Can I read properties before creating an object? In the constructor?

Question

Is it possible to count the number of properties in a class before creating an object? Can I do this in the constructor?

class MyClass { public string A { get; set; } public string B { get; set; } public string C { get; set; } public MyClass() { int count = //somehow count properties? => 3 } } 

thanks

Answer 1

Yes, you can:

 class MyClass { public string A { get; set; } public string B { get; set; } public string C { get; set; } public MyClass() { int count = this.GetType().GetProperties().Count(); // or count = typeof(MyClass).GetProperties().Count(); } } 

Answer 2

It is possible to use reflection, as shown by BigYellowCactus. But there is no need to do this in the constructor every time, because the number of properties never changes.

I would suggest doing this in a static constructor (called only once for each type):

 class MyClass { public string A{ get; set; } public string B{ get; set; } public string C{ get; set; } private static readonly int _propertyCount; static MyClass() { _propertyCount = typeof(MyClass).GetProperties().Count(); } } 

Answer 3

 public MyClass() { int count = GetType().GetProperties().Count(); } 

Answer 4

Use this to count the number of properties contained in your class.

 Type type = typeof(YourClassName); int NumberOfRecords = type.GetProperties().Length;