A storage of drivers used to manage writing/reading operations for data extracts.
Namespace: DevExpress.DashboardCommon
Assembly: DevExpress.Dashboard.v18.2.Core.dll
By default, the DashboardExtractDataSource stores data within a file. If necessary, you add a custom logic for writing/reading extract data by implementing the ICustomExtractDriver interface. After you have implemented a custom driver, you can use it in two ways.
This example demonstrates how to create a custom driver that will be used to encrypt/decrypt extract data by implementing the ICustomExtractDriver interface. The following methods are implemented for this interface.
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-implement-a-custom-logic-for-writing-data-to-reading-data-from-a-data-extract-t437252.
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using DevExpress.DashboardCommon;
namespace Dashboard_CustomExtractDriver {
public class ExtractEncryptionDriver : ICustomExtractDriver {
public IDriverReadSession CreateReadSession(string resourceName) {
return new EncryptionReadSession(FileExtractDriver.Instance.CreateReadSession(resourceName));
}
public IDriverWriteSession CreateWriteSession(string resourceName) {
return new EncryptionWriteSession(FileExtractDriver.Instance.CreateWriteSession(resourceName));
}
}
public class EncryptionWriteSession : IDriverWriteSession {
IDriverWriteSession writeSession;
public EncryptionWriteSession(IDriverWriteSession writeSession) {
this.writeSession = writeSession;
}
public void Dispose() {
writeSession.Dispose();
}
public void SetPage(Guid pageID, byte[] data) {
writeSession.SetPage(pageID, Encrypt(data));
}
byte[] Encrypt(byte[] page) {
byte[] entropy = { 1, 2, 3 };
byte[] encryptedPage = ProtectedData.Protect(page, entropy, DataProtectionScope.CurrentUser);
return encryptedPage;
}
}
public class EncryptionReadSession : IDriverReadSession {
IDriverReadSession readSession;
public EncryptionReadSession(IDriverReadSession readSession) {
this.readSession = readSession;
}
public void Dispose() {
readSession.Dispose();
}
byte[] Decrypt(byte[] page) {
byte[] entropy = { 1, 2, 3 };
byte[] decryptedPage = ProtectedData.Unprotect(page, entropy, DataProtectionScope.CurrentUser);
return decryptedPage;
}
public byte[] GetPage(Guid pageID) {
return Decrypt(readSession.GetPage(pageID));
}
public IEnumerable<Guid> GetPageIDs() {
return readSession.GetPageIDs();
}
}
}
using DevExpress.DashboardCommon;
using DevExpress.DataAccess.ConnectionParameters;
using DevExpress.DataAccess.Sql;
using DevExpress.XtraEditors;
namespace Dashboard_CustomExtractDriver {
public partial class Form1 : XtraForm {
public Form1() {
InitializeComponent();
ExtractDriverStorage.DefaultDriver = new ExtractEncryptionDriver();
DashboardSqlDataSource sqlDataSource = new DashboardSqlDataSource();
sqlDataSource.DataProcessingMode = DataProcessingMode.Client;
Access2007ConnectionParameters connectionParams = new Access2007ConnectionParameters(@"..\..\Data\Northwind.accdb", "");
sqlDataSource.ConnectionParameters = connectionParams;
SelectQuery selectQuery = SelectQueryFluentBuilder
.AddTable("Invoices")
.SelectColumns("ExtendedPrice", "Quantity", "OrderDate", "ProductName")
.Build("Query 1");
sqlDataSource.Queries.Add(selectQuery);
sqlDataSource.Fill();
DashboardExtractDataSource extractDataSource = new DashboardExtractDataSource();
extractDataSource.ExtractSourceOptions.DataSource = sqlDataSource;
extractDataSource.ExtractSourceOptions.DataMember = "Query 1";
extractDataSource.FileName = @".\InvoicesExtract.dat";
extractDataSource.UpdateExtractFile();
Dashboard dashboard = new Dashboard();
dashboard.DataSources.Add(extractDataSource);
PivotDashboardItem pivot = new PivotDashboardItem();
pivot.DataSource = extractDataSource;
pivot.Values.AddRange(new Measure("ExtendedPrice"), new Measure("Quantity"));
pivot.Columns.Add(new Dimension("OrderDate", DateTimeGroupInterval.Year));
