Get or set value for a field with reflection

gistfile1.cs

class RTest
{
	public static int staticInt;
	public int instantInt;
}

Type type = typeof(RTest);
var field = type.GetField("staticInt");
field.SetValue(null, 10);
Console.WirteLine(field.GetValue(null));//why use null here? because this is a static field

var obj = new RTest();
var field2 = type.GetField("instantInt");
field2.SetValue(obj, 11);
Console.WirteLine(field.GetValue(obj));//pay attention to the parameter.