//查詢並顯示資料
static void DisplayData()
{
//這裡的db是指EF的DbContext,而非SQL Server的db資料庫
using (var db = new BlogContext())
{
Console.WriteLine("\n顯示所有Users:");
Console.WriteLine("==========================");
//以LINQ查詢
var allUsers = from u in db.Users
select u;
foreach (var item in allUsers)
{
Console.WriteLine($"{item.UserId}, {item.UserName}, {item.Email}");
}
Console.WriteLine("\n顯示某些條件的Users:");
Console.WriteLine("==========================");
//以LINQ查詢,過濾與排序
var filter = from u in db.Users
where u.UserId >= 2 && u.UserId <= 5
orderby u.UserName descending
select u;
foreach (var item in filter)
{
Console.WriteLine($"{item.UserId}, {item.UserName}, {item.Email}");
}
Console.WriteLine("\n顯示指定的Users:");
Console.WriteLine("==========================");
var specificUsers = db.Users.ToList();
//在ForEach()方法中做判斷
specificUsers.ForEach(x =>
{
if (x.UserName.Contains("祭司") || x.UserName == "Mary" || x.UserName == "John")
{
Console.WriteLine($"{x.UserId}, {x.UserName}, {x.Email}");
}
});
Console.WriteLine("\n顯示所有Blogs:");
Console.WriteLine("==========================");
var allBlogs = from b in db.Blog
select b;
allBlogs.ToList().ForEach(b =>
{
Console.WriteLine($"{b.BlogName}, {b.Url}, Owner: {b.User.UserName}");
});
Console.WriteLine("\n顯示所有Posts貼文:");
Console.WriteLine("==========================");
var allPosts = from u in db.Post
select u;
allPosts.ToList().ForEach(p =>
{
Console.WriteLine($"{p.PostId}, {p.Title}, {p.Content}, " +
$"BlogBlogId : {p.BlogBlogId}, BlogName: {p.Blog.BlogName}");
});
}
Console.WriteLine("");
Console.WriteLine("請按任意鍵離開...");
Console.ReadKey();
}
//以AddRange()方法新增Entity資料
static void AddRangeData()
{
//建立List集合
List <User> users = new List <User>
{
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
}
};
List <Blog> blogs = new List <Blog>
{
new Blog {
BlogName = "John's Blog", Url = "http://www.johnblog.com", UserUserId = 7
},
new Blog {
BlogName = "Tom's Blog", Url = "http://www.tomblog.com", UserUserId = 8
},
new Blog {
BlogName = "Rose's Blog", Url = "http://www.roseblog.com", UserUserId = 9
},
new Blog {
BlogName = "Code Magic碼魔法", Url = "http://www.codemagic.com.tw", UserUserId = 1
}
};
List <Post> posts = new List <Post>
{
new Post {
Title = "I am John.", Content = "I love Bootstrap!", BlogBlogId = 7
},
new Post {
Title = "I am Tom.", Content = "I love jQuery!", BlogBlogId = 8
},
new Post {
Title = "I am Rose.", Content = "I love HTML5!", BlogBlogId = 9
}
};
//將List加入到Entity集合
using (var ctx = new BlogContext())
{
//檢查UserId為7的資料是否存在?若無則新增資料
var user = ctx.Users.Find(7);
if (user == null)
{
ctx.Users.AddRange(users);
ctx.SaveChanges(); //呼叫SaveChanges()儲存異動
ctx.Blog.AddRange(blogs);
ctx.SaveChanges();
ctx.Post.AddRange(posts);
ctx.SaveChanges();
}
else
{
Console.WriteLine("樣本資料己存在, 不新增資料");
return;
}
}
Console.WriteLine("AddRange()執行完成,請按任意鍵離開...");
Console.ReadKey();
}
//以foreach(){ Add()方法}新增Entity資料
static void AddDataBasic()
{
//建立List泛型集合, 將User Entity加入集合中
List <User> users = new List <User>
{
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
