“Only arguments that can be evaluated on the client are supported for the String.Contains method”

Question

public static void MyFunction(MyErrorClass err)
{
    var query = from filter in DataContext.ErrorFilters select filter;
    query = query.Where(f => err.ErrorMes         


        

Answer 1

Hmm... It seems the Linq2SQL IndexOf translation is smarter than for Contains. This should work:

public static void MyFunction(MyErrorClass err)
{
    var query = DataContext.ErrorFilters;
    query = query.Where(f => err.ErrorMessage.IndexOf(f.ErrorMessage)>=0);
    List filters = query.ToList();
    //...more code
}

In LinqPad it can be seen this uses CHARINDEX, because we've asked for more than just "contains", rather "where is it", but it is happy to work with server-side expressions.