Add a Report Storage

• Apr 10, 2023
• 11 minutes to read

Design Considerations

When you add the End-User Report Designer for Web to your project, it operates without a report storage. You should consider whether your application requires a custom report storage and think ahead about the implementation details. The table below lists the functions that will be unavailable to end users without a report storage registered in your application.

Commands/Functions	With Storage	Without Storage
Save
Save As
Open
New
New via Wizard
Manage Subreports

As you can see in the table above, you can edit a report, but cannot manipulate multiple stored report definitions. If these limitations are suitable for your application, you can work with reports without a custom storage.

Operation without a Report Storage

Initially the Report Designer operates without the New via Wizard, Open and Save As menu commands. This operation mode also doesn’t allow end users to manage Subreports - a double click on a subreport has no effect.

The client-side API methods that allows you to load and save a report do not work without a report storage. Use the following server-side API to load a report to the End-User Designer and save user changes:

API	Description
ASPxReportDesigner.OpenReport	Load a report layout into the Designer.
ASPxReportDesigner.OpenReportXmlLayout(Byte[])	Load a report layout from the byte array of XML data (REPX format) into the Designer.
ASPxReportDesigner.SaveReportLayout	Fires when end-users invoke the Save command in the End-User Designer. The event contains a ReportLayout parameter that stores the current layout as a byte array.

Operation with a Report Storage

To save and load reports, the DevExpress Web Report Designer requires access to a storage medium (a database, file system, cloud service, etc.). To add a server-side report storage medium to your web application, you must create and register a custom report storage class.

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 use one of the following methods:

• 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:

  

  Important

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

• Click Add New Item in the Visual Studio Designer and select the DevExpress v20.2 Report Storage Web item in the Reporting section:

  

• You can click the Report Designer’s smart tag and select Add report storage.

  

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, item template, or smart tag to generate your report storage class. If you declared a ReportStorageWebExtension descendant manually, create a new instance and pass it to the static ReportStorageWebExtension.RegisterExtensionGlobal method at application startup:

Global.asax.cs

public class Global : System.Web.HttpApplication {
    protected void Application_Start(object sender, EventArgs e) {
        // ...
        DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension.RegisterExtensionGlobal(new CustomReportStorageWebExtension()); 
    }
    // ...
}

Global.asax.vb

Public Class [Global]
    Inherits System.Web.HttpApplication
    Protected Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
    ' ...
        DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension.RegisterExtensionGlobal(New CustomReportStorageWebExtension())
    End Sub
    ' ...
End Class

Report Storage Examples

• How to store reports in a Microsoft SQL Server database:

  Note

  The complete sample project is available in the following DevExpress Examples repository on GitHub: How to Integrate Web Report Designer in a Web Application.

  Show code

  CustomReportStorageWebExtension.cs

  using DevExpress.XtraReports.UI;
  using System;
  using System.Collections.Generic;
  using System.Data;
  using System.Data.SqlClient;
  using System.IO;
  using System.Linq;
  
  namespace SimpleWebReportCatalog
  {
      public class CustomReportStorageWebExtension : 
          DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension
      {
          private DataTable reportsTable = new DataTable();
          private SqlDataAdapter reportsTableAdapter;
          string connectionString = "Data Source=localhost;Initial Catalog=Reports;Integrated Security=True";
          public CustomReportStorageWebExtension()
          {
              reportsTableAdapter = 
                  new SqlDataAdapter("Select * from ReportLayout", new SqlConnection(connectionString));
              SqlCommandBuilder builder = new SqlCommandBuilder(reportsTableAdapter);
              reportsTableAdapter.InsertCommand = builder.GetInsertCommand();
              reportsTableAdapter.UpdateCommand = builder.GetUpdateCommand();
              reportsTableAdapter.DeleteCommand = builder.GetDeleteCommand();
              reportsTableAdapter.Fill(reportsTable);
              DataColumn[] keyColumns = new DataColumn[1];
              keyColumns[0] = reportsTable.Columns[0];
              reportsTable.PrimaryKey = keyColumns;
          }
          public override bool CanSetData(string url)
          {
              return true;
          }
          public override byte[] GetData(string url)
          {
              // Get the report data from the storage.
              DataRow row = reportsTable.Rows.Find(int.Parse(url));
              if (row == null) return null;
  
