在 LINQ Where 子句不起作用中使用 String.Split

Question

I have below LINQ query:

List<string> paths = (from an in modelDb.MyTable
                            where an.Id == 0 &&
                                  an.fileName.Split('_')[0] == "19292929383833abe838ac393" &&
                                  an.fileName.Split('_')[1].ToUpper() == "FINANCE" &&
                                  an.fileName.ToUpper().Contains("SIGNED")
                            select an.filePath).ToList();

... which is throwing below error on run-time:

Entity Framework 'ArrayIndex' is not supported in LINQ to Entities

fileName field in the LINQ query is a column in MyTable of string data type and contains strings like:

8845abd344ejk3444_FINANCE_SIGNED.pdf
4565abd34ryjk3454_FINANCE_UNSIGNED.pdf
477474jkedf34dfe4_MARKETING_UNSIGNED.pdf

and so on...

Answer 1

As stays in the message split will be not supported in the linq to sql and if you want to get result without additional methods, using Contains() should give you required result

List<string> paths = (from an in modelDb.MyTable
        where an.Id == 0 &&
                an.fileName.Contains("19292929383833abe838ac393") &&
                an.fileName.Contains("FINANCE") &&
                an.fileName.ToUpper().Contains("SIGNED")
        select an.filePath).ToList();

Another way is to load all in memory and do split after that, eg

List<string> temp = (from an in modelDb.MyTable
                            where an.Id == 0  
                                  an.fileName.ToUpper().Contains("SIGNED")
                            select an.filePath).ToList();

paths = temp.Where(an =>
     an.fileName.Split('_')[0] == "19292929383833abe838ac393" &&
     an.fileName.Split('_')[1].ToUpper() == "FINANCE").ToList();