您当前的位置: 怎么我在编译器写代码LINQ方法参数提示看不懂啊，比如 GroupBy(Of TSource, TKey)(IQueryable(Of TSource), Expression(Of Func(Of TSource, TKey)))之类的，我都不知道到该传入什么参数？还有我想问下LINQ怎么左连接然后对数据读取？
------解决方案--------------------
left join:
- C# code
public void Linq105()
{
string[] categories = new string[]{
"Beverages",
"Condiments",
"Vegetables",
"Dairy Products",
"Seafood" };
List<Product> products = GetProductList();
var q =
from c in categories
join p in products on c equals p.Category into ps
from p in ps.DefaultIfEmpty()
select new { Category = c, ProductName = p == null ? "(No products)" : p.ProductName };
foreach (var v in q)
{
Console.WriteLine(v.ProductName + ": " + v.Category);
}
}
------解决方案--------------------
Group by
http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b