Select All distinct values in a column using LINQ

Question

I created a Web Api in VS 2012. I am trying to get all the value from one column "Category", that is all the unique value, I don't want the list to be returned with duplicates.

I used this code to get products in a particular category. How do I get a full list of categories (All the unique values in the Category Column)?

public IEnumerable<Product> GetProductsByCategory(string category)
    {
        return repository.GetAllProducts().Where(
            p => string.Equals(p.Category, category, StringComparison.OrdinalIgnoreCase));
    }

Answer 1

To have unique Categories:

var uniqueCategories = repository.GetAllProducts()
                                 .Select(p => p.Category)
                                 .Distinct();

Answer 2

var uniq = allvalues.GroupBy(x => x.Id).Select(y=>y.First()).Distinct();

Easy and simple

Answer 3

I have to find distinct rows with the following details class : Scountry
columns: countryID, countryName,isactive
There is no primary key in this. I have succeeded with the followin queries

public DbSet<SCountry> country { get; set; }
    public List<SCountry> DoDistinct()
    {
        var query = (from m in country group m by new { m.CountryID, m.CountryName, m.isactive } into mygroup select mygroup.FirstOrDefault()).Distinct();
        var Countries = query.ToList().Select(m => new SCountry { CountryID = m.CountryID, CountryName = m.CountryName, isactive = m.isactive }).ToList();
        return Countries;
    }