无法将类型'System.Linq.IQueryable'隐式转换为'string' [英] Cannot implicitly convert type 'System.Linq.IQueryable' to 'string'

问题描述

我从DB获取员工姓名并将其显示在标签中，如果名称存在，则必须显示姓名，如果没有，则表示没有记录。



var hdd =来自db.EMP中的d

其中d.Name ==JOHN

选择d.City;



Label1.Text = hdd;



但我收到错误无法隐式转换类型'System.Linq.IQueryable< char> 'to'string'

解决方案

您可能想要阅读错误消息。它确切地告诉你什么是错的。你试图将一个不是字符串的对象分配给需要字符串的属性（Text）。



你的代码没有任何意义，因为LINQ查询返回一个IQueryable对象（可以返回0或更多结果），你实际上无法将其转换为字符串。

如果你不使用'Single：这会容易得多：

  var  hdd =（ from  d  in  db.EMPs 
 其中​​ d.Name ==  < span class =code-string> JOHN 
  select  d）.ToList（）; 
 
 Label1.Text =（hdd.Count ==  0 ）？  不匹配：hdd [ 0  ]。市; 

I am fetching the employee name from DB and displaying it in a label,if the name exists it has to show the name if not it has tell that no record exists.

var hdd = from d in db.EMPs
where d.Name == "JOHN"
select d.City;

Label1.Text = hdd;

But i am getting an error Cannot implicitly convert type 'System.Linq.IQueryable<char>' to 'string'

解决方案

You might want to read the error message. It's telling you EXACTLY what's wrong. You're trying to assign an object that is not a string to a property (Text) that requires a string.

Your code doesn't make any sense since the LINQ query returns an IQueryable object (0 or more results can be returned) and you really can't convert that to a string.

This is much easier if you do not use 'Single:

var hdd = (from d in db.EMPs
             where d.Name == "JOHN"
               select d).ToList();

Label1.Text = (hdd.Count == 0) ? "No match" : hdd[0].City;

这篇关于无法将类型'System.Linq.IQueryable'隐式转换为'string'的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！