public display DimensionValue showCostCenter(CustTable _custTable)
{
    DimensionAttributeValueSet dimensionAttributeValueSet;
    DimensionAttributeValueSetItem dimensionAttributeValueSetItem;
    DimensionAttributeValue dimensionAttributeValue;
    DimensionAttribute dimensionAttribute;

    #define.CostCenterDimensionName("CostCenter");
 
    if( !_custTable || !_custTable.DefaultDimension)
    {
        return '';
    } 

    dimensionAttributeValueSet = DimensionAttributeValueSet::find(_custTable.DefaultDimension); 

    select firstOnly RecId
    from dimensionAttributeValueSetItem
        where dimensionAttributeValueSetItem.DimensionAttributeValueSet == dimensionAttributeValueSet.RecId
    join DimensionAttributeValue
        where DimensionAttributeValue.RecId == dimensionAttributeValueSetItem.DimensionAttributeValue
    join RecId from dimensionAttribute
    where dimensionAttribute.RecId == DimensionAttributeValue.DimensionAttribute
       && dimensionAttribute.Name  == #CostCenterDimensionName
    

    if(dimensionAttributeValue && dimensionAttribute)
    {
        return dimensionAttributeValue.getValue();
    }

    return '';
}

Einfachere Variante (siehe Kommentare)

public display DimensionValue showCostCenter(CustTable _custTable)
{
    #define.CostCenterDimensionName("CostCenter");
 
    return ((select firstOnly DisplayValue from DefaultDimensionView
             where DefaultDimensionView.Name == #CostCenterDimensionName
                && DefaultDimensionView.DefaultDimension == _custTable.DefaultDimension).DisplayValue);
}