对标 System.Linq.Expressions的ExpressionType，使用Enum.TryParse进行处理，代码如下
if (Enum.TryParse(rule.Operator, out ExpressionType nestedOperator) && nestedOperators.Contains(nestedOperator) &&
rule.Rules != null && rule.Rules.Any())
{
ruleFn = BuildNestedRuleFunc(rule, nestedOperator, extendedRuleParams);
}
else
{
ruleFn = BuildRuleFunc(rule, extendedRuleParams);
}
ExpressionType参考如下：
public enum ExpressionType
{
//
// 摘要:
// An addition operation, such as a + b, without overflow checking, for numeric
// operands.
Add = 0,
//
// 摘要:
// An addition operation, such as (a + b), with overflow checking, for numeric operands.
AddChecked = 1,
//
// 摘要:
// A bitwise or logical AND operation, such as (a & b) in C# and (a And b) in Visual
// Basic.
And = 2,
//
// 摘要:
// A conditional AND operation that evaluates the second operand only if the first
// operand evaluates to true. It corresponds to (a && b) in C# and (a AndAlso b)
// in Visual Basic.
AndAlso = 3,
//
// 摘要:
// An operation that obtains the length of a one-dimensional array, such as array.Length.
ArrayLength = 4,
//
// 摘要:
// An indexing operation in a one-dimensional array, such as array[index] in C#
// or array(index) in Visual Basic.
ArrayIndex = 5,
//
// 摘要:
// A method call, such as in the obj.sampleMethod() expression.
Call = 6,
//
// 摘要:
// A node that represents a null coalescing operation, such as (a ?? b) in C# or
// If(a, b) in Visual Basic.
Coalesce = 7,
//
// 摘要:
// A conditional operation, such as a > b ? a : b in C# or If(a > b, a, b) in Visual
// Basic.
Conditional = 8,
//
// 摘要:
// A constant value.
Constant = 9,
//
// 摘要:
// A cast or conversion operation, such as (SampleType)obj in C#or CType(obj, SampleType)
// in Visual Basic. For a numeric conversion, if the converted value is too large
// for the destination type, no exception is thrown.
Convert = 10,
//
// 摘要:
// A cast or conversion operation, such as (SampleType)obj in C#or CType(obj, SampleType)
// in Visual Basic. For a numeric conversion, if the converted value does not fit
// the destination type, an exception is thrown.
ConvertChecked = 11,
//
// 摘要:
// A division operation, such as (a / b), for numeric operands.
Divide = 12,
//
// 摘要:
// A node that represents an equality comparison, such as (a == b) in C# or (a =
// b) in Visual Basic.
Equal = 13,
//
// 摘要:
// A bitwise or logical XOR operation, such as (a ^ b) in C# or (a Xor b) in Visual
// Basic.
ExclusiveOr = 14,
//
// 摘要:
// A "greater than" comparison, such as (a > b).
GreaterThan = 15,
//
// 摘要:
// A "greater than or equal to" comparison, such as (a >= b).
GreaterThanOrEqual = 16,
//
// 摘要:
// An operation that invokes a delegate or lambda expression, such as sampleDelegate.Invoke().
Invoke = 17,
//
// 摘要:
// A lambda expression, such as a => a + a in C# or Function(a) a + a in Visual
// Basic.
Lambda = 18,
//
// 摘要:
// A bitwise left-shift operation, such as (a << b).
LeftShift = 19,
//
// 摘要:
// A "less than" comparison, such as (a < b).
LessThan = 20,
//
// 摘要:
// A "less than or equal to" comparison, such as (a <= b).
LessThanOrEqual = 21,
//
// 摘要:
// An operation that creates a new System.Collections.IEnumerable object and initializes
// it from a list of elements, such as new List(){ a, b, c } in C# or Dim sampleList
// = { a, b, c } in Visual Basic.
ListInit = 22,
//
// 摘要:
// An operation that reads from a field or property, such as obj.SampleProperty.
