[DefaultValue(null)]
public Uri Uri { get; set; }

<DefaultValue(Nothing)>
Public Property Uri As Uri

using DevExpress.DataAccess.Json;
using DevExpress.XtraReports.UI;
public static JsonDataSource CreateDataSourceFromWeb() {
    var jsonDataSource = new JsonDataSource();
    // Specify the endpoint.
    jsonDataSource.JsonSource = new UriJsonSource(
        new Uri("https://raw.githubusercontent.com/DevExpress-Examples/DataSources/master/JSON/customers.json"));
var root = new JsonSchemaNode();
root.NodeType = JsonNodeType.Object;

var customers = new JsonSchemaNode() {NodeType=JsonNodeType.Array, Name="Customers", Selected=true };
customers.AddChildren(new[] {
    new JsonSchemaNode(new JsonNode("CustomerID", true,
    JsonNodeType.Property, typeof(string))) 
    { 
    DisplayName = "Customer ID" },
    new JsonSchemaNode() {
        Name = "CompanyName",
        Selected = true,
        NodeType = JsonNodeType.Property,
        Type = typeof(string)
    },
    new JsonSchemaNode(new JsonNode("ContactTitle", true, JsonNodeType.Property, typeof(string))),
    new JsonSchemaNode(new JsonNode("Address", false, JsonNodeType.Property, typeof(string)))
});

root.AddChildren(customers);
jsonDataSource.Schema = root;
            // The schema is built, you do not have to call the Fill method to populate the Field List.
            // The Designer calls the Fill method automatically when a document is generated for preview.
            //jsonDataSource.Fill();
            return jsonDataSource;
        }

Imports System.Net
Imports DevExpress.DataAccess.Json
Imports DevExpress.XtraReports.UI
Public Shared Function CreateDataSourceFromWeb() As JsonDataSource
    Dim jsonDataSource = New JsonDataSource()
    ' Specify the endpoint.
    jsonDataSource.JsonSource = New UriJsonSource(
        New Uri("https://raw.githubusercontent.com/DevExpress-Examples/DataSources/master/JSON/customers.json"))
Dim root = New JsonSchemaNode()
root.NodeType = JsonNodeType.Object

Dim customers = New JsonSchemaNode() With {.NodeType = JsonNodeType.Array, .Name = "Customers", .Selected = True}
customers.AddChildren({
    New JsonSchemaNode(New JsonNode("CustomerID", True, JsonNodeType.Property,
                                    GetType(String))) With {.DisplayName = "Customer ID"},
    New JsonSchemaNode() With {.Name = "CompanyName", .Selected = True,
    .NodeType = JsonNodeType.Property, .Type = GetType(String)},
    New JsonSchemaNode(New JsonNode("ContactTitle", True, JsonNodeType.Property,
                                    GetType(String))),
    New JsonSchemaNode(New JsonNode("Address", False, JsonNodeType.Property,
                                    GetType(String)))
})

root.AddChildren(customers)
jsonDataSource.Schema = root
            ' The schema is built, you do not have to call the Fill method to populate the Field List.
            ' The Designer calls the Fill method automatically when a document is generated for preview.
            'jsonDataSource.Fill()
            Return jsonDataSource
        End Function

using DevExpress.DataAccess.Json;
using DevExpress.XtraReports.UI;
public static JsonDataSource CreateDataSourceFromFile() {
    var jsonDataSource = new JsonDataSource();
    // Specify the JSON file name.
    Uri fileUri = new Uri("customers.json", UriKind.RelativeOrAbsolute);
    jsonDataSource.JsonSource = new UriJsonSource(fileUri);
    // Populate the data source with data.
    jsonDataSource.Fill();
    return jsonDataSource;
}

Imports System.Net
Imports DevExpress.DataAccess.Json
Imports DevExpress.XtraReports.UI
Public Shared Function CreateDataSourceFromFile() As JsonDataSource
    Dim jsonDataSource = New JsonDataSource()
    ' Specify the JSON file name.
    Dim fileUri As New Uri("customers.json", UriKind.RelativeOrAbsolute)
    jsonDataSource.JsonSource = New UriJsonSource(fileUri)
    ' Populate the data source with data.
    jsonDataSource.Fill()
    Return jsonDataSource
End Function

var jsonSource = new DevExpress.DataAccess.Json.UriJsonSource();
jsonSource.Uri = new Uri(@"http://northwind.servicestack.net/customers.json");

UriJsonSource uriSource = (e.ConnectionParameters as JsonSourceConnectionParameters).JsonSource as UriJsonSource;
    uriSource.Uri = new Uri(HostingEnvironment.MapPath(@"~/App_Data/Categories.json"), UriKind.RelativeOrAbsolute);
}

Dim jsonSource = New DevExpress.DataAccess.Json.UriJsonSource()
jsonSource.Uri = New Uri("http://northwind.servicestack.net/customers.json")

Dim uriSource As UriJsonSource = TryCast((TryCast(e.ConnectionParameters, JsonSourceConnectionParameters)).JsonSource, UriJsonSource)
    uriSource.Uri = New Uri(HostingEnvironment.MapPath("~/App_Data/Categories.json"), UriKind.RelativeOrAbsolute)
End If