Is it possible to do dynamic property referencing in C#?

[jonnyc23]

If so how?

Say you have a class like:

public class MyClass
{
  public double[] DataSet1;
  public double[] DataSet2;
}
 

and i have a string called MyString that is "DataSet2".

Is it possible to somehow reference MyClass.DataSet2 dynamically by doing something like:

double[] MyOutput = MyClass.[MyString];


Thanks,
Jon

[Plater]

Other then using a Dictionary or System.Reflection I'm not sure you can.

[jonnyc23]

Should i be using some kind of string indexer instead?

[Plater]

Look at the NameValueCollection object, it should allow you supply a string for a name and store it with an object (any type of object)

[r035198x]

Look at the NameValueCollection object, it should allow you supply a string for a name and store it with an object (any type of object)

I don't know how you guys are communicating here but I don't even understand the first post. Is MyString a variable in MyClass which is static?

[balabaster]

I don't know how you guys are communicating here but I don't even understand the first post. Is MyString a variable in MyClass which is static?

We operate entirely telepathically ;)

The easiest way I can see of doing this is by using the Properties collection. Create a reference to the properties collection and add your properties into that. This way you can reference:

Msgbox(CType(Me.Properties("MyPropertyName"), Double)

Which I think in C# would be something like:

PropertyCollection MyProperties = new PropertyCollection();
private void Form1_Load(object sender, EventArgs e){
    MyProperties.Add("MyProperty1", null);
    MyProperties.Add("MyProperty2", null);
    MyProperties["MyProperty1"] = "Hello World";
    MessageBox.Show((string)MyProperties["MyProperty1"]);
}

I'm not sure if this is achievable at design-time though...the properties aren't normally added to a properties collection unless you specify that in the constructor of your class. This adds to code maintenance - if you add a property to your class, you have to remember to add it to the properties collection which should be read only so that other classes can't change it...so basically instead of just adding properties into your class in one place, you now need to remember to add them in two places...so yeah. There are lots of ways to achieve this - but I think this is likely the easiest...and if you look at the constructor of a form once you're done designing it, you'll see that it's the same kind of method used by microsoft with your controls collection using the IContainer. The plumbing is hidden away in the Form class that you inherit from, but it exposes a Controls collection that gives you the list of controls.
I think you could equally use the IContainer instead of the PropertyCollection - the effect is the same.

[r035198x]

It would be nice if the OP were to describe what they want to achieve.
I smell a simple design problem here.

[JamieHowarth0]

Hi guys,

I was just Googling around for a similar topic, not sure if anyone is still subscribed to this thread but I thought I'd just post this little gem I just found by searching for "dynamic properties class C#".
I will be making extensive use of this code in a desktop application I'm currently building which needs a base class and methods for serialising various objects and their properties into XML documents to be submitted to a web service so thought I'd share my tuppence (plus I'm then subscribed to this thread so I don't lose the link!).

codegecko

[Frinavale]

You know, I think that the original question isn't about creating dynamic properties, but more along the lines of how to access the properties dynamically. It seems pretty straight forward that reflection is the key here.

For example (imports/using the System.Reflection namespace)

  Dim myString As String = "DataSet2"
  Dim result() As Double = Nothing
 
  Dim mc As New MyClass 
  Dim mcProperties() As PropertyInfo = GetType(MyClass).GetProperties
 
  Dim dataSet2Property As PropertyInfo = Array.Find(mcProperties, Function(x As PropertyInfo) String.Compare(x.Name, myString, True) = 0)  
 
  If dataSet2Property IsNot Nothing
   result = dataSet2Property.GetValue(mc, BindingFlags.GetField, Nothing, Nothing, Nothing)
  End If
 

-Frinny

[Plater]

@codegecko
That was a very complex way of just using a Dictionary. WAY more work then you needed to do. And doesn't address the original issue.


And Frinny, you would post VBNET for a C# answer, lol

C#:(with less work :-P)

string myString="DataSet2";
double result=null;
 
MyClass mc= new MyClass();
System.Reflection.PropertyInfo dataSet2Property =MyClass.GetType().GetProperty(myString);
if (dataSet2Property != null)
{
    result = dataSet2Property.GetValue(mc, System.Reflection.BindingFlags.GetField, null, null, null);
}