not able to assign value to ListView Object

I am working on xamarin form based ios app. I am using a keyword driven framework in which I am passing Alias Name, Keyword (Action to be performed) and test data from excel sheet. 

when I directly assign value to Alias name of the object in my script, it workes fine --

Aliases.Device.processQaA36020.ManageContactPopup.Frame.StackLayout.Grid.lvAccounts.TemplatedItems.Item(0).BindingContext.Role = "Test Role"   //It works fine and the value 'Test Role' is set in Role field

 

But when I pass the value through variable it does not work. e.g.

 

function InputListObj(TestObj,InData)  //Testobj  is Alias name of Object on screen  and InData has the string that needs to be set in the field.
{
var obj = eval(TestObj)

Obj = InData
Delay(1000)

}

 

Can anyone please let me how to get it work.