Entity Framework Data Source

• Dec 04, 2020
• 4 minutes to read

This tutorial shows how to add the DashboardEFDataSource to a data source storage and make it available to users. The tutorial uses the MDF database.

1. In your application, add the NWind.mdf database to the App_Data folder from the C:\Users\Public\Documents\DevExpress Demos 20.2\Components\Data directory.

2. In Web.config, specify a connection string to the database.

   <configuration>
       <connectionStrings>
           <add name="NWindConnectionString" connectionString="data source=(localdb)\mssqllocaldb;attachdbfilename=|DataDirectory|\NWind.mdf;integrated security=True;connect timeout=120" providerName="System.Data.SqlClient" />        
       </connectionStrings>
   </configuration>
   

3. Right-click the project and select Add | ADO.NET Entity Data Model. Specify OrdersContext as the model name and select the Code First from database model type in the invoked wizard.
4. Select the added NWindConnectionString as a data connection for the created model.

5. On the next page, specify which tables and view to include in your model. In this tutorial, the data model is based on the OrderDetail table. The code below shows the generated data model.

   C#:

   OrdersContext.cs

   namespace WebFormsDashboardDataSources {
       using System.Data.Entity;
   
       public partial class OrdersContext: DbContext {
           public OrdersContext()
               : base("name=OrdersContext") {
           }
   
           public virtual DbSet<OrderDetail> OrderDetails { get; set; }
   
           protected override void OnModelCreating(DbModelBuilder modelBuilder) {
               modelBuilder.Entity<OrderDetail>()
                   .Property(e => e.UnitPrice)
                   .HasPrecision(10, 4);
           }
       }
   }
   

   OrderDetail.cs

   namespace WebFormsDashboardDataSources {
       using System.ComponentModel.DataAnnotations;
       using System.ComponentModel.DataAnnotations.Schema;
   
       public partial class OrderDetail
       {
           [Key]
           [Column(Order = 0)]
           [DatabaseGenerated(DatabaseGeneratedOption.None)]
           public int OrderID { get; set; }
   
           [Column(Order = 1)]
           [DatabaseGenerated(DatabaseGeneratedOption.None)]
           public short Quantity { get; set; }
   
           [Column(Order = 2, TypeName = "smallmoney")]
           public decimal UnitPrice { get; set; }
   
           [Column(Order = 3)]
           public float Discount { get; set; }
   
           [Column(Order = 4)]
           [StringLength(40)]
           public string ProductName { get; set; }
   
           [StringLength(217)]
           public string Supplier { get; set; }
       }
   }
   

   Visual Basic:

   OrdersContext.vb

   Imports System.Data.Entity
   Namespace WebFormsDashboardDataSources
   
       Partial Public Class OrdersContext
           Inherits DbContext
           Public Sub New()
               MyBase.New("name=OrdersContext")
           End Sub
   
           Private privateOrderDetails As DbSet(Of OrderDetail)
           Public Overridable Property OrderDetails() As DbSet(Of OrderDetail)
               Get
                   Return privateOrderDetails
               End Get
               Set(ByVal value As DbSet(Of OrderDetail))
                   privateOrderDetails = value
               End Set
           End Property
   
           Protected Overrides Sub OnModelCreating(ByVal modelBuilder As DbModelBuilder)
               modelBuilder.Entity(Of OrderDetail)().Property(Function(e) e.UnitPrice).HasPrecision(10, 4)
           End Sub
       End Class
   End Namespace
   

   OrderDetail.vb

   Imports System.ComponentModel.DataAnnotations
   Imports System.ComponentModel.DataAnnotations.Schema
   
   Namespace WebFormsDashboardDataSources
   
       Partial Public Class OrderDetail
           Private privateOrderID As Integer
           <Key, Column(Order := 0), DatabaseGenerated(DatabaseGeneratedOption.None)> _
           Public Property OrderID() As Integer
               Get
                   Return privateOrderID
               End Get
               Set(ByVal value As Integer)
                   privateOrderID = value
               End Set
           End Property
   
