As a reference, here is the KB describing the custom code that is allowed for use in Microsoft Dynamics CRM Online FetchXML Reports:
http://support.microsoft.com/kb/2600639/en-us
When RDL Sandboxing is enabled, only certain classes and methods can be used in a custom FetchXML report. The following is a list of the classes that are allowed, and beneath each class are the available methods for use in Microsoft Dynamics CRM Online reports:
1.Microsoft.VisualBasic.Interaction (For more information, see: Interaction)
- IIF
- Partition
- ToString
2.Microsoft.VisualBasic.Information (For more information, see: Information)
- IsArray
- IsDate
- IsNothing
- IsNumeric
- IsReference
- QBColor
- RGB
- ToString
- TypeName
- VarType
3.Microsoft.VisualBasic.Strings (For more information, see: Strings)
- Asc
- AscW
- Chr
- ChrW
- Format
- FormatCurrency
- FormatDateTime
- FormatNumber
- FormatPercent
- InStr
- InStrRev
- Join
- Lcase
- Left
- Len
- LTrim
- Mid
- Replace
- Right
- RTrim
- Space
- Split
- StrComp
- StrReverse
- ToString
- Trim
- UCase
4.Microsoft.VisualBasic.DateInterval (For more information, see: DateInterval)
- Year
- Quarter
- Month
- Day
- WeekOfYear
- WeekDay
- Hour
- Minute
- Second
5.Microsoft.VisualBasic.DateAndTime (For more information, see: DateAndTime)
- DateAdd
- DateDiff
- DateValue
- Day
- Hour
- Minute
- Month
- MonthName
- Second
- DatePart
- DateSerial
- TimeSerial
- TimeValue
- ToString
- Weekday
- WeekdayName
- Year
6.Microsoft.VisualBasic.Financial (For more information, see: Financial)
- DDB
- FV
- IPmt
- NPer
- Pmt
- PPmt
- PV
- Rate
- SLN
- SYD
- ToString
7.Microsoft.VisualBasic.Conversion (For more information, see: Conversion)
- CTypeDynamic
- Hex
- Oct
- Str
- ToString
- Val
8.System.DbNull (For more information, see: DBNull)
- GetObjectData
- ToString
9.System.Globalization.CultureInfo (For more information, see: CultureInfo)
- ClearCachedData
- Clone
- CreateSpecificCulture
- GetConsoleFallbackUICulture
- GetCultureInfo
- GetCultureInfoByLeftLanguageTag
- GetCultures
- GetFormat
- ReadOnly
- ToString
10.System.Math (For more information, see: Math)
- Abs
- Atan
- Cos
- Exp
- Floor
- Log
- Log10
- Max
- Min
- Round
- Sign
- Sin
- Sqrt
- Tan
11.System.String (For more information, see: String)
- Clone
- CompareOrdinal
- Concat
- Contains
- Copy
- CopyTo
- EndsWith
- Format
- GetEnumerator
- IndexOf
- IndexOfAny
- Insert
- Intern
- IsInterned
- IsNormalized
- IsNullOrEmpty
- IsNullOrWhiteSpace
- Join
- LastIndexOf
- LastIndexOfAny
- Normalize
- PadLeft
- PadRight
- Split
- StartsWith
- Substring
- ToCharArray
- ToLower
- ToLowerInvariant
- ToString
- ToUpper
- ToUpperInvariant
- Trim
- TrimEnd
- TrimStart
12.System.Text.RegularExpressions.Match (For more information, see: Match)
- ToString
13.System.Text.RegularExpressions.Regex (For more information, see: Regex)
- Match
- Replace
- Split
- ToString