How to expand OLAP Grid and OLAP Chart in OLAP Client upto "n" level initially?

    OlapReport olapReport = new OlapReport();
    olapReport.CurrentCubeName = "Adventure Works";
    DimensionElement dimensionElement = new DimensionElement() { Name = "Product" };
    dimensionElement.AddLevel("Product Categories", "Category");
    olapReport.SeriesElements.Add(dimensionElement);
    dimensionElement = new DimensionElement() { Name = "Date" };
    dimensionElement.AddLevel("Fiscal", "Fiscal Year");
    dimensionElement.DrillState = DrillState.ExpandToLevel;
    dimensionElement.DrillUpDownLevel = "Month";
    olapReport.CategoricalElements.Add(dimensionElement);
    return olapReport;

                Dim olapReport As OlapReport = New OlapReport()
                olapReport.CurrentCubeName = "Adventure Works"
                Dim dimensionElement As DimensionElement = New DimensionElement() With {.Name = "Product"}
                dimensionElement.AddLevel("Product Categories", "Category")
                olapReport.SeriesElements.Add(dimensionElement)
                Dim TempDimensionElement As DimensionElement = New DimensionElement() With {.Name = "Date"}
                dimensionElement = New DimensionElement() With {.Name
                dimensionElement.AddLevel("Fiscal", "Fiscal Year")
                dimensionElement.DrillState = DrillState.ExpandToLevel
                dimensionElement.DrillUpDownLevel = "Month"
                olapReport.CategoricalElements.Add(dimensionElement)
                Return olapReport