Add Report Storage to ASP.NET Core Application

• Jan 18, 2022
• 7 minutes to read

Design Considerations

The End-User Report Designer for Web requires a report storage to operate correctly. The table below lists the functions that will be unavailable to users if a report storage is not registered in your application.

Commands/Functions	With Storage	Without Storage
Edit the report supplied from code
Save
Save As
Open
New
New via Wizard
Manage Subreports

As shown in this table, users can edit a report but cannot use multiple stored report definitions. If these limitations are suitable for your application, you can work with reports without a custom storage. Otherwise, create and register a report storage.

Create and Register a Report Storage

Follow the steps below to create a server-side storage for web reports.

Create a Report Storage Class

Create a class that inherits from the abstract ReportStorageWebExtension class. You can write a new class or use the DevExpress Project Wizard.

If you use the DevExpress Project Wizard, leave the Add Report Storage option checked. The wizard generates and registers a file system report storage. You can specify the class name in the Report Storage Name field:

DevExpress Project Templates always create and register a file-based report storage if you create a project from the console (CLI).

Important

The template generates a sample storage (a ReportStorageWebExtension descendant) for demonstration purposes only. Create your own implementation for use in production.

Override Class Methods

You need to implement the following methods:

Method	Description
IsValidUrl	Determines whether the URL passed to the current report storage is valid. Implement your own logic to prohibit URLs that contain spaces or other specific characters. Return true if no validation is required.
CanSetData	Determines whether a report with the specified URL can be saved. Add custom logic that returns false for reports that should be read-only. Return true if no valdation is required. This method is called only for valid URLs (if the IsValidUrl method returns true).
SetData	Saves the specified report to the report storage with the specified URL (i.e., it saves existing reports only).
SetNewData	Allows you to validate and correct the specified URL. This method also allows you to return the resulting URL and to save your report to a storage. The method is called only for new reports.
GetData	Uses a specified URL to return report layout data stored within a report storage medium. This method is called if the IsValidUrl method returns true. You can use the GetData method to process report parameters sent from the client if the parameters are included in the report URL’s query string.
GetUrls	Returns a dictionary that contains the report URLs and display names.

In the following table, select a column that describes the user action. Then, read the entries top to bottom for information on the order of method calls. The table also indicates the moments when the designer invokes Open Report and Save Report dialogs.

Method/Command	Save As	Save	Open
GetUrls
(Open Report dialog)
IsValidUrl
CanSetData
(Save Report dialog)
SetNewData
SetData
GetData
GetUrls

For more information on how the reports and documents are stored, review the following help topic: Store Report Layouts and Documents.

Register a Storage

Skip this step if you used a project template to generate your report storage class. If you declared a ReportStorageWebExtension descendant manually, register your web report storage medium as a service in the ConfigureServices method at application startup:

Startup.cs

using DevExpress.XtraReports.Web.Extensions;
//... 

    public class Startup {
        // ...

        public void ConfigureServices(IServiceCollection services) {
            // ...
            services.AddDevExpressControls();
            // Register the storage after the AddDevExpressControls method call.
            services.AddScoped<ReportStorageWebExtension, CustomReportStorageWebExtension>(); 
            // ...  
        }
    // ...
    }    

Important

Register the ReportStorageWebExtension after the AddDevExpressControls method.

Report Storage Examples

For a code example, create a new Web project from the DevExpress Visual Studio template and review the code for the CustomReportStorageWebExtension class in the Services folder.

For more information review the following help topic: Create an ASP.NET Core Application with a Report Designer

• How to store reports in a SQLite database:

  Show code

  CustomReportStorageWebExtension.cs

  using System.Collections.Generic;
  using System.IO;
  using System.Linq;
  using DevExpress.XtraReports.UI;
  using AspNetCoreSample.PredefinedReports;
  using AspNetCoreSample.Data;
  
  namespace AspNetCoreSample.Services
  {
      public class CustomReportStorageWebExtension : 
          DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension
      {
          protected ReportDbContext DbContext { get; set; }
          public CustomReportStorageWebExtension(ReportDbContext dbContext) {
              this.DbContext = dbContext;
          }
  
          public override bool CanSetData(string url) {
              // Determines whether a report with the specified URL can be saved.
              // Add custom logic that returns **false** for reports that should be read-only.
              // Return **true** if no valdation is required.
              // This method is called only for valid URLs (if the **IsValidUrl** method returns **true**).
  
              return true;
          }
  
          public override bool IsValidUrl(string url) {
              // Determines whether the URL passed to the current report storage is valid.
              // Implement your own logic to prohibit URLs that contain spaces or other specific characters.
              // Return **true** if no validation is required.
  
