DataBind Charts to OData Services

DataBinding facilitates two-way interaction with data through UI controls. Using the CData ADO.NET Provider for OData streamlines the process of binding OData services to Windows Forms and Web controls within Visual Studio. In this article, we will demonstrate using wizards to establish a binding between OData services and a chart that dynamically updates. Additionally, the code walk-through section will guide you through the creation of a chart using just 10 lines of code.

Getting Started

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Binding Data to a Chart

DataBinding to a Chart consists of three steps: Instantiate the control, configure the data source, and databind.

Configure the Connection and Select Database Objects

To create a chart control and establish a connection to OData, follow the steps outlined below using the Data Source Configuration Wizard. Within the wizard, you'll have the option to choose the specific OData entities you wish to bind to.

1. In a Windows Forms project, drag and drop a Chart control from the toolbox to the form. In the Data section of the Chart properties, select DataSource and then select Add Project Data Source from the menu. 👁 Add a data source to be bound to the chart.
   
2. In the Data Source Configuration Wizard that appears, select Database -> Dataset.
3. In the Choose Your Data Connection step, click New Connection.

4. In the Add Connection dialog, click Change to select the CData OData Data Source.

   Below is a typical connection string:

   URL=http://services.odata.org/V4/Northwind/Northwind.svc;UseIdUrl=True;OData Version=4.0;Data Format=ATOM;

   The User and Password properties, under the Authentication section, must be set to valid OData user credentials. In addition, specify a URL to a valid OData server organization root or OData services file.

   When you configure the connection, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

   👁 Connection properties for the selected data source in the Add Connection dialog. (Salesforce is shown.)
   
5. Choose the database objects you want to work with. This example uses the Orders table. 👁 Select database objects. (Salesforce is shown.)
   

DataBind

After adding the data source and selecting database objects, you can bind the objects to the chart. This example assigns the x-axis to OrderName and the y-axis to Freight.

1. In the Chart properties, click the button in the Series property to open the Series Collection Editor.
2. In the Series properties, select the columns you want for the x- and y-axes: Select columns from the menu in the XValueMember and YValueMember properties.

The chart is now databound to the OData services. Run the chart to display the current data. 👁 The chart, filled with data at run time.

Code Walk-through

DataBinding to OData services requires only a few lines of code and can be completed in three easy steps.

1. Connect to OData.
2. Create the ODataDataAdapter to execute the query and create a DataSet to be filled with its results.
3. DataBind the result set to the chart.

Below is the complete code:

ODataConnection conn = new ODataConnection("URL=http://services.odata.org/V4/Northwind/Northwind.svc;UseIdUrl=True;OData Version=4.0;Data Format=ATOM;");
ODataCommand comm = new ODataCommand("SELECT Orders.Freight, Customers.ContactName FROM Customers INNER JOIN Orders ON Customers.CustomerId=Orders.CustomerId", conn);
ODataDataAdapter da = new ODataDataAdapter(comm);
DataSet dataset = new DataSet();
da.Fill(dataset);

chart1.DataSource = dataset; 
chart1.Series[0].XValueMember = "OrderName";
chart1.Series[0].YValueMembers = "Freight";
// Insert code for additional chart formatting here.
chart1.DataBind();