Using gettype.getproperty on a usercontrol property

i got a usercontrol with public property. This user control is on a form. When i loop through all the control of this form I got a function that modify prperty of the control. It works weel except for my usercontrol.

What i want to do is :

 Dim pinstance As PropertyInfo = Tmp_Ctrl.GetType.GetProperty(item.prop)

tmp_ctrl contain a control of the form when i loop through all of them. when tmp_ctrl contain my usercontrol, propertyinfo is "set" to nothing. item.prop is a string that contain the name of the property

Thank you for any idea.