              byte[] reportData = (Byte[])row["LayoutData"];
              return reportData;
          }
          public override Dictionary<string, string> GetUrls()
          {
              reportsTable.Clear();
              reportsTableAdapter.Fill(reportsTable);
              // Get URLs and display names for all reports available in the storage.
              var v = reportsTable.AsEnumerable()
                    .ToDictionary<DataRow, string, string>(dataRow => ((Int32)dataRow["ReportId"]).ToString(),
                                                           dataRow => (string)dataRow["DisplayName"]);
              return v;
          }
          public override bool IsValidUrl(string url)
          {
              return true;
          }
          public override void SetData(XtraReport report, string url)
          {
              // Write a report to the storage under the specified URL.
              DataRow row = reportsTable.Rows.Find(int.Parse(url));
              if (row != null)
              {
                  using (MemoryStream ms = new MemoryStream())
                  {
                      report.SaveLayoutToXml(ms);
                      row["LayoutData"] = ms.GetBuffer();
                  }
                  reportsTableAdapter.Update(reportsTable);
              }
          }
          public override string SetNewData(XtraReport report, string defaultUrl)
          {
              // Save a report to the storage with a new URL. 
              // The defaultUrl parameter is the report name that the user specifies.
              DataRow row = reportsTable.NewRow();
              row["ReportId"] = 0;
              row["DisplayName"] = defaultUrl;
              using (MemoryStream ms = new MemoryStream())
              {
                  report.SaveLayoutToXml(ms);
                  row["LayoutData"] = ms.GetBuffer();
              }
              reportsTable.Rows.Add(row);
              reportsTableAdapter.Update(reportsTable);
              // Refill the dataset to obtain the actual value of the new row's autoincrement key field.
              reportsTable.Clear();
              reportsTableAdapter.Fill(reportsTable);
              return reportsTable.AsEnumerable().
                  FirstOrDefault(x => x["DisplayName"].ToString() == defaultUrl)["ReportId"].ToString();
          }
      }
  }
  

  CustomReportStorageWebExtension.vb

  Imports System
  Imports System.Collections.Generic
  Imports System.Data
  Imports System.IO
  Imports System.Linq
  Imports DevExpress.XtraReports.UI
  Imports SimpleWebReportCatalog.CatalogDataTableAdapters
  ' ...
  
  Namespace SimpleWebReportCatalog
      Public Class CustomReportStorageWebExtension
          Inherits DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension
  
          Private catalogDataSet As CatalogData
          Private reportsTable As DataTable
          Private reportsTableAdapter As ReportsTableAdapter
  
  
          Public Sub New()
              catalogDataSet = New CatalogData()
              reportsTableAdapter = New ReportsTableAdapter()
              reportsTableAdapter.Fill(catalogDataSet.Reports)
              reportsTable = catalogDataSet.Tables("Reports")
          End Sub
  
  
          Public Overrides Function CanSetData(ByVal url As String) As Boolean
              ' Check if the URL is available in the report storage.
              Return reportsTable.Rows.Find(Integer.Parse(url)) IsNot Nothing
          End Function
  
  
          Public Overrides Function GetData(ByVal url As String) As Byte()
              ' Get the report data from the storage.
              Dim row As DataRow = reportsTable.Rows.Find(Integer.Parse(url))
              If row Is Nothing Then
                  Return Nothing
              End If
  
              Dim reportData() As Byte = DirectCast(row("LayoutData"), Byte())
              Return reportData
          End Function
  
  
          Public Overrides Function GetUrls() As Dictionary(Of String, String)
            ' Get URLs and display names for all reports available in the storage.
            Return reportsTable.AsEnumerable().ToDictionary(Function(dataRow) CInt((dataRow("ReportID"))).ToString(), Function(dataRow) CStr(dataRow("DisplayName")))
          End Function
  