              return true;
          }
  
          public override byte[] GetData(string url) {
              // Uses a specified URL to return report layout data stored within a report storage medium.
              // This method is called if the **IsValidUrl** method returns **true**.
              // You can use the **GetData** method to process report parameters sent from the client
              // if the parameters are included in the report URL's query string.
              var reportData = DbContext.Reports.FirstOrDefault(x => x.Name == url);
              if(reportData != null)
                  return reportData.LayoutData;
  
              if(ReportsFactory.Reports.ContainsKey(url)) {
                  using var ms = new MemoryStream();
                  using XtraReport report = ReportsFactory.Reports[url]();
                  report.SaveLayoutToXml(ms);
                  return ms.ToArray();
              }
              throw new DevExpress.XtraReports.Web.ClientControls.FaultException(
                  string.Format("Could not find report '{0}'.", url));
          }
  
          public override Dictionary<string, string> GetUrls() {
              // Returns a dictionary that contains the report names (URLs) and display names. 
              // The Report Designer uses this method to populate the Open Report and Save Report dialogs.
  
              return DbContext.Reports
                  .ToList()
                  .Select(x => x.Name)
                  .Union(ReportsFactory.Reports.Select(x => x.Key))
                  .ToDictionary<string, string>(x => x);
          }
  
          public override void SetData(XtraReport report, string url) {
              // Saves the specified report to the report storage with the specified name
              // (saves existing reports only). 
              using var stream = new MemoryStream(); report.SaveLayoutToXml(stream);
              var reportData = DbContext.Reports.FirstOrDefault(x => x.Name == url);
              if(reportData == null) {
                  DbContext.Reports.Add(new ReportItem { Name = url, LayoutData = stream.ToArray() });
              } else {
                  reportData.LayoutData = stream.ToArray();
              }
              DbContext.SaveChanges();
          }
  
          public override string SetNewData(XtraReport report, string defaultUrl) {
              // Allows you to validate and correct the specified name (URL).
              // This method also allows you to return the resulting name (URL),
              // and to save your report to a storage. The method is called only for new reports.
              SetData(report, defaultUrl);
              return defaultUrl;
          }
      }
  }
  

  ReportDbContext.cs

  using System.Linq;
  using Microsoft.EntityFrameworkCore;
  
  namespace AspNetCoreSample.Data {
      public class SqlDataConnectionDescription : DataConnection { }
      public class JsonDataConnectionDescription : DataConnection { }
      public abstract class DataConnection {
          public int Id { get; set; }
          public string Name { get; set; }
          public string DisplayName { get; set; }
          public string ConnectionString { get; set; }
      }
  
      public class ReportItem {
          public int Id { get; set; }
          public string Name { get; set; }
          public string DisplayName { get; set; }
          public byte[] LayoutData { get; set; }
      }
  
      public class ReportDbContext : DbContext {
          public DbSet<JsonDataConnectionDescription> JsonDataConnections { get; set; }
          public DbSet<SqlDataConnectionDescription> SqlDataConnections { get; set; }
          public DbSet<ReportItem> Reports { get; set; }
          public ReportDbContext(DbContextOptions<ReportDbContext> options) : base(options) {
          }
          public void InitializeDatabase() {
              Database.EnsureCreated();
  
              var nwindJsonDataConnectionName = "NWindProductsJson";
              if(!JsonDataConnections.Any(x => x.Name == nwindJsonDataConnectionName)) {
                  var newData = new JsonDataConnectionDescription {
                      Name = nwindJsonDataConnectionName,
                      DisplayName = "Northwind Products (JSON)",
                      ConnectionString = "Uri=Data/nwind.json"
                  };
                  JsonDataConnections.Add(newData);
              }
  
  
              var nwindSqlDataConnectionName = "NWindConnectionString";
              if(!SqlDataConnections.Any(x => x.Name == nwindSqlDataConnectionName)) {
                  var newData = new SqlDataConnectionDescription {
                      Name = nwindSqlDataConnectionName,
                      DisplayName = "Northwind Data Connection",
                      ConnectionString = "XpoProvider=SQLite;Data Source=|DataDirectory|/Data/nwind.db"
                  };
                  SqlDataConnections.Add(newData);
              }
  
              var reportsDataConnectionName = "ReportsDataSqlite";
              if(!SqlDataConnections.Any(x => x.Name == reportsDataConnectionName)) {
                  var newData = new SqlDataConnectionDescription {
                      Name = reportsDataConnectionName,
                      DisplayName = "Reports Data (Demo)",
                      ConnectionString = "XpoProvider=SQLite;Data Source=|DataDirectory|/Data/reportsData.db"
                  };
                  SqlDataConnections.Add(newData);
              }
              SaveChanges();
          }
      }
  }
  

• How to store reports in Azure Cosmos DB:

  Review the following blog post: ASP.NET Core Reporting - Store Reports within a Database Using Azure Cosmos DB.