C# - Convert Object to Array to get Data by Index

Question

I have a webservice that returns me an object with data

 object data = _wsUsuario.CarregarDadosUsuario(_view.Usuario);

This object, called data, returns me the following:
[0] 84
[1] Marcelo Camargo
[2] [email protected]
[3] 2

If I try to do

MessageBox.Show(data[0]);

Then the compiler says me:

Cannot apply indexing to an expression of type 'object'. I searched and wonder if there is a way to convert this object of strings and integers to an array. Can you give me a hand?

If the underlying object is what you say it is, a simple cast should work MessageBox.Show(((string[])data)[0]); — Kevin DiTraglia
– Kevin DiTraglia, Commented Jul 17, 2014 at 19:10
What is CarregarDadosUsuario actually typed return - that is, what is the method signature? (I would hope it was an Array/IEnumerable/custom of some sort.) If it isn't object, you might be doing this The Hard Way by slopping it into such a variable. If it is unfortunately typed to return an object, what is the type of the actual object that is returned? — user2864740
– user2864740, Commented Jul 17, 2014 at 19:10

ProgrammingLlama · Accepted Answer · 2014-07-17 19:20:38Z

2

Assuming the data is an array of strings, then you would need to cast it accordingly:

object[] oData = (data as object[]) ?? new object[0];

This will TRY to cast to object[] but if it isn't castable, it will return null and the null coalescing operator ?? will return an empty object array instead.

edited Jul 17, 2014 at 19:20

answered Jul 17, 2014 at 19:08

ProgrammingLlama

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4 Comments

Marcelo Camargo Over a year ago

I have both strings and integers.

ProgrammingLlama Over a year ago

Have updated my answer. You will have to cast the strings and integers in the array accordingly, of course.

leppie Over a year ago

And it will crash when indexing. Why not just not leave the result null and check for it? Edit: ToString would be semi-sufficient.

ProgrammingLlama Over a year ago

@leppie Could do, I suppose :) Either way he'll have to check for something

Amir Popovich · Accepted Answer · 2014-07-17 19:17:48Z

1

An object doesn't have an indexer. An array does.

I think you downcasted the functions return type from a specific strong type object(some kind of array) into a basic 'object'.

What should happen:

// res should be an array
CarregarDadosUsuarioReturnType res = _wsUsuario.CarregarDadosUsuario(_view.Usuario);
MessageBox.Show(res[0]);

If, for any reason this service implicitly recieves an object simply cast this into:

object data = _wsUsuario.CarregarDadosUsuario(_view.Usuario);
var arr = data as ArrType[]; // where ArrType = the array type.
MessageBox.Show(arr[0]);

edited Jul 17, 2014 at 19:17

answered Jul 17, 2014 at 19:09

Amir Popovich

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