LINQ To SQL Contains Case Sensitive Searching

Question

When I use below query, it gets result perfectly. But it is case-sensitive. Here is my codes:

    IQueryable<article> results;
    if (rrbAuthor.IsChecked)
        results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid where a.author.Contains(textBox1.Text) select a).Distinct();
    else if (rrbKeywords.IsChecked)
        results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid where k.word.Contains(textBox1.Text) select a).Distinct();
    else
        results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid where a.title.Contains(textBox1.Text) select a).Distinct();

    ListArticles(results, 1);

How can I manage to get results in in-sensitive case?

Answer 1

You can transform string into lower case, using ToLower() method and then do comparison
You can also use null propagation in oder to avoid NullReference Exception in case some of the stirngs is null.

Try following

  IQueryable<article> results;
  if (rrbAuthor.IsChecked)
    results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid
               where a.author?.ToLower().Contains(textBox1.Text?.ToLower()) == true
               select a).Distinct();
  else if (rrbKeywords.IsChecked)
    results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid
               where k.word?.ToLower().Contains(textBox1.Text?.ToLower()) == true
               select a).Distinct();
  else
    results = (from a in _db.articles join k in _db.keywords on a.id equals k.aid
               where a.title?.ToLower().Contains(textBox1.Text?.ToLower()) == true
               select a).Distinct();
  ListArticles(results, 1);