LINQ to Entities无法识别方法'System.String Format

Question

我怎样才能重构这个LINQ以使其工作？

var a =  (from app in mamDB.Apps where app.IsDeleted == false 
                select string.Format("{0}{1}",app.AppName, 
                app.AppsData.IsExperimental? " (exp)": string.Empty))
               .ToArray();}

我现在得到错误:

LINQ to Entities无法识别方法'System.String Format(System.String,System.Object,System.Object)'方法,并且此方法无法转换为商店表达式.

我无用地尝试过:

return (from app in mamDB.Apps where app.IsDeleted == false 
        select new string(app.AppName + (app.AppsData != null && 
        app.AppsData.IsExperimental)? " (exp)": string.Empty)).ToArray();

Answer 1

你可以string.Format在LINQ-to-Objects中做后面的事情:

var a =  (from app in mamDB.Apps where app.IsDeleted == false 
         select new {app.AppName, app.AppsData.IsExperimental})
         .AsEnumerable()
         .Select(row => string.Format("{0}{1}",
            row.AppName, row.IsExperimental ? " (exp)" : "")).ToArray();