Significance of text inside square brackets [duplicate]

Question

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What does square bracket [] mean in the below code? (2 answers)

Closed 9 years ago.

1. Hello, can you please explain me what is the significance of [Microsoft.Xrm.Sdk.AttributeLogicalNameAttribute("activityid")] in the following code?

   [Microsoft.Xrm.Sdk.AttributeLogicalNameAttribute("activityid")]
   public Microsoft.Xrm.Sdk.EntityReference ActivityId
   {
       get
       {
           return this.GetAttributeValue<Microsoft.Xrm.Sdk.EntityReference>("activityid");
       }
       set
       {
           this.OnPropertyChanging("ActivityId");
           this.SetAttributeValue("activityid", value);
           this.OnPropertyChanged("ActivityId");
       }
   }
   

   I searched for this thing and I got many posts which gave me answer as the ones in square brackets are Attributes in C#. But, then attributes are related with methods. Over here, ActivityId doesn't seem to be a method. So, how can [Microsoft.Xrm.Sdk.AttributeLogicalNameAttribute("activityid")] act as an attribute?

2. Is it related to C# or it has got something to do with CRM?

Answer 1

The confusion comes from your statement about attributes only being valid on methods. Attributes can be valid on items specified in the AttributeTargets enum:

http://msdn.microsoft.com/en-us/library/system.attributetargets.aspx

This then puts you back to the answer being "they are attributes". That attribute has simply been applied to a property.