I have a class which has a internal method and i want to mock the internal method . But i am unable to mock it i.e. it is not calling the mocked function but calling the ori
Not with Moq.
But you can use the free Moles framework from MS to do such things. I wrote about it here: Mocking the Unmockable: Using Microsoft Moles with Gallio. (it applies not only to Gallio, but it gives a good overall impression of what you can do with Moles...). The other alternative would be Typemock...
HTH. Thomas