  
          Public Overrides Function IsValidUrl(ByVal url As String) As Boolean
              ' Check if the specified URL is valid for the current report storage.
              ' In this example, a URL should be a string containing a numeric value that is used as a data row primary key.
              Dim n As Integer = Nothing
              Return Integer.TryParse(url, n)
          End Function
  
  
          Public Overrides Sub SetData(ByVal report As XtraReport, ByVal url As String)
              ' Write a report to the storage under the specified URL.
              Dim row As DataRow = reportsTable.Rows.Find(Integer.Parse(url))
  
              If row IsNot Nothing Then
                  Using ms As New MemoryStream()
                      report.SaveLayoutToXml(ms)
                      row("LayoutData") = ms.GetBuffer()
                  End Using
                  reportsTableAdapter.Update(catalogDataSet)
                  catalogDataSet.AcceptChanges()
              End If
          End Sub
  
  
          Public Overrides Function SetNewData(ByVal report As XtraReport, ByVal defaultUrl As String) As String
              ' Save a report to the storage under a new URL. 
              ' The defaultUrl parameter contains the report display name specified by a user.
              Dim row As DataRow = reportsTable.NewRow()
  
              row("DisplayName") = defaultUrl
              Using ms As New MemoryStream()
                  report.SaveLayoutToXml(ms)
                  row("LayoutData") = ms.GetBuffer()
              End Using
  
              reportsTable.Rows.Add(row)
              reportsTableAdapter.Update(catalogDataSet)
              catalogDataSet.AcceptChanges()
  
              ' Refill the dataset to obtain the actual value of the new row's autoincrement key field.
              reportsTableAdapter.Fill(catalogDataSet.Reports)
              Return catalogDataSet.Reports.FirstOrDefault(Function(x) x.DisplayName = defaultUrl).ReportID.ToString()
          End Function
      End Class
  End Namespace
  

• How to store reports in a file system:

  Note

  If you’d like to store reports in a file system, please refer to the following help topic for additional information/guidance: Create an ASP.NET Web Forms Application with a Report Designer.

  Show code

  C#

  using DevExpress.XtraReports.UI;
  using System;
  using System.Collections.Generic;
  using System.IO;
  using System.Linq;
  using System.ServiceModel;
  
  namespace DXWebApplication1.Services
  {
      public class ReportStorageWebExtension1 : 
          DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension
      {
          readonly string reportDirectory;
          const string FileExtension = ".repx";
          public ReportStorageWebExtension1(string reportDirectory) {
              if (!Directory.Exists(reportDirectory)) {
                  Directory.CreateDirectory(reportDirectory);
              }
              this.reportDirectory = reportDirectory;
          }
          public override bool CanSetData(string url) {
              return true;
          }
          public override bool IsValidUrl(string url) {
              return true;
          }
          public override byte[] GetData(string url) {
              // Gets the report layout data stored in a Report Storage by the specified URL. 
              try {
                  if (Directory.EnumerateFiles(reportDirectory).Select(Path.GetFileNameWithoutExtension).Contains(url))
                  {
                      return File.ReadAllBytes(Path.Combine(reportDirectory, url + FileExtension));
                  }
                  if (PredefinedReports.ReportsFactory.Reports.ContainsKey(url))
                  {
                      using (MemoryStream ms = new MemoryStream()) {
                          PredefinedReports.ReportsFactory.Reports[url]().SaveLayoutToXml(ms);
                          return ms.ToArray();
                      }
                  }
                  throw new FaultException(new FaultReason(string.Format("Could not find report '{0}'.", url)), new FaultCode("Server"), "GetData");
              } catch (Exception) {
                  throw new FaultException(new FaultReason(string.Format("Could not find report '{0}'.", url)), new FaultCode("Server"), "GetData");
              }
          }
          public override Dictionary<string, string> GetUrls() {
              // Returns a dictionary that contains report URLs and display names. 
              // This method is called when running the Report Designer, 
              // before the Open Report and Save Report dialogs and after a new report is saved to a storage.
  
