根據LINQ中插入記錄的ID更新記錄到SQL

Question

我想插入一條記錄，然後根據插入記錄的scope_identity更新記錄。 我正在這樣做，但是當我想更新我的記錄時遇到錯誤。

WorkshopDataContext Dac = new WorkshopDataContext(); 
Dac.Connection.ConnectionString = "Data Source=dpsxxx-xxx;Initial Catalog=kar;User ID=sa;Password=xxxx"; 
Tbl_workshop Workshop = new Tbl_workshop(); 
Workshop.StateCode = Bodu.BduStateCode; 
Workshop.CityCode = Bodu.BduCityCode; 
Workshop.Co_workshop=12222; 
Dac.Tbl_workshop.InsertOnSubmit(Workshop); 
Dac.SubmitChanges(); 
Int64 Scope = Workshop.id; 
var query = from record in Dac.Tbl_workshop where record.id == Scope select record; 
     query.First().co_Workshop = Scope; 
Dac.SubmitChanges(); 

，這是錯誤：

Value of member 'co_Workshop' of an object of type 'Tbl_Workshop' changed. 
A member defining the identity of the object cannot be changed. 
Consider adding a new object with new identity and deleting the existing one instead. 

Answer 1

由於它的錯誤說，你不能改變co_Workshop因爲其身份（自動增加值）。要自由編輯它，您需要編輯數據庫並刪除此設置。

可能發生的情況是id和co_Workshop都被設置爲身份。只需從co_Workshop中禁用身份複選框即可。

Answer 2

如果你已經正確配置您的LINQ到SQL模型來反映你的表格中IDENTITY列，你應該有新的價值可右後.SubmitChanges()：

Tbl_workshop Workshop = new Tbl_workshop(); 
Workshop.StateCode = Bodu.BduStateCode; 
Workshop.CityCode = Bodu.BduCityCode; 
Workshop.Co_workshop=12222; 

Dac.Tbl_workshop.InsertOnSubmit(Workshop); 
Dac.SubmitChanges(); 

Int64 workshopID = Workshop.Id; // you should get new ID value here - automatically!! 

你不需要做例如從SQL Server讀取新值或任何東西 - Linq-to-SQL應自動更新您的Workshop對象的正確值。

更新：更新您的co_workshop值由IDENTITY ID給出的值，這樣做（只設置的co_workshop值，並再次保存 - 這就是所有要做的）：

Dac.Tbl_workshop.InsertOnSubmit(Workshop); 
Dac.SubmitChanges(); 

Int64 workshopID = Workshop.Id; // you should get new ID value here - automatically!! 

Workshop.Co_workshop = workshopID; 
Dac.SubmitChanges();