selective get and delete posts from database
-
30-04-2021 - |
题
In my windows phone 7 app i have database-class generated by sqlmetal. in addition, i have class that helps to work with this database.
public static IList<Task> GetTasks()
{
IList<Task> tasks = new List<Task>();
using (var context = new MyDBContext(ConnectionString))
{
tasks = (from emp in context.Tasks select emp).ToList();
}
return tasks;
}
this code return all posts from the database.
My questions:
- 1) How I can get posts, for example, only with a specific date (datetime) or ID(int)?
- 2) Is there any way to delete posts from the database?
解决方案
Try this:
tasks = from emp in context.Tasks
where emp.ID == yourId
select emp;
To delete posts from te databse use DeleteOnSubmit(entity)
method like:
context.Tasks.Attach(entityToDelete);
context.Tasks.DeleteOnSubmit(entityToDelete);
context.SubmitChanges();
其他提示
1) You should add 'where' to your LINQ statement. Like this:
from emp in context.Tasks select emp where emp.Date == new DateTime(2011, 11, 11)
2) To delete posts from database you should do three simple steps:
Get posts you want to delete from db
tasks = from emp in context.Tasks select emp where emp.Date > new DateTime(2011, 11, 11)
Call DeleteAllOnSubmit method of your DataContext object with our tasks to delete
dbContext.DeleteAllOnSubmit(tasks);
Call SubmitChahges method of your DataContext object.
dbContext.SubmitChanges();
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