How to assign data in telerik report dynamically from c#?

Question

I have designed the report trdp file using the designer and added web service as data source. My plan is, when the report will be requested, instead of the web source, I want to pull the data using linq and want to inject that data in the report data source and want to pass it through the report processor. What I have done is: ``

        var rng = new Random();
        var datas = Enumerable.Range(1, 100).Select(index => new WeatherForecast
            {
                Category = Summaries[rng.Next(Summaries.Length)],
                Date = DateTime.Now.AddDays(index),
                TemperatureC = 1
            }).ToList();

        DataTable dataTable = Newtonsoft.Json.JsonConvert.DeserializeObject<DataTable>(Newtonsoft.Json.JsonConvert.SerializeObject(datas));
        Telerik.Reporting.Report report = null;
        using (var sourceStream = System.IO.File.OpenRead("Reports\\DemoReport.trdp"))
        {
            var reportPackager = new ReportPackager();
            report = (Report)reportPackager.UnpackageDocument(sourceStream);
            var dtsrc = new ObjectDataSource();
            dtsrc.DataSource = dataTable;
            report.DataSource = dtsrc;
        }
        

        Telerik.Reporting.Processing.ReportProcessor reportProcessor = new Telerik.Reporting.Processing.ReportProcessor();
        System.Collections.Hashtable deviceInfo = new System.Collections.Hashtable();
        Telerik.Reporting.Processing.RenderingResult result = reportProcessor.RenderReport("PDF", report, deviceInfo);

        var fileName = "adreport.pdf";
        using (FileStream fs = new FileStream(fileName, FileMode.Create))
        {
            fs.Write(result.DocumentBytes, 0, result.DocumentBytes.Length);
        }
        return Ok();

``

This generates the report but instead of a few pages, the generated pdf report contains a few hundreds of page with the same data repeatedly which is unusual. Can anyone explain why this is happening.

Answer 1

I am going to answer this question with as details as possible. For telerik reporting with angular and dynamically data assignment from backend code,follow the steps:-

1. Design the report template from Report designer
2. Place the templace in c# folter
3. Include report viewer in angular project
4. When report viewer will request for the report, handle it using the CustomReportResolver Sample code is provided below.

Angular

<tr-viewer #viewer1 
    [containerStyle]="viewerContainerStyle"
    [serviceUrl]="'https://localhost:5001/api/reports/'"
    [reportSource]="{
        report: 'DemoListReport.trdp',
        parameters:
        {

        }
    }"
    [viewMode]="'INTERACTIVE'"
    [scaleMode]="'SPECIFIC'"
    [scale]="1.0"
    [ready]="ready"
    [viewerToolTipOpening]="viewerToolTipOpening"
    [enableAccessibility]="false">
</tr-viewer>
<button (click)="viewer1.refreshReport()">Refresh</button>
<button (click)="viewer1.commands.print.exec()">Print</button>

.NET Core 3.1
Startup.cs

 services.TryAddScoped<IReportSourceResolver, CustomReportResolver>();
            // Configure dependencies for ReportsController.
            services.TryAddSingleton<IReportServiceConfiguration>(sp =>
                new ReportServiceConfiguration
                {
                    // The default ReportingEngineConfiguration will be initialized from appsettings.json or appsettings.{EnvironmentName}.json:
                        ReportingEngineConfiguration = sp.GetService<IConfiguration>(),
                        // In case the ReportingEngineConfiguration needs to be loaded from a specific configuration file, use the approach below:
                        // ReportingEngineConfiguration = ResolveSpecificReportingConfiguration(sp.GetService<IHostingEnvironment>()),
                        HostAppId = "Html5DemoAppCore",
                        Storage = new Telerik.Reporting.Cache.File.FileStorage(),
                        ReportSourceResolver = new CustomReportResolver()
                });

CustomReportResolver.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Telerik.Reporting;
using Telerik.Reporting.Services;
using Telerik.Reporting.Services.Engine;

namespace MyProject.API.Controllers
{
    public class CustomReportResolver: IReportSourceResolver
    {
        private static readonly string[] Summaries = new[]
        {
            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
        };
        

        public ReportSource Resolve(string report, OperationOrigin operationOrigin, IDictionary<string, object> currentParameterValues)
        {
            //data
            var rng = new Random();
            var datas = Enumerable.Range(1, 500).Select(index => new WeatherForecast
            {
                Category = Summaries[rng.Next(Summaries.Length)],
                Date = DateTime.Now.AddDays(index),
                TemperatureC = 1
            }).ToList();
            
            

            var reportPackager = new ReportPackager();
            Report reportt = null;
            using (var sourceStream = System.IO.File.OpenRead($"Reports\\{report}"))
            {
                reportt = (Report)reportPackager.UnpackageDocument(sourceStream);
            }

            DetailSection detail = (DetailSection)reportt.Items["detailSection1"];
            Table table = (Table)detail.Items["table1"];
            table.DataSource = datas.Take(5);


            Graph graph = (Graph)detail.Items["graph1"];
            graph.DataSource = datas;


            InstanceReportSource instanceReportSource = new InstanceReportSource();
            instanceReportSource.ReportDocument = reportt;

            return instanceReportSource;
        }
    }
}

Here datas will pass your data to the report. Hopefully this will help others later.