Using Context Factory

Context Factory.cs

public interface IContextFactory
{
   SampleContext GetContext();
}

public class ContextFactory
    :IContextFactory,IDisposable
{
    private SampleContext _sampleContext;

    public SampleContext GetContext()
    {
        return _sampleContext ?? (_sampleContext = new SampleContext());
    }

    public void Dispose()
    {
        if (null != _sampleContext)
            _sampleContext.Dispose();
    }
}

public class SampleContext
    :DbContext
{
    public DbSet<Category> Category { get; set; }

    public SampleContext(string contextName)
        :base(contextName)
    {
    }

    public SampleContext()
        :base("")
    {
    }

    public void Commit() 
    {
        base.SaveChanges();
    }
}