web.Handlers.WebExport" />
…
</handlers>

现在添加网页。在项目上点击右键并选择Add-> HTML Page。

一般我们习惯将起始页命名为Index。将以下代码添加到页面中:

<!DOCTYPE html>
<html>
<head>
 <title></title>
 <meta charset="utf-8" />
 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
</head>
<body>
 <script type="text/javascript" language="javascript">
 function call() {
 var msg = $('#formx').serialize();
 $.ajax({ 
 type: 'GET',// Type
 url: 'http://localhost:58005/api/reports/1', // We receive a file from Rest service
 cache: false,// Caching
 timeout: 30000,// Timeout
 data: msg,
 success: function (data) {// The function will work if the data is successfully received
 $('#results').html(data);// We display the data in the form },
 beforeSend: function (data) {// The function is activated during the waiting period of data
 $('#results').html('<p> Waiting for data...</p>');
 },
 dataType: "html", // Data type 
 error: function (data) {// Function will work if an error occurs
 $('#results').html('<p> Failed to load report</p>');
 }
 });
 }
 </script>
<form method="GET" id="formx" action="javascript:void(null);" onsubmit="call()">
 <input value="Загрузить" type="submit">
 </form>
 <div id="results" typeof="submit"></div><!-- Here the result will be displayed-->
</body>
</html>

从代码中可以看到,我们只是通过从服务链接请求来加载HTML报表文件。

从文件夹App_Start打开文件WebApiConfig.cs。为Index页面添加一个MapHttpRoute:

public static void Register(HttpConfiguration config)
 {
 // Web API configuration and services
 // Web API routes
 config.MapHttpAttributeRoutes();
 config.Routes.MapHttpRoute(
 name: "Index",
 routeTemplate: "{id}.html",
 defaults: new { id = "index" }
 );
 
 config.Routes.MapHttpRoute(
 name: "DefaultApi",
 routeTemplate: "api/{controller}/{id}",
 defaults: new { id = RouteParameter.Optional }
 );
 }

在同一个文件夹中,找到RouteConfig.cs文件。它可以被删除。

打开文件Global.asax。删除该行: 

RouteConfig.RegisterRoutes(RouteTable.Routes); 

现在路由只能通过WebApiConfig来完成。

运行该应用程序,然后单击“下载”按钮:

如何使用Ajax从FastReport Web API获取报表

就这样,我们收到了报表。

从上面的例子可以清楚的看出,使用Ajax进行报表处理是非常简单的。


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