What does the keyword 'New' do in VBA?
excel, vba
Solution
When you Dim a variable you are specifying what data type it will hold. At the time of creation, its value is always `Nothing` until you initialize it. `Set T = Application.Workbook(Bk)` initializes the T variable to the specific instance of Application.Workbook, in this case 'Bk'.
When you `Dim fso as FileSystemObject`, you are basically saying that `fso` will hold, at some point, a `FileSystemObject`; however its initial value is `Nothing` until you initialize it using `Set fso = New FileSystemObject`. The `New` keyword implies you're creating a new object instead of initializing the variable with an existing object as you do with `Set T = Application.Workbook(Bk)`
Also note that `Set fso = FileSystemObject` would be invalid because it doesn't know what instance of `FileSystemObject` you wish to assign to it. This is why you use the `New` keyword to create a new instance of FileSystemObject.
As stated before, `Dim WS As Worksheet` merely tells the compiler that you want variable WS to hold a Worksheet object. Since nothing else is specified, at the point of Dim, WS is set to `Nothing`
`Dim myClassModule As New cl_ChartEvents` is equivalent to doing:
Dim myClassModule as cl_ChartEvents
Set myClassModule = New cl_ChartEvents
... except on one line of code instead of two. This differs from `Dim WS As Worksheet` in that the variable is initialized straight away, i.e. `myClassModule` is set to a new instance of `cl_ChartEvents` instead of `Nothing`.
Hope this helps!
Problem
In VBA procedures we are constantly meeting the keyword New usually on instantiation of an object reference to an existing object instance. But in some instantiations we use the keyword New while in others we don't for example: `Dim T As Excel.Workbook` `Set T = Application.Workbooks(Bk)` In the upper example No.1 the "New" keyword has not been used `Dim fso As FileSystemObject` `Set fso = New FileSystemObject` In the upper example No.2 the New keyword is being used Why that? Keep in mind i'm fresh of the boat in VBA but i will do my best to understand! In addition to that i also get confused when is used/not-used in declaring an object reference for example: `Dim WS As Worksheet` In the upper example No.1 the "New" keyword has not been used `Dim myClassModule As New cl_ChartEvents` In the upper example No.2 the New keyword is being used The Microsoft Help just tells me nothing... Keyword that enables implicit creation of an object. If you use New when declaring the object variable, a new instance of the object is created on first reference to it, so you don't have to use the Set statement to assign the object reference. Gratz2u Dear people just a last dust-off for deep understanding `Dim WS as Worksheet` `Set WS = Worksheets("Sheet1")` Right here we are creating an object that already existed in order to open MS Excel (lets say for examples sake in "default mode") of course which is Sheet1. Since it exists and the `New` keyword is out of the question how could we instantiate this object in one line right away? 4 @exantas Sorry says not enough rep to post pic :-(