C# equivilent to a VB property with parameters.

[BlackStone]

What is the C# equivilent to a VB property such as this one??

 

Public Property Numbers(ByVal Index As Integer) As Integer
   ....
End Property

[Joe Mamma]

What is the C# equivilent to a VB property such as this one??

 

Public Property Numbers(ByVal Index As Integer) As Integer
....
End Property

public class IntClass
{
 int [] _ints = new int[3] {1,2,3};
 public int this[int index]
 {
get
{ 
  return _ints[index];
}
set
{ 
  _ints[index] = value;
}
 }
}

 

 

IntClass ints = new IntClass();

 

int x = ints[1];

// x = 2

ints[1] =100;

int x = ints[1];

// x = 100

[BlackStone]

The above is like a default property in VB. (Indexers in C#)

 

But what do you do if you want to have many properties that act like arrays?

Like this(just an example):

(vb)

Public Class Buffer

   Private mBytes() As Byte

   Public Property Bytes(ByVal Index As Integer) As Byte
       Get
           Return mBytes(Index)
       End Get
       Set(ByVal value As Byte)
           mBytes(Index) = value
       End Set
   End Property

   Public Property Chars(ByVal Index As Integer) As Char
       Get
           Return Chr(mBytes(Index))
       End Get
       Set(ByVal value As Char)
           mBytes(Index) = Asc(value)
       End Set
   End Property

End Class

Is the only way to do this to use seperate procedures for set/get??

[Arch4ngel]

I think it's something C# can't do. Correct me if I'm wrong.

[cyclonebri]

I think it's something C# can't do. Correct me if I'm wrong.

 

I am not sure if I'm missing the question, but I think that anytime you want to set or get properties across a class you should use a property with get/set functionality.

 

You could write a public function that would allow you to get or set though without having to use the property syntax...

 

For instance, in your class you could have the following:

[CS]

private byte[] m_Bytes = new byte[10];

 

//this public property gives you the ability to

//get/set the entire array

//from outside of the class:

public byte[] Bytes

{

get

{

return m_Bytes;

}

set

{

m_Bytes = value;

}

}

 

//This public function allows you to retrieve a specific

//char from within the array

public char GetChar(int index)

{

return Convert.ToChar(m_Bytes[index]);

}

 

//This public function allows you to set a specific

//char into the array from outside the class

public void SetChar(int index, string newvalue)

{

m_Bytes[index] = Convert.ToByte(newvalue);

}

[/CS]

 

I hope that helps with your question...

[Nerseus]

I don't think there's a way to do properties with params in C# directly. You would have to do a combination of JoeMamma's and cyclonebri solutions to get what you want.

 

Joe showed how to use an indexer to expose a property like an array. cyclone showed how to expose a private member as a property. If you create a new class that has an indexer and expose your private member variable of that new class type, you'd end up with something like:

classA.PropA["hi"] = 123;

 

In this case, PropA is a property in ClassA (classA being the instance). It would likely expose a private member variable such as propA that was of type NewClass. NewClass would expose the indexer as a string ("hi") and return an int value. If you need a sample, let me know. Not that I'd write one up, but I'd think about it :)

 

-ner

[mocella]

You can only have one indexed property per class (the "this", which is your indexer). I went through this headache early in the planning stages of my current project, but managed to design compeletly around them for most situations.

 

Here's a pretty decent article I had bookmarked from my earlier searches:

http://www.csharphelp.com/archives/archive140.html

[Joe Mamma]

You can only have one indexed property per class (the "this"' date=' which is your indexer). I went through this headache early in the planning stages of my current project, but managed to design compeletly around them for most situations.[/quote']

actually, it is limited by the index type.

 

this means you can have various enums and indexers specific to enumerations which can be quite useful and descriptive -

 

public class IntsAndStrings
{
 public enum EnumInts 
 {
  a = 1 , b = 2 , c = 3
 }
 public enum EnumStrings
 {
  a = 1 , b = 2 , c = 3
 }

 int [] _ints = new int[3] {1,2,3};
 string [] _strings = new string[3];
 
 public int this[EnumInts index]
 {
  get
  { 
return _ints[(int)index];
  }
  set
  { 
_ints[(int)index] = value;
  }
 }
 public string this[EnumStrings index]
 {
  get
  { 
return _strings[(int)index];
  }
  set
  { 
_strings[(int)index] = value;
  }
 }

}

 

   IntsAndStrings ist = new IntsAndStrings();
  int x = ist[intsAndStrings.EnumInts.a];
  ist[intsAndStrings.EnumInts.a] = 1000;
  string s = ist[intsAndStrings.EnumStrings.a];
  ist[intsAndStrings.EnumStrings.b] = "Byte Me!!!";

[BlackStone]

I made a dll to see what would happen if I had a vb class with properties + params. Apparently behind the seens seperater procedures are made for each, so in C#, it had get_bytes,set_bytes, etc..

Oh, well I guess Ill go with the sloppier Get/Set procedures. All the solutions above are very interesting, but they are too complex for the simple needs of a property+params.

[VBAHole22]

bloody C#!!!