I have to write an object in to binary file.My struct looks like this.
Struct Company
{
int numberofemployees
list of Struct Employee.
}
Struct Employee
{
string EmployeeName;
string Designation;
}
What is the best way to do the above operation? Regards Raju
In my understanding, BinaryFormatter is the tool for this job.
Edit: As Marc explains in the comments, BinaryFormatter has certain disadvantages. He recommends protobuf-net in his blog.
BinaryFormatter is generally a really bad choice for persistence....Here is an example how you can read/write a binary file:
using System;
using System.IO;
public class BinaryFileTest {
private static void Main() {
FileStream fs = new FileStream("test.dat", FileMode.Create);
BinaryWriter w = new BinaryWriter(fs);
w.Write(1.2M);
w.Write("string");
w.Write("string 2");
w.Write('!');
w.Flush();
w.Close();
fs.Close();
fs = new FileStream("test.dat", FileMode.Open);
StreamReader sr = new StreamReader(fs);
Console.WriteLine(sr.ReadToEnd());
fs.Position = 0;
BinaryReader br = new BinaryReader(fs);
Console.WriteLine(br.ReadDecimal());
Console.WriteLine(br.ReadString());
Console.WriteLine(br.ReadString());
Console.WriteLine(br.ReadChar());
fs.Close();
}
}
What exactly do you want the output to look like? You can write it manually (see Lirik's answer), or if you want runtime support, perhaps something like protobuf-net.
This would be trivial to do if you were using classes (which I expect you actually should be), but additionally protobuf-net v2 (only available as source at the moment) should work with that "as is".
For info, here is how I would do it as classes:
public class Company
{
private readonly List<Employee> employees = new List<Employee>();
public List<Employee> Employees { get { return employees;}}
}
public class Employee
{
public string EmployeeName {get;set;}
public string Designation {get;set;}
}
This could be decorated with serialization attributes, or (again, using protobuf-net v2) something like this test (which passes):
[Test]
public void CanSerializeCompany()
{
var model = TypeModel.Create();
model.Add(typeof(Company), false).Add("Employees");
model.Add(typeof(Employee), false).Add("EmployeeName", "Designation");
model.CompileInPlace();
Company comp = new Company {
Employees = {
new Employee { Designation = "Boss", EmployeeName = "Fred"},
new Employee { Designation = "Grunt", EmployeeName = "Jo"},
new Employee { Designation = "Scapegoat", EmployeeName = "Alex"}}
}, clone;
using(var ms = new MemoryStream()) {
model.Serialize(ms, comp);
ms.Position = 0;
Console.WriteLine("Bytes: " + ms.Length);
clone = (Company) model.Deserialize(ms, null, typeof(Company));
}
Assert.AreEqual(3, clone.Employees.Count);
Assert.AreEqual("Boss", clone.Employees[0].Designation);
Assert.AreEqual("Alex", clone.Employees[2].EmployeeName);
}
(and writes 46 bytes)
It should work with private fields, structs, etc - I'd have to take a look...
If you are able to add attributes, then you don't need to set up the model manually (the first 4 lines). The rest of the code is just showing full round-trip usage.
struct, and I expect this is going to bite you in interesting ways. I would use aclasshere...