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I was searching the net for a simple example of a create,edit, delete with Linq-to-Entities, I eventually found but it was too elaborate, so I thought I would give my 2 cents worth and give a simple example. When I embarked on my learning mission of Linq-to-Entities it was to simplify my life, sometimes I wonder if this was the case, I still love Linq though.
Creating a new record is as easy as this:
using (DataEntities db = new DataEntities())
{
//Create a new NewsItem
var newsItem = new NewsItem();
//Assign values
newsItem.Headline = this.txtHeadline.Text.Trim();
newsItem.PublishedDate = Convert.ToDateTime(this.txtPublishDate.Text.Trim());
newsItem.Active = this.cbActive.Checked;
newsItem.Synopsis = this.txtSynopsys.Text.Trim();
newsItem.Content = this.edContent.Text;
newsItem.Author = this.txtAuthor.Text.Trim();
//Add the new item to the set
db.AddToNewsSet(_news);
//Commit the changes
db.SaveChanges();
}
Editing a record is slightly more complicated, first you have to have the record if it is not persisted as is the case in ASP.NET.
using (DataEntities db = new DataEntities())
{
//Get the NewsItem for editing
var newsItem = ((from NewsItem in db.NewsSet
where NewsItem.ID == newsID
select NewsItem)
.FirstOrDefault());
//Assign values
newsItem.Headline = this.txtHeadline.Text.Trim();
newsItem.PublishedDate = Convert.ToDateTime(this.txtPublishDate.Text.Trim());
newsItem.Active = this.cbActive.Checked;
newsItem.Synopsis = this.txtSynopsys.Text.Trim();
newsItem.Content = this.edContent.Text;
newsItem.Author = this.txtAuthor.Text.Trim();
//Commit the changes
db.SaveChanges();
}
Lastly, deleting a record
using (DataEntities db = new DataEntities())
{
//Get the NewsItem for editing
var newsItem = ((from NewsItem in db.NewsSet
where NewsItem.ID == newsID
select NewsItem)
.FirstOrDefault());
//Set the record for deletion from the database
db.DeleteObject(newsItem);
//Commit the changes
db.SaveChanges();
}
As can be seen there are no complications and Linq just does it.
In my next Linq article I will be talking about relational data editing.