              return Directory.GetFiles(reportDirectory, "*" + FileExtension)
                                       .Select(Path.GetFileNameWithoutExtension)
                                       .Concat(PredefinedReports.ReportsFactory.Reports.Select(x => x.Key))
                                       .ToDictionary<string, string>(x => x);
          }
          public override void SetData(XtraReport report, string url) {
              // Saves a report to the Report Storage with the specified URL. 
              report.SaveLayoutToXml(Path.Combine(reportDirectory, url + FileExtension));
          }
          public override string SetNewData(XtraReport report, string defaultUrl) {
              // Stores the report with a new URL. . 
              // Validate and correct the specified URL in the SetNewData method
              // and return the resulting URL that is used to save a report in the storage.
              SetData(report, defaultUrl);
              return defaultUrl;
          }
      }
  }
  

  VB.NET

  Imports System.IO
  Imports System.ServiceModel
  Imports DevExpress.XtraReports.UI
  
  Namespace Services
      Public Class ReportStorageWebExtension1
          Inherits DevExpress.XtraReports.Web.Extensions.ReportStorageWebExtension
  
          Private ReadOnly reportDirectory As String
          Private Const FileExtension As String = ".repx"
          Public Sub New(ByVal reportDirectory As String)
              If Not Directory.Exists(reportDirectory) Then
                  Directory.CreateDirectory(reportDirectory)
              End If
              Me.reportDirectory = reportDirectory
          End Sub
  
          Public Overrides Function CanSetData(ByVal url As String) As Boolean
              Return True
          End Function
  
          Public Overrides Function IsValidUrl(ByVal url As String) As Boolean
              Return True
          End Function
  
          Public Overrides Function GetData(ByVal url As String) As Byte()
              ' Gets the report layout data stored in a Report Storage by the specified URL. 
              Try
                  If Directory.EnumerateFiles(reportDirectory).Select(AddressOf Path.GetFileNameWithoutExtension).Contains(url) Then
                      Return File.ReadAllBytes(Path.Combine(reportDirectory, url & FileExtension))
                  End If
                  If PredefinedReports.ReportsFactory.Reports.ContainsKey(url) Then
                      Using ms As New MemoryStream()
                          PredefinedReports.ReportsFactory.Reports(url)().SaveLayoutToXml(ms)
                          Return ms.ToArray()
                      End Using
                  End If
                  Throw New FaultException(New FaultReason(String.Format("Could not find report '{0}'.", url)), New FaultCode("Server"), "GetData")
              Catch e1 As Exception
                  Throw New FaultException(New FaultReason(String.Format("Could not find report '{0}'.", url)), New FaultCode("Server"), "GetData")
              End Try
          End Function
  
          Public Overrides Function GetUrls() As Dictionary(Of String, String)
              '  Returns a dictionary that contains report URLs and display names.. 
              ' This method is called when running the Report Designer, 
              ' before the Open Report and Save Report dialogs and after a new report is saved to a storage.
  
              Return Directory.GetFiles(reportDirectory, "*" & FileExtension).
                  Select(AddressOf Path.GetFileNameWithoutExtension).
                  Concat(PredefinedReports.ReportsFactory.Reports.
                  Select(Function(x) x.Key)).ToDictionary(Function(x) x)
          End Function
  
          Public Overrides Sub SetData(ByVal report As XtraReport, ByVal url As String)
              ' Saves a report to the Report Storage with the specified URL. 
              report.SaveLayoutToXml(Path.Combine(reportDirectory, url & FileExtension))
          End Sub
  
          Public Overrides Function SetNewData(ByVal report As XtraReport, ByVal defaultUrl As String) As String
              ' Stores the report with a new URL. 
              ' Validate and correct the specified URL in the SetNewData method 
              ' and return the resulting URL that is used to save a report in the storage.
              SetData(report, defaultUrl)
              Return defaultUrl
          End Function
      End Class
  End Namespace 
  

Access the ASP.NET Session

If the ASP.NET End-User Report Designer works with a custom report storage, it uses a separate HTTP handler module for open and save operations. This means that the HttpContext.Session and HttpContext.User properties are not available from custom report storage code.

To access values stored in HttpContext/Session, use the technique described in the following help topic: Access HttpContext.Session in Services (ASP.NET Web Forms).