DashboardJsonDataSource Class
A data source that retrieves data stored in JSON format.
Namespace: DevExpress.DashboardCommon
Assembly: DevExpress.Dashboard.v24.2.Core.dll
Declaration
public class DashboardJsonDataSource :
JsonDataSource,
IDashboardDataSource,
IDashboardComponent,
IComponent,
IDisposable,
ISupportInitialize,
ISupportPrefix,
IDashboardDataSourceInternal,
IExternalSchemaConsumer,
IFederationDataProviderRemarks
The DashboardJsonDataSource allows you to extract JSON data from a Web-service endpoint URI, text file, or a string in JSON format.
Important
The DashboardJsonDataSource object requires the System.Text.Json library. .NET projects do not require manual installation of the System.Text.Json package, as it is already included in the .NET environment. Set the DevExpress.DataAccess.Native.Json.JsonLoaderHelper.ProcessingLibrary property to NewtonsoftJson to use the Newtonsoft.Json library instead. Then, install the Newtonsoft.Json NuGet package.
You can read files from any directory by default. To protect your application, use the AccessSettings class to explicitly specify where data sources can be read from. To accomplish this, configure rules in the DataResources property to restrict file system access to specified folders. You can call the SetRules(IAccessRule[]) method when your application starts to specify rules before a dashboard control sets its rules. The SetRules(IAccessRule[]) method can be called only once at application startup. Otherwise, the method will raise an exception. Alternatively, you can use the TrySetRules(IAccessRule[]) method, which does not raise an exception.
Design Time
Follow the step-by-step instructions in the following topic: How to create JSON Data Source at design time.
Runtime
- Create the
DashboardJsonDataSourceinstance with a simple constructor. - Use the JsonSource property to specify the JSON data location.
- Use the RootElement property to specify a root JSON node.
- Add the created data source to the dashboard’s Dashboard.DataSources collection.
- Assign the created data source to the dashboard item’s DataDashboardItem.DataSource property.
The code sample below illustrates how to retrieve JSON data from different sources:
using DevExpress.DashboardCommon;
using DevExpress.DataAccess.Json;
// ...
public void InitializeDashboard() {
Dashboard dashboard = new Dashboard();
DashboardJsonDataSource jsonDataSourceFromWeb = CreateJsonDataSourceFromWeb();
DashboardJsonDataSource jsonDataSourceFromFile = CreateJsonDataSourceFromFile();
DashboardJsonDataSource jsonDataSourceFromString = CreateJsonDataSourceFromString();
dashboard.DataSources.Add(jsonDataSourceFromWeb);
dashboard.DataSources.Add(jsonDataSourceFromFile);
dashboard.DataSources.Add(jsonDataSourceFromString);
}
public static DashboardJsonDataSource CreateJsonDataSourceFromWeb()
{
var jsonDataSource = new DashboardJsonDataSource();
jsonDataSource.JsonSource = new UriJsonSource(new Uri("https://raw.githubusercontent.com/DevExpress-Examples/DataSources/master/JSON/customers.json"));
jsonDataSource.RootElement = "Customers";
return jsonDataSource;
}
public static DashboardJsonDataSource CreateJsonDataSourceFromFile()
{
var jsonDataSource = new DashboardJsonDataSource();
Uri fileUri = new Uri("customers.json", UriKind.RelativeOrAbsolute);
jsonDataSource.JsonSource = new UriJsonSource(fileUri);
jsonDataSource.RootElement = "Customers";
return jsonDataSource;
}
public static DashboardJsonDataSource CreateJsonDataSourceFromString()
{
var jsonDataSource = new DashboardJsonDataSource();
string json = "{\"Customers\":[{\"Id\":\"ALFKI\",
\"CompanyName\":\"Alfreds Futterkiste\",\"ContactName\":\"Maria Anders\",
\"ContactTitle\":\"Sales Representative\",\"Address\":\"Obere Str. 57\",
\"City\":\"Berlin\",\"PostalCode\":\"12209\",\"Country\":\"Germany\",
\"Phone\":\"030-0074321\",\"Fax\":\"030-0076545\"}],\"ResponseStatus\":{}}";
jsonDataSource.JsonSource = new CustomJsonSource(json);
jsonDataSource.RootElement = "Customers";
return jsonDataSource;
}