MemberAccess = 23,
//
// 摘要:
// An operation that creates a new object and initializes one or more of its members,
// such as new Point { X = 1, Y = 2 } in C# or New Point With {.X = 1, .Y = 2} in
// Visual Basic.
MemberInit = 24,
//
// 摘要:
// An arithmetic remainder operation, such as (a % b) in C# or (a Mod b) in Visual
// Basic.
Modulo = 25,
//
// 摘要:
// A multiplication operation, such as (a * b), without overflow checking, for numeric
// operands.
Multiply = 26,
//
// 摘要:
// An multiplication operation, such as (a * b), that has overflow checking, for
// numeric operands.
MultiplyChecked = 27,
//
// 摘要:
// An arithmetic negation operation, such as (-a). The object a should not be modified
// in place.
Negate = 28,
//
// 摘要:
// A unary plus operation, such as (+a). The result of a predefined unary plus operation
// is the value of the operand, but user-defined implementations might have unusual
// results.
UnaryPlus = 29,
//
// 摘要:
// An arithmetic negation operation, such as (-a), that has overflow checking. The
// object a should not be modified in place.
NegateChecked = 30,
//
// 摘要:
// An operation that calls a constructor to create a new object, such as new SampleType().
New = 31,
//
// 摘要:
// An operation that creates a new one-dimensional array and initializes it from
// a list of elements, such as new SampleType[]{a, b, c} in C# or New SampleType(){a,
// b, c} in Visual Basic.
NewArrayInit = 32,
//
// 摘要:
// An operation that creates a new array, in which the bounds for each dimension
// are specified, such as new SampleType[dim1, dim2] in C# or New SampleType(dim1,
// dim2) in Visual Basic.
NewArrayBounds = 33,
//
// 摘要:
// A bitwise complement or logical negation operation. In C#, it is equivalent to
// (~a) for integral types and to (!a) for Boolean values. In Visual Basic, it is
// equivalent to (Not a). The object a should not be modified in place.
Not = 34,
//
// 摘要:
// An inequality comparison, such as (a != b) in C# or (a <> b) in Visual Basic.
NotEqual = 35,
//
// 摘要:
// A bitwise or logical OR operation, such as (a | b) in C# or (a Or b) in Visual
// Basic.
Or = 36,
//
// 摘要:
// A short-circuiting conditional OR operation, such as (a || b) in C# or (a OrElse
// b) in Visual Basic.
OrElse = 37,
//
// 摘要:
// A reference to a parameter or variable that is defined in the context of the
// expression. For more information, see System.Linq.Expressions.ParameterExpression.
Parameter = 38,
//
// 摘要:
// A mathematical operation that raises a number to a power, such as (a ^ b) in
// Visual Basic.
Power = 39,
//
// 摘要:
// An expression that has a constant value of type System.Linq.Expressions.Expression.
// A System.Linq.Expressions.ExpressionType.Quote node can contain references to
// parameters that are defined in the context of the expression it represents.
Quote = 40,
//
// 摘要:
// A bitwise right-shift operation, such as (a >> b).
RightShift = 41,
//
// 摘要:
// A subtraction operation, such as (a - b), without overflow checking, for numeric
// operands.
Subtract = 42,
//
// 摘要:
// An arithmetic subtraction operation, such as (a - b), that has overflow checking,
// for numeric operands.
SubtractChecked = 43,
//
// 摘要:
// An explicit reference or boxing conversion in which null is supplied if the conversion
// fails, such as (obj as SampleType) in C# or TryCast(obj, SampleType) in Visual
// Basic.
TypeAs = 44,
//
// 摘要:
// A type test, such as obj is SampleType in C# or TypeOf obj is SampleType in Visual
// Basic.
TypeIs = 45,
//
// 摘要:
// An assignment operation, such as (a = b).
Assign = 46,
//
// 摘要:
// A block of expressions.
Block = 47,
//
// 摘要:
// Debugging information.
DebugInfo = 48,
//
// 摘要:
// A unary decrement operation, such as (a - 1) in C# and Visual Basic. The object
// a should not be modified in place.
