C# 无法在'<&燃气轮机;f__AnonymousType1`2正在使用bindingSource3.AddNew();
当我使用以下代码时,会发生错误C# 无法在'<&燃气轮机;f__AnonymousType1`2正在使用bindingSource3.AddNew();,c#,linq,entity-framework,C#,Linq,Entity Framework,当我使用以下代码时,会发生错误 testtelContext db = new testtelContext(); var qry = (from p in db.firstlasts join i in db.firstnames on p.Idfname equals i.Idfname s
testtelContext db = new testtelContext();
var qry = (from p in db.firstlasts
join i in db.firstnames
on p.Idfname equals i.Idfname
select new
{
id = p.idfl,
name = i.fname
}).ToList();
bindingSource3.DataSource = qry;
dataGridView5.DataSource = bindingSource3;
bindingSource3.AddNew();
使用bindingSource3.AddNew()时出错
错误:无法对“f_uAnonymousType1
2[[System.Int32,mscorlib,Version=4.0.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089],[System.String,mscorlib,Version=4.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089]”类型调用AddNew。此类型没有公共默认构造函数。您可以在“f_uuAnonymousType1”
2[[System.Int32,mscorlib,Version=4.0.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089],[System.String,mscorlib,Version=4.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089]]'如果设置AllowNew=true并处理AddingNew事件,则键入。如果数据源是匿名类型对象的集合,则不能调用AddNew
因此,您必须声明自定义类:
public class BindingItem
{
public int id { get; set;}
public string name { get; set; }
}
并将查询更改为返回该对象的集合,而不是匿名对象:
var qry = (from p in db.firstlasts
join i in db.firstnames on p.Idfname equals i.Idfname
select new BindingItem
{
id = p.idfl,
name = i.fname
}).ToList();
匿名类是只读的,因此
AddNew
没有意义。