}
};
List <Blog> blogs = new List <Blog>
{
new Blog {
BlogName = "DotNet開發聖殿", Url = "http://www.dotnetblog.com.tw", UserUserId = 1
},
new Blog {
BlogName = "David's Blog", Url = "http://www.davidblog.com", UserUserId = 2
},
new Blog {
BlogName = "Mary's Blog", Url = "http://www.maryblog.com", UserUserId = 3
}
};
List <Post> posts = new List <Post>
{
new Post {
Title = "I am 聖殿祭司.", Content = "I love Mvc!", BlogBlogId = 1
},
new Post {
Title = "I am David.", Content = "I love Entity Framework!", BlogBlogId = 2
},
new Post {
Title = "I am Mary", Content = "I love Razor!", BlogBlogId = 3
}
};
//初始DbContext資料庫環境物件
BlogContext context = new BlogContext();
//檢查資料是否存在, 若無則新增資料
if (context.Users.Any())
{
Console.WriteLine("樣本資料己存在, 不新增資料");
return;
}
//將資料加入到Users實體中
foreach (var item in users)
{
context.Users.Add(item);
}
context.SaveChanges(); //呼叫SaveChanges()儲存異動
Console.WriteLine("Users資料新增完成.");
//將資料加入到Blogs實體中
foreach (var item in blogs)
{
context.Blog.Add(item);
}
context.SaveChanges();
Console.WriteLine("Blogs資料新增完成.");
//將資料加入到Posts實體中
foreach (var item in posts)
{
context.Post.Add(item);
}
context.SaveChanges();
//也可以用苦力語法建立單一筆Entity資料
Post post = new Post();
post.Title = "I am 祭司.";
post.Content = "I love sports!";
post.BlogBlogId = 1;
context.Post.Add(post);
context.SaveChanges();
//或者用聰明一點的物件初始化語法建立Entity
var easyPost = new Post {
Title = "I am 奚江華.", Content = "I love coding!", BlogBlogId = 1
};
context.Post.Add(easyPost);
context.SaveChanges();
Console.WriteLine("Posts資料新增完成.");
Console.WriteLine("AddDataBasic()執行完成, 請按任意鍵離開...");
Console.ReadKey();
context.Dispose(); //關閉資料庫所佔連線
}
//以List<T>.Foreach(x=>{ Add()方法})新增Entity資料
static void AddData()
{
//建立List集合
List <User> users = new List <User>
{
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
},
new User {
UserName = "******", Email = "*****@*****.**"
}
};
List <Blog> blogs = new List <Blog>
{
new Blog {
BlogName = "Bob's Blog", Url = "http://www.bobblog.com.tw", UserUserId = 4
},
new Blog {
BlogName = "Johnson's Blog", Url = "http://www.johnsonblog.com", UserUserId = 5
},
new Blog {
BlogName = "Lucy's Blog", Url = "http://www.lucyblog.com", UserUserId = 6
}
};
List <Post> posts = new List <Post>
{
new Post {
Title = "I am Tony.", Content = "I love JavaScript!", BlogBlogId = 4
},
new Post {
Title = "I am David.", Content = "I love jQuery Mobile!", BlogBlogId = 5
},
new Post {
Title = "I am Mary", Content = "I love LINQ!", BlogBlogId = 6
}
};
//將List加入到Entity集合
BlogContext ctx = new BlogContext();
///檢查UserId為4的資料是否存在?若無則新增資料
if (ctx.Users.Find(4) != null)
{
Console.WriteLine("樣本資料己存在, 不新增資料");
return;
}
users.ForEach(x => ctx.Users.Add(x));
ctx.SaveChanges(); //呼叫SaveChanges()儲存異動
Console.WriteLine("Users資料新增完成.");
blogs.ForEach(x => ctx.Blog.Add(x));
ctx.SaveChanges();
Console.WriteLine("Blogs資料新增完成.");
posts.ForEach(x => ctx.Post.Add(x));
ctx.SaveChanges();
Console.WriteLine("Posts資料新增完成.");
ctx.Dispose();
Console.WriteLine("AddData()執行完成,請按任意鍵離開...");
Console.ReadKey();
}