MongoDBDataConnection LoadConnection(
    string name
)

Function LoadConnection(
    name As String
) As MongoDBDataConnection

using DevExpress.DataAccess.MongoDB;
using DevExpress.XtraPrinting.Native;
// ...
// Create a new class and implement the IMongoDBConnectionProviderService interface.
public class CustomMongoDBConnectionProviderService : IMongoDBConnectionProviderService {
    // Implement the LoadConnection method. 
    public MongoDBDataConnection LoadConnection(string name) {
        // The first argument of the LoadConnection method stores a string
        // assigned to the ConnectionName property of a MongoDBDataSource object.
        // Use this name to load a connection string from a file.
        // ...

        var connectionString = "...";

        // Create and return a MongoDBDataConnection object.
        return new MongoDBDataConnection(connectionString);
    }
}
// ...
void MongoDBCustomConnectionProvideServiceExample() {
    // Create a MongoDBDataSource object and specify its ConnectionName property.
    // The specified name is passed as an argument to the LoadConnection method of
    // the custom connection service.
    var mongoDBDataSource = new MongoDBDataSource() {
        ConnectionName = "...",
        Queries = { /* ... */ }
    };

    // Register the created custom connection service for the MongoDBDataSource object.
    mongoDBDataSource.AddService<IMongoDBConnectionProviderService>(
        new CustomMongoDBConnectionProviderService()
    );

    // Call the Fill method of the MongoDBDataSource object to execute queries
    // and load data from a MongoDB instance.
    mongoDBDataSource.Fill();

    // Use the created object as a data source in your application or component.
    // ...
}

Imports DevExpress.DataAccess.MongoDB
Imports DevExpress.XtraPrinting.Native
' ...
' Create a new class and implement the IMongoDBConnectionProviderService interface.
Public Class CustomMongoDBConnectionProviderService
    Implements IMongoDBConnectionProviderService

    ' Implement the LoadConnection method. 
    Public Function LoadConnection(name As String) As MongoDBDataConnection Implements IMongoDBConnectionProviderService.LoadConnection
        ' The first argument of the LoadConnection method stores a string
        ' assigned to the ConnectionName property of a MongoDBDataSource object.
        ' Use this name to load a connection string from a file.
        ' ...

        Dim connectionString = "..."

        ' Create and return a MongoDBDataConnection object.
        Return New MongoDBDataConnection(connectionString)
    End Function
End Class
' ...
Private Sub MongoDBCustomConnectionProvideServiceExample()
    ' Create a MongoDBDataSource object and specify its ConnectionName property.
    ' The specified name is passed as an argument to the LoadConnection method of
    ' the custom connection service.
    Dim mongoDBDataSource = New MongoDBDataSource() With {.ConnectionName = "..."}

    ' Add queries to the data source's Queries collection.
    ' ...

    ' Register the created custom connection service for the MongoDBDataSource object.
    mongoDBDataSource.AddService(Of IMongoDBConnectionProviderService)(New CustomMongoDBConnectionProviderService())

    ' Call the Fill method of the MongoDBDataSource object to execute queries
    ' and load data from a MongoDB instance.
    mongoDBDataSource.Fill()

    ' Use the created object as a data source in your application or component.
    ' ...
End Sub