//_AddressBookAdapter = new T_AddressBookTableAdapter(); //创建连接对象.
//var member = _AddressBookAdapter.GetMemberByName(txtName.Text.Trim());
_LinqToAddressBook = new LinqToUserDataContext();
var member = from m in _LinqToAddressBook.T_AddressBooks
where m.FName == txtName.Text.Trim()
select m;这两个代码,分别是用 xsd强数据类型和linq,查询的结果.
其中第一个(用强数据类型)查的时候报错:
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.我google一下,发现有人这样说:
This problem is usually caused by either null values being returned for columns not set to AllowDBNull, or duplicate rows being returned with the same primary key.我想说的是,我的数据库中字段 FName确实设置不能为空.但是我奇怪的是,我的数据库中,命名有那个数据,用强数据类型却返回空.何解? 用 Linq的话,是没有问题(可以获取).
//var member = _AddressBookAdapter.GetMemberByName(txtName.Text.Trim());
_LinqToAddressBook = new LinqToUserDataContext();
var member = from m in _LinqToAddressBook.T_AddressBooks
where m.FName == txtName.Text.Trim()
select m;这两个代码,分别是用 xsd强数据类型和linq,查询的结果.
其中第一个(用强数据类型)查的时候报错:
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.我google一下,发现有人这样说:
This problem is usually caused by either null values being returned for columns not set to AllowDBNull, or duplicate rows being returned with the same primary key.我想说的是,我的数据库中字段 FName确实设置不能为空.但是我奇怪的是,我的数据库中,命名有那个数据,用强数据类型却返回空.何解? 用 Linq的话,是没有问题(可以获取).
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