           Private privateQuantity As Short
           <Column(Order := 1), DatabaseGenerated(DatabaseGeneratedOption.None)> _
           Public Property Quantity() As Short
               Get
                   Return privateQuantity
               End Get
               Set(ByVal value As Short)
                   privateQuantity = value
               End Set
           End Property
   
           Private privateUnitPrice As Decimal
           <Column(Order := 2, TypeName := "smallmoney")> _
           Public Property UnitPrice() As Decimal
               Get
                   Return privateUnitPrice
               End Get
               Set(ByVal value As Decimal)
                   privateUnitPrice = value
               End Set
           End Property
   
           Private privateDiscount As Single
           <Column(Order := 3)> _
           Public Property Discount() As Single
               Get
                   Return privateDiscount
               End Get
               Set(ByVal value As Single)
                   privateDiscount = value
               End Set
           End Property
   
           Private privateProductName As String
           <Column(Order := 4), StringLength(40)> _
           Public Property ProductName() As String
               Get
                   Return privateProductName
               End Get
               Set(ByVal value As String)
                   privateProductName = value
               End Set
           End Property
   
           Private privateSupplier As String
           <StringLength(217)> _
           Public Property Supplier() As String
               Get
                   Return privateSupplier
               End Get
               Set(ByVal value As String)
                   privateSupplier = value
               End Set
           End Property
       End Class
   End Namespace
   

6. In the Default.aspx.cs (or .vb) file, create a public method that returns the configured dashboard’s data source storage (DataSourceInMemoryStorage) and define the EF data source.

   C#

   using System;
   using DevExpress.DashboardCommon;
   using DevExpress.DashboardWeb;
   using DevExpress.DataAccess.EntityFramework;
   
   public DataSourceInMemoryStorage CreateDataSourceStorage() {
       DataSourceInMemoryStorage dataSourceStorage = new DataSourceInMemoryStorage();
   
       DashboardEFDataSource efDataSource = new DashboardEFDataSource("EF Core Data Source");
       efDataSource.ConnectionParameters = new EFConnectionParameters(typeof(OrdersContext));
       dataSourceStorage.RegisterDataSource("efDataSource", efDataSource.SaveToXml());
   
       return dataSourceStorage;
   }
   

   VB.NET

   Imports System
   Imports DevExpress.DashboardCommon
   Imports DevExpress.DashboardWeb
   Imports DevExpress.DataAccess.EntityFramework
   
   Public Function CreateDataSourceStorage() As DataSourceInMemoryStorage
       Dim dataSourceStorage As New DataSourceInMemoryStorage()
   
       Dim efDataSource As New DashboardEFDataSource("EF Core Data Source")
       efDataSource.ConnectionParameters = New EFConnectionParameters(GetType(OrdersContext))
       dataSourceStorage.RegisterDataSource("efDataSource", efDataSource.SaveToXml())
   
       Return dataSourceStorage
   End Function
   

7. Call the ASPxDashboard.SetDataSourceStorage method to configure the data source storage. Use the created CreateDataSourceStorage method as the SetDataSourceStorage parameter.

   C#

   using DevExpress.DashboardWeb;
   
   protected void Page_Load(object sender, EventArgs e) {
       // ...  
   
       // Configures the data source storage.
       ASPxDashboard1.SetDataSourceStorage(CreateDataSourceStorage());
   }
   

   VB.NET

   Imports DevExpress.DashboardWeb
   
   Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
       ' ...          
   
       '  Configures the data source storage.
       ASPxDashboard1.SetDataSourceStorage(CreateDataSourceStorage())
   End Sub
   

The EF Data Source is now available in the Web Dashboard:

Users can now bind dashboard items to data in the Web Dashboard’s UI.

Example

The example shows how to make a set of data sources available for users in the Web Dashboard application.

View Example: How to Register Data Sources for ASP.NET Web Forms Dashboard Control