OK I figured out what I think is a reasonable way to do this. I'd like to share it to hopefully spare others the same pain. Hope it helps!

The key is using DimensionMetadata objects (to which the key is the CubeMatada.DataTypeFullName property -- it MUST be set to the same value as DynamicTypeBuilder.DynamicTypeName (i.e. the type name of the objects in the ItemsSource); see http://es.infragistics.com/community/forums/p/83388/416871.aspx#416871) and adding the HierarchyDescriptors to them. When doing it this way you can use the AddLevel<DateTime> method to add levels to the hierarchies and still use method calls in the Lambda expressions. This way also lets you customize the display of each property. Just what I was looking for!

Note: in the example below, "dt" is the original DataTable that the list of dynamic objects was built from.

            flatDataSource.DimensionsGenerationMode = DimensionsGenerationMode.Mixed;
 
            CubeMetadata cubeMetadata = new CubeMetadata();
            cubeMetadata.DisplayName = dt.TableName;
            cubeMetadata.DataTypeFullName = dt.TableName;  // Same as DynamicTypeName
 
            foreach (DataColumn col in dt.Columns)
            {
                DimensionMetadata dm = new DimensionMetadata()
                {
                    SourcePropertyName = col.ColumnName,
                    DisplayName = col.Caption,
                };
 
                if (col.DataType == typeof(DateTime))
                {
                    HierarchyDescriptor dateTimeDescriptor = new HierarchyDescriptor
                    {
                        AppliesToPropertiesOfType = typeof(DateTime)
                    };
                    string allString = "All " + col.Caption + "s";
                    dateTimeDescriptor.AddLevel<DateTime>(date => allString, allString);
                    dateTimeDescriptor.AddLevel<DateTime>(date => date.Year, "Years");
                    dateTimeDescriptor.AddLevel<DateTime>(date => date.QuarterShort(), "Quarters");
                    dateTimeDescriptor.AddLevel<DateTime>(date => date.MonthShort(), "Months");
                    dateTimeDescriptor.AddLevel<DateTime>(date => date.Date.ZenithDateString(), "Dates");
                    dm.HierarchyDescriptors.Add(dateTimeDescriptor);
                }
                else
                {
                    HierarchyDescriptor hier = new HierarchyDescriptor
                    {
                        SourcePropertyName = col.ColumnName,
                        HierarchyName = col.Caption,
                        HierarchyDisplayName = col.Caption
                    };
 
                    HierarchyLevelDescriptor allLevel = new HierarchyLevelDescriptor
                    {
                        LevelName = "All " + col.Caption + "s"
                    };
                    hier.LevelDescriptors.Add(allLevel);
 
                    HierarchyLevelDescriptor entriesLevel = new HierarchyLevelDescriptor
                    {
                        LevelName = col.Caption,
                        LevelExpressionPath = col.ColumnName
                    };
                    if (col.DataType == typeof(decimal))
                        entriesLevel.DisplayFormat = "C2";
                    hier.LevelDescriptors.Add(entriesLevel);
 
                    dm.HierarchyDescriptors.Add(hier);
                }
                cubeMetadata.DimensionSettings.Add(dm);
            }

OK... Perhaps you can clear up a few things that are confusing to my decidedly non-expert mind...

1) Pardon my ignorance here, but isn't a Lambda expression essentially a way for me to pass you "code" to execute, without you really knowing what it is or does, as long as it takes the correct parameters and returns something reasonable? If so, then why do you care whether the code I pass references a property or method? Clearly you said that you do care, but I'd really like to understand why, because it makes no sense to me...

2) Is this behavior intentional (i.e. "feature" or "Bug" :-) )?

3) If the AddLevel<DateTime> method, which takes a Lambda expression, supports method calls, why doesn't setting the expression directly on a HierarchyLevelDescritpor support it? That also makes no sense to me as an outsider looking in...

4) Can you please consider this a feature request?

Thanks,

Bob

Hello, 

LevelExpression and LevelExpressionPath are properties that could be added to set the path which is used for resolving data from particular instance. The LevelExpression allows you to set the path as lambda expression. If you are using the LevelExpressionPath, there is no need to set the LevelExpression, too. Plamen suggested a custom approach that could help you achieve the functionality you need as these properties do not support method calls (“.QuarterShort()” in the provided code snippet). Using a property that provides the value returned by QuarterShort will allow you to set the LevelExpressionPath to the HierarchyLevelDescriptor.

Please feel free to let us know fi you have any other questions on this.

Thanks, Plamen, I'll have a look.

But is there no way to do it with LevelExpression? Can you please give an example of how one would use that property (to do anything)?

The fact that you can do something like dateTimeDescriptor.AddLevel<DateTime>(date => date.QuarterShort(), "Quarters");  when using "AppliesToPropertiesOfType" (which apparently doesn't allow you to customize things for specific properties, only set behavior for all properties of a given type) implies to me that there must be a way to do something similar on a particular property...

I feel like I'm missing something...

Thanks,

Bob