dashboard-401312-winforms-dashboard-winforms-designer-create-dashboards-in-the-winforms-designer-providing-data-json-data-source.md
The Dashboard Designer allows you to connect to a JSON data source that retrieves data from a Web-service endpoint, 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.
Follow the steps below to connect to the JSON data source:
Click the New Data Source button in the Data Source ribbon tab.
On the first page of the invoked Data Source Wizard dialog, specify whether you want to use an existing data connection or create a new data connection.
On the next page, select JSON data and click Next.
View Example: How to Bind a Dashboard to the JSON Data Source at Runtime
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;
}
Imports DevExpress.DashboardCommon
Imports DevExpress.DataAccess.Json
' ...
Public Sub InitializeDashboard()
Dim dashboard As New Dashboard()
Dim jsonDataSourceFromWeb As DashboardJsonDataSource = CreateJsonDataSourceFromWeb()
Dim jsonDataSourceFromFile As DashboardJsonDataSource = CreateJsonDataSourceFromFile()
Dim jsonDataSourceFromString As DashboardJsonDataSource = CreateJsonDataSourceFromString()
dashboard.DataSources.Add(jsonDataSourceFromWeb)
dashboard.DataSources.Add(jsonDataSourceFromFile)
dashboard.DataSources.Add(jsonDataSourceFromString)
End Sub
Public Shared Function CreateJsonDataSourceFromWeb() As DashboardJsonDataSource
Dim 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
End Function
Public Shared Function CreateJsonDataSourceFromFile() As DashboardJsonDataSource
Dim jsonDataSource = New DashboardJsonDataSource()
Dim fileUri As New Uri("customers.json", UriKind.RelativeOrAbsolute)
jsonDataSource.JsonSource = New UriJsonSource(fileUri)
jsonDataSource.RootElement = "Customers"
Return jsonDataSource
End Function
Public Shared Function CreateJsonDataSourceFromString() As DashboardJsonDataSource
Dim jsonDataSource = New DashboardJsonDataSource()
Dim json As String = "{""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
End Function
See Also