Is there a way to set properties on struct instances using reflection?

c# reflection propertyinfo
Victor Chelaru picture Victor Chelaru · Jun 8, 2011 · Viewed 12.1k times · Source

I'm trying to write some code that sets a property on a struct (important that it's a property on a struct) and it's failing:

System.Drawing.Rectangle rectangle = new System.Drawing.Rectangle();
PropertyInfo propertyInfo = typeof(System.Drawing.Rectangle).GetProperty("Height");
propertyInfo.SetValue(rectangle, 5, null);

The Height value (as reported by the debugger) never gets set to anything - it stays at the default value of 0.

I have done plenty of reflection on classes before and this has worked fine. Also, I know that when dealing with structs, you need to use FieldInfo.SetValueDirect if setting a field, but I don't know of an equivalent for PropertyInfo.

Answer

Jon Skeet picture Jon Skeet · Jun 8, 2011

The value of rectangle is being boxed - but then you're losing the boxed value, which is what's being modified. Try this:

Rectangle rectangle = new Rectangle();
PropertyInfo propertyInfo = typeof(Rectangle).GetProperty("Height");
object boxed = rectangle;
propertyInfo.SetValue(boxed, 5, null);
rectangle = (Rectangle) boxed;

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