Question

I’m having an issue toLower() in lambda query. I have this code

var filterResult = articleList
                        .Where(m => m.Summary
                            .Contains(filteredModel.Keyword) || m.Body.Contains(filteredModel.Keyword) || m.Headline.Contains(filteredModel.Keyword) 
                            || m.Title.Contains(filteredModel.Keyword))
                        .AsQueryable();

I need to add toLower() method as sql. For example:

var filterResult = articleList
    .Where(m => m.Summary.toLower()
        .Contains(filteredModel.Keyword.toLower()) || m.Body.toLower().Contains(filteredModel.Keyword.toLower()) || m.Headline.toLower().Contains(filteredModel.Keyword.toLower()) 
        || m.Title.toLower().Contains(filteredModel.Keyword.toLower()))
    .AsQueryable();

As above code, lambda doesn’t allow to use. I wonder if there is other way to do to achieve this.

Answer 1

ToLower should work, try breaking it up into different lines to narrow down which check is failing – remember it won’t execute until you actually pull the results down e.g.

var keyword = filteredModel.Keyword.ToLower();
var filterResult = articleList.Where(m => m.Summary.ToLowerInvariant().Contains(keyword));
filterResult = filterResult.Where(m => m.Body.ToLower().Contains(keyword));
filterResult = filterResult.Where(m => m.Headline.ToLower().Contains(keyword));
filterResult = filterResult.Where(m => m.Title.ToLower().Contains(keyword));

Also just an FYI – if your converting to lower case for culture-independant comparison then you should be using ToLowerInvariant…or better yet using ToUpperInvariant as it’s more reliable.