A property or indexer may not be passed as an out

Question

I am getting the above error and unable to resolve it. I googled a bit but can't get rid of it.

Scenario:

I have class BudgetAllocate whose property is budget which is of double type.

In my dataAccessLayer,

In one of my classes I am trying to do this:

double.TryParse(objReader[i].ToString(), out bd.Budget);

Which is throwing this error:

Property or indexer may not be passed as an out or ref parameter at compile time.

I even tried this:

double.TryParse(objReader[i].ToString().Equals(DBNull.Value) ? "" : objReader[i].ToString(), out bd.Budget);

Everything else is working fine and references between layers are present.

Answer 1

Others have given you the solution, but as to why this is necessary: a property is just syntactic sugar for a method.

For example, when you declare a property called Name with a getter and setter, under the hood the compiler actually generates methods called get_Name() and set_Name(value). Then, when you read from and write to this property, the compiler translates these operations into calls to those generated methods.

When you consider this, it becomes obvious why you can't pass a property as an output parameter - you would actually be passing a reference to a method, rather than a reference to an object a variable, which is what an output parameter expects.

A similar case exists for indexers.