DataBind Charts to eBay Data

DataBinding facilitates two-way interaction with data through UI controls. Using the CData ADO.NET Provider for eBay streamlines the process of binding eBay data to Windows Forms and Web controls within Visual Studio. In this article, we will demonstrate using wizards to establish a binding between eBay data 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.

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 eBay, follow the steps outlined below using the Data Source Configuration Wizard. Within the wizard, you'll have the option to choose the specific eBay 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 eBay Data Source.

   Below is a typical connection string:

   AppId=MyAppId;CertId=MyCertId;DevId=MyDevId;SiteId=MySiteId;RuName=MyRuName;CallbackURL=http://localhost:33333;InitiateOAuth=GETANDREFRESH;

   If you will be accessing your own account, you can generate an OAuthAccessToken from your developer account dashboard. You can also allow other users to securely access their own accounts.

   Both of these methods require you to create an application key set to obtain values for the following connection properties: AppId, CertId, DevId, and SiteId.

   The user consent flow additionally requires the RuName and CallbackURL.

   See the "Getting Started" chapter in the help documentation for a guide to using OAuth.

   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 ItemListing 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 Title and the y-axis to HitCount.

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 eBay data. Run the chart to display the current data. 👁 The chart, filled with data at run time.

Code Walk-through

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

1. Connect to eBay.
2. Create the EbayDataAdapter 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:

EbayConnection conn = new EbayConnection("AppId=MyAppId;CertId=MyCertId;DevId=MyDevId;SiteId=MySiteId;RuName=MyRuName;CallbackURL=http://localhost:33333;InitiateOAuth=GETANDREFRESH;");
EbayCommand comm = new EbayCommand("SELECT Title, HitCount FROM ItemListing", conn);
EbayDataAdapter da = new EbayDataAdapter(comm);
DataSet dataset = new DataSet();
da.Fill(dataset);

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