How to Access Cvent Data Using Entity Framework

Microsoft Entity Framework serves as an object-relational mapping framework for working with data represented as objects. Although Visual Studio offers the ADO.NET Entity Data Model wizard to automatically generate the Entity Model, this model-first approach may present challenges when your data source undergoes changes or when you require greater control over entity operations. In this article, we will delve into the code-first approach for accessing Cvent data through the CData ADO.NET Provider, providing you with more flexibility and control.

1. Open Visual Studio and create a new Windows Form Application. This article uses a C# project with .NET 4.5.
2. Run the command 'Install-Package EntityFramework' in the Package Manger Console in Visual Studio to install the latest release of Entity Framework.

3. Modify the App.config file in the project to add a reference to the Cvent Entity Framework 6 assembly and the connection string.

   Before you can authenticate to Cvent, you must create a workspace and an OAuth application.

   Creating a Workspace

   To create a workspace:

   1. Sign into Cvent and navigate to App Switcher (the blue button in the upper right corner of the page) >> Admin.
   2. In the Admin menu, navigate to Integrations >> REST API.
   3. A new tab launches for Developer Management. Click on Manage API Access in the new tab.
   4. Create a Workspace and name it. Select the scopes you would like your developers to have access to. Scopes control what data domains the developer can access.
      • Choose All to allow developers to choose any scope, and any future scopes added to the REST API.
      • Choose Custom to limit the scopes developers can choose for their OAuth apps to selected scopes. To access all tables exposed by the driver, you need to set the following scopes:

        event/attendees:read	event/attendees:write	event/contacts:read
        event/contacts:write	event/custom-fields:read	event/custom-fields:write
        event/events:read	event/events:write	event/sessions:delete
        event/sessions:read	event/sessions:write	event/speakers:delete
        event/speakers:read	event/speakers:write	budget/budget-items:read
        budget/budget-items:write	exhibitor/exhibitors:read	exhibitor/exhibitors:write
        survey/surveys:read	survey/surveys:write

   Creating an OAuth Application

   After you have set up a Workspace and invited them, developers can sign up and create a custom OAuth app. See the Creating a Custom OAuth Application section in the Help documentation for more information.

   Connecting to Cvent

   After creating an OAuth application, set the following connection properties to connect to Cvent:

   • InitiateOAuth: GETANDREFRESH. Used to automatically get and refresh the OAuthAccessToken.
   • OAuthClientId: The Client ID associated with the OAuth application. You can find this on the Applications page in the Cvent Developer Portal.
   • OAuthClientSecret: The Client secret associated with the OAuth application. You can find this on the Applications page in the Cvent Developer Portal.

   <configuration>
    ... 
    <connectionStrings>
    <add name="CventContext" connectionString="Offline=False;OAuthClientId=MyOAuthClientId;OAuthClientSecret=MyOAuthClientSecret;InitiateOAuth=GETANDREFRESH;" providerName="System.Data.CData.Cvent" />
    </connectionStrings>
    <entityFramework>
    <providers>
    ... 
    <provider invariantName="System.Data.CData.Cvent" type="System.Data.CData.Cvent.CventProviderServices, System.Data.CData.Cvent.Entities.EF6" />
    </providers>
    <entityFramework>
   </configuration>
   </code> 
   

4. Add a reference to System.Data.CData.Cvent.Entities.EF6.dll, located in the lib -> 4.0 subfolder in the installation directory.
5. Build the project at this point to ensure everything is working correctly. Once that's done, you can start coding using Entity Framework.
6. Add a new .cs file to the project and add a class to it. This will be your database context, and it will extend the DbContext class. In the example, this class is named CventContext. The following code example overrides the OnModelCreating method to make the following changes:
   • Remove PluralizingTableNameConvention from the ModelBuilder Conventions.
   • Remove requests to the MigrationHistory table.

   using System.Data.Entity;
   using System.Data.Entity.Infrastructure;
   using System.Data.Entity.ModelConfiguration.Conventions;
   
   class CventContext : DbContext {
    public CventContext() { }
   
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
    // To remove the requests to the Migration History table
    Database.SetInitializer<CventContext>(null); 
    // To remove the plural names 
    modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    } 
   }
   

7. Create another .cs file and name it after the Cvent entity you are retrieving, for example, Events. In this file, define both the Entity and the Entity Configuration, which will resemble the example below:

   using System.Data.Entity.ModelConfiguration;
   using System.ComponentModel.DataAnnotations.Schema;
   
   [System.ComponentModel.DataAnnotations.Schema.Table("Events")]
   public class Events {
    [System.ComponentModel.DataAnnotations.Key] 
    public System.String Id { get; set; }
    public System.String Title { get; set; }
   }
    
   

8. Now that you have created an entity, add the entity to your context class:

   public DbSet<Events> Events { set; get; }
   

9. With the context and entity finished, you are now ready to query the data in a separate class. For example:

   CventContext context = new CventContext();
   context.Configuration.UseDatabaseNullSemantics = true;
   var query = from line in context.Events select line;