An attribute argument must be a constant expression
Is there any workaround for the following issue?
An attri开发者_如何转开发bute argument must be a constant expression
I want to use decimals in an attribute’s parameter.
Unfortunately you can't use decimals in attribute values, as the CLR itself doesn't really know about System.Decimal
type - it's not a primitive type like int, double etc. The C# compiler basically fakes it for const fields of type decimal, but it can't achieve the same effect with attributes.
From the C# 3 spec, section 17.1.3:
The types of positional and named parameters for an attribute class are limited to the attribute parameter types, which are:
- One of the following types: bool, byte, char, double, float, int, long, sbyte, short, string, uint, ulong, ushort.
- The type object.
- The type System.Type.
- An enum type, provided it has public accessibility and the types in which it is nested (if any) also have public accessibility (§17.2).
- Single-dimensional arrays of the above types.
Then later in section 17.2:
An expression E is an attribute-argument-expression if all of the following statements are > true:
- The type of E is an attribute parameter type (§17.1.3).
- At compile-time, the value of E can be resolved to one of the following:
- A constant value.
- A System.Type object.
- A one-dimensional array of attribute-argument-expressions.
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