c# - Namespace '<global namespace>' contains a definition conflicting with alias 'PersianDate' -

i'm developing winform application in c# , fine. of sudden weird error when tried run application.

namespace '' contains definition conflicting alias 'persiandate'

this line throws error.

private persiandate _quotationdate; 

all done before getting error add form_load event.

private void frmadddragsource_load(object sender, eventargs e)  {    this.text = "source";  } 

does knows why happens , how can fix it?

update usings:

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.data.sqlserverce; using system.drawing; using system.linq; using system.text; using system.windows.forms; using fishtablighpro.utility; using persiandate = freecontrols.persiandate; 

since defined persiandate alias freecontrols.persiandate namespace. compiler can't tell whether persiandate refer namespace alias created, or persiandate type defined in it.

try point directly persiandate type:

private persiandate.persiandate _quotationdate;