VB.NET - How do I use pointers to pointers (if even possible)

[Ophir]

Hi

I want to use the New function for an object with array of objects as parameters something like this - 

Sub New(varPar () as Object)

End Sub

In my Class I have several objects that can be initialized.

I'm trying to make a the code general so the calling code will put in the varPar array the objects it wants to init and I will use something like this - 

Dim obj1 as <type1>

Dim obj2 as <type2>

.

.

.

dim objN as <typeN>

 

Sub New(varPar () as Object)

 if  varPar is nothing then

      return

end if       

if varPar.Length > 0 then

      obj1 = varPar(0)

if varPar.Length > 1 then

      obj1 = varPar(1)

 etc...      

End Sub

 

I want to do that in a loop like this

Dim obj1 as <type1>

Dim obj2 as <type2>

.

.

.

dim objN as <typeN>

dim varArray() as object = { obj1,obj2,obj3.......objN}

 

Sub New(varPar () as Object)

 if  varPar is nothing then

      return

end if       

for i = 0 to varPar.Lentgh -1 

      varArray(i) = varPar(i)

next

End Sub

 

This will init the varArray but not obj1 obj2 obj3 etc.

Does anyone know how I can achieve this?

It is trivial in C, but in VB I don't know if it is possible or not.

Thanks

[+Raphaël G. MVC]

  On 05/07/2018 at 11:29, Ophir said:

Hi

I want to use the New function for an object with array of objects as parameters something like this - 

 

<snipped>

 

This will init the varArray but not obj1 obj2 obj3 etc.

Does anyone know how I can achieve this?

It is trivial in C, but in VB I don't know if it is possible or not.

Thanks

Expand  

I'm not sure I fully understand the question. So here are some questions of my own

 

The array injected in the constructor always has the same amount of elements as the internal array?

Are you trying to make each element of the internal array point to the corresponding element of the array injected in the constructor?

 

Could you maybe tell us which problem this construction is trying to solve? There might be a more efficient way of doing that in VB.NET.

[Ophir]

  On 05/07/2018 at 12:10, Raphaël G. said:

I'm not sure I fully understand the question. So here are some questions of my own

 

The array injected in the constructor always has the same amount of elements as the internal array?

Are you trying to make each element of the internal array point to the corresponding element of the array injected in the constructor?

 

Could you maybe tell us which problem this construction is trying to solve? There might be a more efficient way of doing that in VB.NET.

Expand  

The Array injected does not have to have the same amount of elements as the internal one.

I want to initialize the class variables obj1 obj2 obj3 etc in a loop instead of one by one while checking the Injected Array length.

 

In C I will put the Address of obj1 obj2 obj3 etc in the Internal Array and do something like this

 

void *varArray[] = { &obj1, &obj2, &obj3......&objN}

 

for(i = 0; i < <Injected Array>.length; i++)

{

        *varArray=varPar;    //By that I actually Initializing obj1, obj2, obj3 etc

}

 

I hope it is clearer now.

 

Do not know why when I submit the square parenthesis are removed.

Edited July 5, 2018 by Ophir

[Farchord]

  On 05/07/2018 at 14:35, Ophir said:

The Array injected does not have to have the same amount of elements as the internal one.

I want to initialize the class variables obj1 obj2 obj3 etc in a loop instead of one by one while checking the Injected Array length.

 

In C I will put the Address of obj1 obj2 obj3 etc in the Internal Array and do something like this

 

void *varArray[] = { &obj1, &obj2, &obj3......&objN}

 

for(i = 0; i < <Injected Array>.length; i++)

{

        *varArray=varPar;    //By that I actually Initializing obj1, obj2, obj3 etc

}

 

I hope it is clearer now.

 

Do not know why when I submit the square parenthesis are removed.

Expand  

If I'd convert what you posted here into vb.net, :

 

 

Dim list() As String = {"something", "something2"}

            For Each item In list

                'Then simply call the item

            Next

 

If you want to track each item, I usually make my own classes, for example let's say a standard name/value keypair:

 

Public class NameValueKeyPair

        public name as string

        public value as string

end class

 

Then, in a sub/function:

 

dim NameValueKeyPairList as new list(of NameValueKeyPair)

Dim NameValueKeyPair as new NameValueKeyPair

NameValueKeyPair.name = "name"

NameValueKeyPair.value = "value"

Namevaluekeypairlist.add(namevaluekeypair)

 

Do that in a loop, and then you can loop through the list to find what you need, for example:

 

For each item in NameValueKeyPairList

      If item.name = "name" then

             'Found it!

      End if

Next