'"An expression tree may not contain a call or invocation that uses optional arguments" in LINQ expression with split string entity?

var list1 = _context.Employees.Where(x=> x.EmployeeId.Equals(empId)
                    && **x.deptIds.Split(",")**.ToList().Any(p => (p!=(deptId.ToString()))));

Where, x.deptIds is department ids stored as string separated by comma. Getting erro "An expression tree may not contain a call or invocation that uses optional arguments". How to solve it?

c++sharpentity-frameworklinq.net-corewebapi


Solution 1:[1]

Just specify an optional parameter. string.Split(",") becomes string.Split(",", System.StringSplitOptions.None)

providing optional parameters to string.Split resolved my error

Solution 2:[2]

As the comments pointed out, storing multiple values in a field is a very bad design choice, so noone should ever get to the point when they have to use String.Split in a Linq.

But to answer your question, you can use String.Contains, String.StarsWith and String.EndsWith, these can be translated to SQL. For example you can write:

var list1 = _context.Employees.Where(x=> x.EmployeeId.Equals(empId)
    && (x.deptIds.Contains("," + deptId.ToString() + ",") 
        || x.deptIds.StartsWith(deptId.ToString() + ",") 
        || x.deptIds.EndsWith("," + deptId.ToString()
    ));

This solution can change depending on where you have spaces around the commas in the database.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 snehakatke
Solution 2 Annosz

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