使用SilverLight从2个SQL表中删除Linq-to-SQL

Question

我在SQL中有两个表都有一个名为Selection_ID的字段。我想使用Linq-to-SQL删除所有包含Selection_ID = inpSelectionID的行。

我的表：

我的C＃功能：

void buttonDeleteSelectionList_Click(object sender, RoutedEventArgs e, Canvas canvasAdvancedSearchFieldResults, int inpSelectionID) 
{ 

    PositionServiceReference.PositionServiceClient service = new PositionServiceReference.PositionServiceClient(); 
    service.DeleteSelectionCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(service_DeleteSelectionCompleted); 
    service.DeleteSelectionAsync(inpSelectionID); 
} 

我的服务代码PositionService.svc.cs：

[OperationContract] 
void DeleteSelection(int inpSelectionID) 
{ 
    PositionDataClassesDataContext context = new PositionDataClassesDataContext(); 

    context.Lloyds_Selection.DeleteOnSubmit(inpSelectionID); 
    context.SubmitChanges(); 

    context.Lloyds_Selection_Vessels.DeleteOnSubmit(inpSelectionID); 
    context.SubmitChanges(); 
} 

Answer 1

DeleteOnSubmit requi将实体对象留作参数，因此如果不先从数据库中选择它，则无法删除该项目。也有DeleteAllOnSubmit方法，但它也需要IEnumerable实体。您可以使用它像：

context.Lloyds_Selection.DeleteAllOnSubmit(context.Lloyds_Selection.Where(l => l.Selection_ID == inpSelectionID)); 

但是，您可以使用DataContext.ExecuteCommand执行原始的SQL对数据库：

string command = string.format("DELETE FROM Lloyds_Section WHERE Selection_ID = {0}", inpSelectionID"); 
context.ExecuteCommand(command);