C#

Type T; // type of a property of _target. The type itself is T[]
//, but here I have a type of elements of an array.
List<object> olist; // list where am I going to store array's elements.
IEnumerable<PropertyInfo> subProps; // properties of T

// GetO creates an instance of T and assigns all it's properties.
olist.AddRange(resultSet.Select(result => GetO(T, subProps, result)));
                                
// Here I got ArgumentException
// Object of type 'System.Object[]' cannot be converted to type 'GameEditor.Model.SceneExit[]'.
// In a debugger I can see that all elements of olist are of type T. It is understandable.
// But the list itsefs is still List<object> and therefore SetValue fails
prop.Info.SetValue(_target, olist.ToArray(), new object[0]); 

Type t = ...;
dynamic olist =
    typeof (List<object>).GetGenericTypeDefinition().MakeGenericType(new Type[] {t})
        .GetConstructor(new Type[] {typeof(int)}).Invoke(new object[] {resultSet.Count});
IEnumerable<PropertyInfo> subProps = ...;

foreach (SparqlResult result in resultSet)
    olist.Add(GetO(t, subProps, result)); // fails here this time (parameter doesnt match)
// Although GetO returns an object of correct type, but formally it's still an 'object'
// (dynamic thing is 'too good'...)
                                
prop.Info.SetValue(_target, olist.ToArray(), new object[0]);

private void sekmeyiKapatToolStripMenuItem_Click(object sender, EventArgs e)
       {
           foreach (DetayForm item in this.MdiChildren)
           {
               if (item.tbpg.Equals(tabControl1.SelectedTab))
               {
                   item.Select();
                   item.Close();
                   item.tbpg.Dispose();
               }
           }
       }