# Data Binding ## Content We’ll begin by creating a new Windows Forms project in Visual Studio. 1. In Visual Studio, choose **File | New Project.** 2. Select the **Windows Forms Application** template and click **OK**. Next, add an Entity Data Model based on the Northwind database. This model will provide the data for the entire application: 1. In the **Solution Explorer**, right-click the project name and select **Add | New Item**. 2. In the **Data** category, select the "ADO.NET Data Model" item and then click **Add**. 3. Use the **Entity Data Model Wizard** to select the database you want to use. In this example, you will use "NORTHWND.MDF", which should be installed in the **ComponentOne Samples\\Common** folder. 4. In the Solution Explorer, expand the mode next to _model1.edmx_. 5. Delete the _Model1.Context.tt_ file and the _Model1.tt_ file. 6. Right click the model diagram and select **Add Code Generation Item** from the context menu. Select ‘**ComponentOne EF 6.x DbContext Generator’ from the Add Code Generation Item Dialog box**. > type=note > **Note**: When you install **DataSource for Entity Framework**, **ComponentOne EF6.x DBContext Code Generation Templates** will be added to each version of Visual Studio that [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) supports. These templates ensure that the DBContext models that you create, provide entities that support **INotifyPropertyChanged**. Now build the project so the new Entity Data Model classes are generated and become available throughout the project. Next, add a [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) component to the application and connect it to the Entity Data Model: 1. Drag a [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) component from the Toolbox onto the form. This is a non-visual component, so it will appear on the tray below the form area rather than on the form itself. 2. Select the new component and choose **View | Properties Window**. 3. In the Properties window, set the **ContextType** property to the type of object context you want to use. In this case, there should be only one option in the drop-down list, something similar to "AppName.NORTHWINDEntities". At this point, the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) has created an application-wide object (an **EntityDataCache**) that represents the Northwind database and has application scope. Additional [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) objects on other forms will share that same object. As long as they are part of the same application, all [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) objects share the same **ObjectContext**. This unified object context is one of the main advantages [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) provides. Without it, you would have to create multiple object contexts throughout the application, and each would have to be synchronized with the others and with the underlying database separately. This would be a non-trivial task, and any errors could compromise the integrity of the data. The unified object context handles that for you transparently. It efficiently caches data and makes it available to all views in a safe, consistent way. Now that our [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) has an **ObjectContext** to work with, we will go on to specify the entity sets it will expose to the application through its **ViewSources** collection. Note that if you are familiar with ADO.NET, you can think of the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) as a **DataSet** and the **ViewSources** collection as **DataView** objects. In the properties of the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html), locate the **ViewSourcesCollection** property and open its editor dialog. Click **Add** and then select _Products_ from the **EntitySetName** drop-down list. ![](https://cdn.mescius.io/document-site-files/images/94bcede7-c342-4bf9-97a8-95fb8706d41c/simple_binding_files/image001.jpg) For this simple example, _Products_ is all that is really necessary, but we could continue to create **ViewSources** within this [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) in exactly the same way. We might, for example, create a **ViewSource** based on the _Categories_ entity set allowing us to have a form that would be used to show the master-detail relationship between _Categories_ and their _Products_. Conversely, there is no need to define all of the **ViewSources** that you might need in one single [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html). You could have a separate [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) for each **ViewSource** that you need. All you need to do is ensure that the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) components that you use utilize the same **ContextType**. In reality we’ll only want to bring a small subsection of the data contained within our database back to the client at any one time. This avoids overloading the client and network and also ensures that we are only presenting data that is relevant to the task our end user is engaged in. The traditional approach to this has been to create code (typically SQL queries) that we would run against the database to achieve our desired results. With [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html), we can make use of the designer surface to achieve our goal without the need to write code by specifying server-side filters as property settings. From the **ViewSourceCollection** editor, open the **FilterDescriptor** collection editor, add a filter descriptor and type the property name and a value for it for server-side filtering. If you need to filter more than one property, you can add additional filter descriptors. ![](https://cdn.mescius.io/document-site-files/images/94bcede7-c342-4bf9-97a8-95fb8706d41c/simple_binding_files/image002.png) Using exactly the same methodology, you can add **SortDescriptors** provide sorting on the data you retrieve. With our [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) configured, add a grid control to the form. This can be **DataGridView**, a **C1FlexGrid** or indeed any grid that you are familiar with. Set the grid’s DataSource property to the name of the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html) (if you haven’t specifically named the **C1DataSource,** then this will be _c1DataSource1_) and its **DataMember** property to _Products_. The **DataMember** property will, in fact, display a drop-down list of all the **ViewSources** (or Entity Sets) that we defined for the [C1DataSource](/componentone/api/win/online-datasource/dotnet-framework-api/C1.Win.Data.Entity.4.8/C1.Win.Data.Entities.C1DataSource.html). ![](https://cdn.mescius.io/document-site-files/images/94bcede7-c342-4bf9-97a8-95fb8706d41c/simple_binding_files/image003.jpg)![](https://cdn.mescius.io/document-site-files/images/94bcede7-c342-4bf9-97a8-95fb8706d41c/simple_binding_files/image004.jpg) At this point, the grid will automatically generate columns for all the fields in the _Product_ type, and most grids will allow you to further customize these columns and their layout via their built-in designers. Once you are happy with the grid's layout, save, build, and run the application. Notice that the data loads automatically and that you can sort, add and remove items as you’d expect to be able to do. All this has been achieved by adding just two items to your form (a **C1DatSource** and a data grid) and setting a few properties. You did not have to write a single line of code! You could continue to add more controls to this form and bind them to specific items in the _Products_ collection. To illustrate this point, add a **TextBox** control to the form. From the Properties window, expand the **DataBindings** section and bind its **Text** property to the _ProductName_, as illustrated. ![](https://cdn.mescius.io/document-site-files/images/94bcede7-c342-4bf9-97a8-95fb8706d41c/simple_binding_files/image005.jpg) Save, build and run the application again, and this time notice how the name of the product currently selected in the grid appears in the **TextBox** that you have just added to the form. If you then edit the product name in either control, the change will be immediately reflected in the other.