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

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

您可以在LINQ-to-Objects中执行string.Format ：

 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(); 

Answer 2

试试这个

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