pivot.Rows.Add(new Dimension("ProductName"));
dashboard.Items.Add(pivot);
dashboardViewer1.Dashboard = dashboard;
}
}
}
Imports System
Imports System.Collections.Generic
Imports System.Security.Cryptography
Imports DevExpress.DashboardCommon
Namespace Dashboard_CustomExtractDriver
Public Class ExtractEncryptionDriver
Implements ICustomExtractDriver
Public Function CreateReadSession(ByVal resourceName As String) As _
IDriverReadSession Implements ICustomExtractDriver.CreateReadSession
Return New EncryptionReadSession(FileExtractDriver.Instance.CreateReadSession(resourceName))
End Function
Public Function CreateWriteSession(ByVal resourceName As String) As _
IDriverWriteSession Implements ICustomExtractDriver.CreateWriteSession
Return New EncryptionWriteSession(FileExtractDriver.Instance.CreateWriteSession(resourceName))
End Function
End Class
Public Class EncryptionWriteSession
Implements IDriverWriteSession
Private writeSession As IDriverWriteSession
Public Sub New(ByVal writeSession As IDriverWriteSession)
Me.writeSession = writeSession
End Sub
Public Sub Dispose() Implements System.IDisposable.Dispose
writeSession.Dispose()
End Sub
Public Sub SetPage(ByVal pageID As Guid, ByVal data() As Byte) Implements IDriverWriteSession.SetPage
writeSession.SetPage(pageID, Encrypt(data))
End Sub
Private Function Encrypt(ByVal page() As Byte) As Byte()
Dim entropy() As Byte = {1, 2, 3}
Dim encryptedPage() As Byte = ProtectedData.Protect(page, entropy, DataProtectionScope.CurrentUser)
Return encryptedPage
End Function
End Class
Public Class EncryptionReadSession
Implements IDriverReadSession
Private readSession As IDriverReadSession
Public Sub New(ByVal readSession As IDriverReadSession)
Me.readSession = readSession
End Sub
Public Sub Dispose() Implements System.IDisposable.Dispose
readSession.Dispose()
End Sub
Private Function Decrypt(ByVal page() As Byte) As Byte()
Dim entropy() As Byte = {1, 2, 3}
Dim decryptedPage() As Byte = ProtectedData.Unprotect(page, entropy, DataProtectionScope.CurrentUser)
Return decryptedPage
End Function
Public Function GetPage(ByVal pageID As Guid) As Byte() Implements IDriverReadSession.GetPage
Return Decrypt(readSession.GetPage(pageID))
End Function
Public Function GetPageIDs() As IEnumerable(Of Guid) Implements IDriverReadSession.GetPageIDs
Return readSession.GetPageIDs()
End Function
End Class
End Namespace
Imports DevExpress.DashboardCommon
Imports DevExpress.DataAccess.ConnectionParameters
Imports DevExpress.DataAccess.Sql
Imports DevExpress.XtraEditors
Namespace Dashboard_CustomExtractDriver
Partial Public Class Form1
Inherits XtraForm
Public Sub New()
InitializeComponent()
ExtractDriverStorage.DefaultDriver = New ExtractEncryptionDriver()
Dim sqlDataSource As New DashboardSqlDataSource()
sqlDataSource.DataProcessingMode = DataProcessingMode.Client
Dim connectionParams As New Access2007ConnectionParameters("..\..\Data\Northwind.accdb", "")
sqlDataSource.ConnectionParameters = connectionParams
Dim selectQuery As SelectQuery = SelectQueryFluentBuilder.AddTable("Invoices").
SelectColumns("ExtendedPrice", "Quantity", "OrderDate", "ProductName").Build("Query 1")
sqlDataSource.Queries.Add(selectQuery)
sqlDataSource.Fill()
Dim extractDataSource As New DashboardExtractDataSource()
extractDataSource.ExtractSourceOptions.DataSource = sqlDataSource
extractDataSource.ExtractSourceOptions.DataMember = "Query 1"
extractDataSource.FileName = ".\InvoicesExtract.dat"
extractDataSource.UpdateExtractFile()
Dim dashboard As New Dashboard()
dashboard.DataSources.Add(extractDataSource)
Dim pivot As New PivotDashboardItem()
pivot.DataSource = extractDataSource
pivot.Values.AddRange(New Measure("ExtendedPrice"), New Measure("Quantity"))
pivot.Columns.Add(New Dimension("OrderDate", DateTimeGroupInterval.Year))
pivot.Rows.Add(New Dimension("ProductName"))
dashboard.Items.Add(pivot)
dashboardViewer1.Dashboard = dashboard
End Sub
End Class
End Namespace