How to Update with LINQ?
currently, I'm doing an update similar to as follows, because I can't see a better way of doing it. I've tried suggestions that I've read in blogs but none work, such as
http://msdn.microsoft.com/en-us/library/bb425822.aspx
and http://weblogs.asp.net/scottgu/archive/2007/05/19/using-linq-to-sql-part-1.aspxMaybe these do work and I'm missing some point. Has anyone else had luck with them?
// please note this isn't the actual code.
// I've modified it to clarify the point I wanted to make
// and also I didn't want to post our code here!
public bool UpdateMyStuff(int myId, List<int> funds)
{
// get MyTypes that correspond to the ID I want to update
IQueryable<MyType> myTypes =
database.MyTypes.Where(xx => xx.MyType_MyId == myId);
// delete them from the database
foreach (db.MyType mt in myTypes)
{
database.MyTypes.DeleteOnSubmit(mt);
}
database.SubmitChanges();
// create a new row for each item I wanted to update, and insert it
foreach (int fund in funds)
{
database.MyType mt = new database.MyType
{
MyType_MyId = myId,
fund_id = fund
};
database.MyTypes.InsertOnSubmit(mt);
}
// try to commit the insert
try
{
database.SubmitChanges();
return true;
}
开发者_Python百科 catch (Exception)
{
return false;
throw;
}
}
Unfortunately, there isn't a database.MyTypes.Update()
method so I don't know a better way to do it. Can sombody suggest what I could do? Thanks.
..as a side note, why isn't there an Update()
method?
Eh?
public void UpdateCustomer(int CustomerId, string CustomerName)
{
using (MyDataContext dc = new MyDataContext)
{
//retrieve an object from the datacontext.
// datacontext tracks changes to this instance!!!
Customer customer = dc.Customers.First(c => c.ID = CustomerId);
// property assignment is a change to this instance
customer.Name = CustomerName;
//dc knows that customer has changed
// and makes that change in the database
dc.SubmitChanges();
}
}
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