Decrement = 49,
//
// 摘要:
// A dynamic operation.
Dynamic = 50,
//
// 摘要:
// A default value.
Default = 51,
//
// 摘要:
// An extension expression.
Extension = 52,
//
// 摘要:
// A "go to" expression, such as goto Label in C# or GoTo Label in Visual Basic.
Goto = 53,
//
// 摘要:
// A unary increment operation, such as (a + 1) in C# and Visual Basic. The object
// a should not be modified in place.
Increment = 54,
//
// 摘要:
// An index operation or an operation that accesses a property that takes arguments.
Index = 55,
//
// 摘要:
// A label.
Label = 56,
//
// 摘要:
// A list of run-time variables. For more information, see System.Linq.Expressions.RuntimeVariablesExpression.
RuntimeVariables = 57,
//
// 摘要:
// A loop, such as for or while.
Loop = 58,
//
// 摘要:
// A switch operation, such as switch in C# or Select Case in Visual Basic.
Switch = 59,
//
// 摘要:
// An operation that throws an exception, such as throw new Exception().
Throw = 60,
//
// 摘要:
// A try-catch expression.
Try = 61,
//
// 摘要:
// An unbox value type operation, such as unbox and unbox.any instructions in MSIL.
Unbox = 62,
//
// 摘要:
// An addition compound assignment operation, such as (a += b), without overflow
// checking, for numeric operands.
AddAssign = 63,
//
// 摘要:
// A bitwise or logical AND compound assignment operation, such as (a &= b) in C#.
AndAssign = 64,
//
// 摘要:
// An division compound assignment operation, such as (a /= b), for numeric operands.
DivideAssign = 65,
//
// 摘要:
// A bitwise or logical XOR compound assignment operation, such as (a ^= b) in C#.
ExclusiveOrAssign = 66,
//
// 摘要:
// A bitwise left-shift compound assignment, such as (a <<= b).
LeftShiftAssign = 67,
//
// 摘要:
// An arithmetic remainder compound assignment operation, such as (a %= b) in C#.
ModuloAssign = 68,
//
// 摘要:
// A multiplication compound assignment operation, such as (a *= b), without overflow
// checking, for numeric operands.
MultiplyAssign = 69,
//
// 摘要:
// A bitwise or logical OR compound assignment, such as (a |= b) in C#.
OrAssign = 70,
//
// 摘要:
// A compound assignment operation that raises a number to a power, such as (a ^=
// b) in Visual Basic.
PowerAssign = 71,
//
// 摘要:
// A bitwise right-shift compound assignment operation, such as (a >>= b).
RightShiftAssign = 72,
//
// 摘要:
// A subtraction compound assignment operation, such as (a -= b), without overflow
// checking, for numeric operands.
SubtractAssign = 73,
//
// 摘要:
// An addition compound assignment operation, such as (a += b), with overflow checking,
// for numeric operands.
AddAssignChecked = 74,
//
// 摘要:
// A multiplication compound assignment operation, such as (a *= b), that has overflow
// checking, for numeric operands.
MultiplyAssignChecked = 75,
//
// 摘要:
// A subtraction compound assignment operation, such as (a -= b), that has overflow
// checking, for numeric operands.
SubtractAssignChecked = 76,
//
// 摘要:
// A unary prefix increment, such as (++a). The object a should be modified in place.
PreIncrementAssign = 77,
//
// 摘要:
// A unary prefix decrement, such as (--a). The object a should be modified in place.
PreDecrementAssign = 78,
//
// 摘要:
// A unary postfix increment, such as (a++). The object a should be modified in
// place.
PostIncrementAssign = 79,
//
// 摘要:
// A unary postfix decrement, such as (a--). The object a should be modified in
// place.
PostDecrementAssign = 80,
//
// 摘要:
// An exact type test.
TypeEqual = 81,
//
// 摘要:
// A ones complement operation, such as (~a) in C#.
OnesComplement = 82,
//
// 摘要:
// A true condition value.
IsTrue = 83,
//
// 摘要:
// A false condition value.
IsFalse = 84
}
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