public static IEnumerable<IDataSourceAssignable> GetDataSourceAssignablesByDataSource(
    XtraReport report,
    object dataSource,
    bool includeSubReports = false
)

Public Shared Function GetDataSourceAssignablesByDataSource(
    report As XtraReport,
    dataSource As Object,
    includeSubReports As Boolean = False
) As IEnumerable(Of IDataSourceAssignable)

using DevExpress.XtraReports;
//...

var report = new XtraReport1();

var dataSourceAssignables = DataSourceManager.GetDataSourceAssignablesByDataSource(
    report,
    report.DataSource,
    includeSubReports: true
);

foreach (var elements in dataSourceAssignables) {
    // Process report elements here... 
}

Imports DevExpress.XtraReports
'...

Private report = New XtraReport1()

Private dataSourceAssignables = DataSourceManager.GetDataSourceAssignablesByDataSource(report, report.DataSource, includeSubReports:= True)

For Each elements In dataSourceAssignables
    ' Process report elements here... 
Next elements