How to return string/int from dbcontext-CodePudding

I want to get role_code from db.roles based on role_id and return then role_code as the result.

I have tried this

public static string GetRoleCode (int role_id)
{
    string result = "";
    using (var db =new DbContext())
    {
        result = db.roles
            .Where(r => r.Id == role_id)
            .Select(r => new
            {

            }).FirstOrDefault();
    }
    return result;
}

What's missing from my code?

CodePudding user response：

Since your result is a string, you can't return with anonymous type in .Select().

You should just return the role code as:

.Select(r => r.Code) // Assume this field you need to return

result = db.roles
    .Where(r => r.Id == role_id)
    .Select(r => r.Code)
    .FirstOrDefault();

If you use C# 6 or above, you can use Null conditional operator as below:

result = db.roles
    .FirstOrDefault(r => r.Role_Id == role_id)?
    .Code;