How to set attributes values using reflection

Question

Hi,

I have a class decorated with a attribute ...[DataEntity("MESSAGE_STAGING", EnableCaching = true, CacheTimeout = 43200)]

for some requirement,I want to change this value "MESSAGE_STAGING" at run time to "Test_Message_Staging" .

What is the best possible way to achieve this?

Can i use reflection ,Or is there any other way to do this.

Please provide code samples.

Thanks SNA

Answer 1

I don't believe it's possible to set attributes using reflection - and even if it is, I'd encourage you not to do so.

Attributes should be used for metadata which is known at compile-time. If you want a more dynamic form of metadata, load it from a file or use app.config instead... or at least have some special "placeholder" values (like |DataDirectory| in a connection string) which can be resolved at execution time.

Answer 2

It's not possible to change attribute property value at run-time with reflection because attributes are meta-data serialized in the assembly and changing them means changing the assembly.

Answer 3

Hi,

If i understand you correctly, there is a possible way in reflection to change the attribute value of a instance at runtime.. checkout the sample code

        AttributeCollection ac  = TypeDescriptor.GetAttributes(yourObj);

        foreach (var att in ac)
        {
            //DataEntityAttribute  -- ur attribute class name
            DataEntityAttribute da = att as DataEntityAttribute ;
            Console.WriteLine(da.field1);  //initially it shows MESSAGE_STAGING
            da.field1= "Test_Message_Staging";  
         }


         //Check the changed value
        AttributeCollection acc = TypeDescriptor.GetAttributes(yourObj);

        foreach (var att in ac)
        {
            DataEntityAttribute da = att as DataEntityAttribute ;
            Console.WriteLine(da.field1); //now it shows Test_Message_Staging
        }

Cheers

RameshVel