Multiple AttributeTargets in AttributeUsage

Question

[AttributeUsage(AttributeTargets.Property)]
public class MyAttribute : Attribute
{
...
}

I want this custom attribute used both on properties and fileds but not others. How do I assign multiple targets(AttributeTargets.Property and AttributeTargets.Field)? Or It's just not possible?

And AttributeTargets.All is not what I want.

Answer 1

You can specify multiple targets like this, by using the | (bitwise OR) operator to specify multiple enum values:

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field)]
public class MyAttribute : Attribute
{
    ...
}

The bitwise OR operator works with the AttributeTargets enum because its values are assigned a particular way and it's marked with the Flags attribute.

If you care to, you can read more here:

• C# Fundamentals: Combining Enum Values with Bit-Flags
• Understand how bitwise operators work (C# and VB.NET examples)