public FunctionMapping(
	Type definingType,
	string functionName,
	int parameterCount,
	string dbFunctionCallPattern
)

Public Sub New ( 
	definingType As Type,
	functionName As String,
	parameterCount As Integer,
	dbFunctionCallPattern As String
)

Parameters

definingType

Type: SystemType
The defining type of the function, e.g. typeof(System.String).

functionName

Type: SystemString
Name of the .NET function or operator (in string form, e.g. "+") which equivalent should be called. Example: Concat. Is part of unique key for this functionmapping

parameterCount

Type: SystemInt32
The parameter count of the function / operator. This number has to be equal to the # of parameters of the db equivalent. Is part of unique key for this function mapping

dbFunctionCallPattern

Type: SystemString
The DbFunctionCall pattern to use, which is the pattern used in the DbFunctionCall object which will take care of the function call text in the resulting query.

Reference