c# - Html.ActionLink passes null value -

c# - Html.ActionLink passes null value -

i have view displays list of objects. there have action link

@html.actionlink("add", "add", new {str = model.first().directory})

and method in controller.

public actionresult add(string parentdirectory) { userservice.node file = new userservice.node() { parent_directory = parentdirectory, }; homecoming view(file); }

for reason unknown me parentdirectory null, when tried this

@html.actionlink("add", "add", new {str = "hello"})

how can prepare ?

since parameter name of add controller action method parentdirectory, need alter this

@html.actionlink("add", "add", new { str = model.first().directory })

to this

@html.actionlink("add", "add", new { parentdirectory = model.first().directory })

c# asp.net-mvc