Passing enum/ compiled value as a parameter to constructor

Question

At the moment I am writing my own ValidationAttribute for my mvc application.

I have following ValidationAttribute code.

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Class | AttributeTargets.Parameter, AllowMultiple = false)] 
public class RecordAttribute: ValidationAttribute
{

   public UniqueDataRecordAttribute(string primaryKeyProperty)
   {

   }
}

I pass the field name of my primary property as a string to my attribute and make sone validation. E.g.:

[RecordAttribute("CustomerID")]
public class CustomerMetaData
{


}

This works for me, but I will run into problems if the name of the primary key will change.

I created a enum which contains the primary key attribute. But when I try to pass it the compiler is telling me:

An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type

I also tried this approach: Associating enums with strings in C# but the effect is the same.

Is there any chance to pass a enum (or other compiled value) to my attribute?

Thank you

Why would the name of the primary key change. That sort of thing you fix in place so it doesn't change....? — Matthew Abbott, Apr 26 '12 at 07:11

score 0 · Accepted Answer · answered Apr 26 '12 at 07:09

Are you trying to do something like this?

[RecordAttribute(Keys.CustomerID.ToString())] 
public class CustomerMetaData 
{ 
}

That won't work because the string returned by Keys.CustomerID.ToString() isn't a constant.

Instead of an enum could you use a static class of const string fields?

static class Keys {
  public const string CustomerID = "CustomerID";
}

Then this will work:

[RecordAttribute(Keys.CustomerID)] 
public class CustomerMetaData 
{ 
}

Passing enum/ compiled value as a parameter to constructor

1 Answers1