DataBind Charts to Avro Data

DataBinding facilitates two-way interaction with data through UI controls. Using the CData ADO.NET Provider for Avro streamlines the process of binding Avro data to Windows Forms and Web controls within Visual Studio. In this article, we will demonstrate using wizards to establish a binding between Avro 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 Avro, follow the steps outlined below using the Data Source Configuration Wizard. Within the wizard, you'll have the option to choose the specific Avro 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 Avro Data Source.

   Below is a typical connection string:

   URI=C:/folder/table.avro;InitiateOAuth=GETANDREFRESH;

   Connect to your local Avro file(s) by setting the URI connection property to the location of the Avro 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 SampleTable_1 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 Id and the y-axis to Column1.

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

Code Walk-through

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

1. Connect to Avro.
2. Create the AvroDataAdapter 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:

AvroConnection conn = new AvroConnection("URI=C:/folder/table.avro;InitiateOAuth=GETANDREFRESH;");
AvroCommand comm = new AvroCommand("SELECT Id, Column1 FROM SampleTable_1 WHERE Column2 = 'value_2'", conn);
AvroDataAdapter da = new AvroDataAdapter(comm);
DataSet dataset = new DataSet();
da.Fill(dataset);

chart1.DataSource = dataset; 
chart1.Series[0].XValueMember = "Id";
chart1.Series[0].YValueMembers = "Column1";
// Insert code for additional chart formatting here.
chart1.DataBind();