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SNA
SNA

Reputation: 7728

How to set attributes values using reflection

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

Upvotes: 9

Views: 11804

Answers (3)

Branislav Abadjimarinov
Branislav Abadjimarinov

Reputation: 5131

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.

Upvotes: 5

RameshVel
RameshVel

Reputation: 65877

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
        }

Upvotes: 1

Jon Skeet
Jon Skeet

Reputation: 1500605

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.

Upvotes: 9

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