Create a csv file from a list of objects C#

Question

How can I create a csv file from a generic list of objects? In the example, a list of molecules, containing 3 objects of the type Molecule:

namespace example_reactioncalc
{
 class Program
 {
 public class Molecule
 {
 public double property_A { get; set; }
 public double property_B { get; set; }
 }
 public static Molecule Reaction(Molecule molecule_1, Molecule molecule_2)
 {
 Molecule reacted_molecule = new Molecule();
 reacted_molecule.property_A = molecule_1.property_A + molecule_2.property_A;
 reacted_molecule.property_B = (molecule_1.property_B + molecule_2.property_B) / 2;
 return reacted_molecule;
 }
 static void Main(string[] args)
 {
 // Initiation of the list of molecules
 List<Molecule> molecules = new List<Molecule>();
 // Adding two molecules to the list
 molecules.Add(new Molecule() { property_A = 10, property_B = 20 });
 molecules.Add(new Molecule() { property_A = 3, property_B = 7 });
 // Reacting two molecules to get a new one: 
 Molecule new_molecule=Reaction(molecules[0],molecules[1]);
 molecules.Add(new_molecule);

Here, one can print the content of one of the properties of the list for the 3 objects:

 Console.WriteLine("Properties A and B of the 1st molecule:");
 Console.WriteLine(molecules[0].property_A);
 Console.WriteLine(molecules[0].property_B);
 Console.WriteLine("Property A and B of the 2nd molecule:");
 Console.WriteLine(molecules[1].property_A);
 Console.WriteLine(molecules[1].property_B);
 Console.WriteLine("Property A and B of the 3rd, new molecule:");
 Console.WriteLine(molecules[2].property_A);
 Console.WriteLine(molecules[2].property_B);
 Console.ReadLine();
 }
 }
}

The output:

Properties A and B of the 1st molecule:
10
20
Properties A and B of the 2nd molecule:
3
7
Properties A and B of the 3rd, new molecule:
13
13.5

So I need a csv file with the complete output:

10,20
3,7
13,13.5

I tried to find such method in the forums, but I only found examples for generic lists of arrays, and I was not able to make them work. I really appreciate any help on this issue (I'm a beginner in C#).

• Gustavo Oliveira: stackoverflow.com/questions/1890093/…
• Antonio Intini: @GustavoOliveira this example refers to a list of strings. In my case the list contain objects, which have themselves two different properties each. The csv should contain these properties listed per molecule.
• Jim G.: Does this answer your question? Fastest way to convert a list of objects to csv with each object values in a new line

Answer 1

CSV files are pretty straight forward to generate:

using (StreamWriter writer = new StreamWriter("myfile.csv"))
{
 foreach (Molecule molecule in molecules)
 {
 writer.WriteLine($"{molecule.property_A},{molecule.property_B}");
 }
}

• Antonio Intini: Thanks for your reply! I'm getting an error: "The type or namespace 'StreamWriter' could not be found (are you missing a using directive or an assembly reference?)". Any guess of what should I do next?
• Antonio Intini: I found a correction for this: using (System.IO.StreamWriter writer = new System.IO.StreamWriter(@"myfile.csv")) Now it is working perfectly. Thank you so much!
• GBM: @itsme86 Your answer works perfectly! Do you know if there's a way to include the Headers from a list into the .csv file as well please?
• itsme86: @GBM Yes. All you need to do is write the header line as a comma-separated list before your loop. So just before the foreach line above, you can add writer.WriteLine("Property A,Property B");.

Answer 2

Have you tried System.IO.File yet? It's a simple way of opening and writing to a file: example.

It looks like you'll need some sort of method like the following;

 WriteMoleculesToFile(string pathToFile, List<Molecule> molecules) {
 using (System.IO.StreamWriter file = new System.IO.StreamWriter(@pathToFile)) {
 foreach (Molecule molecule in molecules) {
 file.WriteLine(String.Format("{0},{1}",molecule.property_A, molecule.property_B));
 }
 }
 }

• Antonio Intini: I was not able to run it. Molecule is not an array. I get the error: "Argument 2: cannot convert from 'System.Collections.Generic.List<example_reactioncalc.Program.Molecule>' to 'example_reactioncalc.Program.Molecule[]'
• BaconSodas: Here, try the edit instead. Should accept a List instead of an Array now