Entity Framework Codefirst approach - entity-framework-5

Question

Am Using EntityFramework codefirst approach.my coding is
class Blog
{
[Key]
public int BlobId { get; set; }
public string Name { get; set; }
public virtual List<Post> Posts { get; set; }
}
class Post
{
[Key]
public int PostId { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public int BlobId { get; set; }
public virtual Blog Blob { get; set; }
}
class BlogContext:DbContext
{
public BlogContext() : base("constr") { }
public DbSet<Blog> Blogs { get; set; }
public DbSet<Post> Posts { get; set; }
}
class Program
{
static void Main(string[] args)
{
using (var db = new BlogContext())
{
Console.WriteLine("Enter a name for a new blob:");
var name = Console.ReadLine();
var b = new Blog { Name = name };
db.Blogs.Add(b);
db.SaveChanges();
Till this step i created two tables(Blogs and Posts)in my SQlserver.The BlobId is primary key in Blogs table.and foreign key in Posts table.and Blogid in blog table is auto incremented.postid in posts table is also auto incremented
class Program
{
static void Main(string[] args)
{
using (var db = new BlogContext())
{
Console.WriteLine("Enter a name for a new blob:");
var name = Console.ReadLine();
var b = new Blog { Name = name };
db.Blogs.Add(b);
db.SaveChanges();
Here i added name in the blogtable
var id1 = from val in db.Blogs
where val.Name == name
select val.BlobId;
Now by using Name am obtaining the blogid of blogs table
Console.WriteLine("Enter Title:");
var title = Console.ReadLine();
Console.WriteLine("Enter Content");
var content = Console.ReadLine();
var c = new Post { Title = title, Content = content, BlobId = id1};
db.Posts.Add(c);
db.SaveChanges();
here am reading the data for title,content.Then adding the title,content and blogid(which i obtained from another table) into Posts table
I getting error at BlobId = id1
Am getting Cannot implicitly convert type 'System.Linq.IQueryable' to 'int' this error
}
Console.ReadLine();
}
}
Can you help me to solve this.If you did not understand what i explained please reply me

Answer 1

The following query is a sequence of elements, not a scalar value, even though you believe that there is only one result, it is still a collection with one element when the results of the query are iterated over:
var id1 = from val in db.Blogs
where val.Name == name
select val.BlobId;
Change this to:
int id1 = (from val in db.Blogs
where val.Name == name
select val.BlobId).First();
This query will execute immediately and return the first element in the sequence. It will throw an exception if there is no match, so you may want to use FirstOrDefault and assign to a nullable int instead.