How can I do case insensitive string search with Linq and SQL Server?

问题

Here is my current code for searching tags:

    public JsonResult TagSearch(string term) {
        if (term == null || term == "")
            return Json("");

        var tags = (from t in _session.All<Tag>() where t.Name.Contains(term) select t.Name).Take(6).ToArray();

        return Json(tags);
    }

How could I do case insensitive string search instead?

回答1:

The Contains() method is converted to case-insensitive operation in SQL. I think the code I posted is case insensitive.

回答2:

Is changing the collation of the column out of the question?

回答3:

Use the ToLower method. Like this:

var tags = (from t in _session.All<Tag>() where t.Name.ToLower().Contains(term.ToLower()) select t.Name).Take(6).ToArray();

来源：https://stackoverflow.com/questions/3314130/how-can-i-do-case-insensitive-string-search-with-linq-and-sql-server