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DataBind JSON Services to the DevExpress Data Grid

Use the CData ADO.NET Provider for JSON with the DevExpress Windows Forms and Web controls to provide JSON services to a chart.

The CData ADO.NET Provider for JSON implements standard ADO.NET data access components that can be used with third-party controls. The standard ADO.NET process for databinding can be followed to enable bidirectional access to live data from UI controls. In this article we show how to use the CData components to databind to the DevExpress Windows Forms and Web controls; you will databind to a chart that displays current data.

See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models JSON APIs as bidirectional database tables and JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

After setting the URI and providing any authentication values, set DataModel to more closely match the data representation to the structure of your data.

The DataModel property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

  • Document (default): Model a top-level, document view of your JSON data. The data provider returns nested elements as aggregates of data.
  • FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
  • Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

See the Modeling JSON Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

Windows Forms Controls

The code below shows how to populate a DevExpress chart with JSON services. The JSONDataAdapter binds to the Series property of the chart control. The Diagram property of the control defines the x- and y-axes as the column names.

using (JSONConnection connection = new JSONConnection( "URI=C:\people.json;DataModel=Relational;")) { JSONDataAdapter dataAdapter = new JSONDataAdapter( "SELECT [people].[personal.age] AS age, [people].[personal.gender] AS gender, [people].[personal.name.first] AS first_name, [people].[personal.name.last] AS last_name, [vehicles].[model], FROM [people] JOIN [vehicles] ON [people].[_id] = [vehicles].[people_id]", connection); DataTable table = new DataTable(); dataAdapter.Fill(table); DevExpress.XtraCharts.Series series = new DevExpress.XtraCharts.Series(); chartControl1.Series.Add(series); series.DataSource = table; series.ValueDataMembers.AddRange(new string[] { "[ personal.name.last ]" }); series.ArgumentScaleType = DevExpress.XtraCharts.ScaleType.Qualitative; series.ArgumentDataMember = "[ personal.name.first ]"; series.ValueScaleType = DevExpress.XtraCharts.ScaleType.Numerical; chartControl1.Legend.Visibility = DevExpress.Utils.DefaultBoolean.False; ((DevExpress.XtraCharts.SideBySideBarSeriesView)series.View).ColorEach = true; }

Web Controls

The code below shows how to populate a DevExpress Web control with JSON services. The JSONDataAdapter binds to the Series property of the chart; the Diagram property defines the x- and y-axes as the column names.

using DevExpress.XtraCharts; using (JSONConnection connection = new JSONConnection( "URI=C:\people.json;DataModel=Relational;")) { JSONDataAdapter JSONDataAdapter1 = new JSONDataAdapter("SELECT [people].[personal.age] AS age, [people].[personal.gender] AS gender, [people].[personal.name.first] AS first_name, [people].[personal.name.last] AS last_name, [vehicles].[model], FROM [people] JOIN [vehicles] ON [people].[_id] = [vehicles].[people_id]", connection); DataTable table = new DataTable(); JSONDataAdapter1.Fill(table); DevExpress.XtraCharts.Series series = new Series("Series1", ViewType.Bar); WebChartControl1.Series.Add(series); series.DataSource = table; series.ValueDataMembers.AddRange(new string[] { "[ personal.name.last ]" }); series.ArgumentScaleType = ScaleType.Qualitative; series.ArgumentDataMember = "[ personal.name.first ]"; series.ValueScaleType = ScaleType.Numerical; ((DevExpress.XtraCharts.SideBySideBarSeriesView)series.View).ColorEach = true; }
 
 
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