LINQ to DataSet需要使用System.Core.dll、System.Data.dll和System.Data.DataSetExtensions.dll，在项目中添加引用System.Data和System.Data.DataSetExtensions。

1. DataTable读取列表

DataSet ds = new DataSet();// 省略ds的Fill代码DataTable products = ds.Tables["Product"]; IEnumerable
     
       rows = from p in products.AsEnumerable() select p; foreach (DataRow row in rows) { Console.WriteLine(row.Field
      
       ("ProductName")); }
      
     

DataSet ds = new DataSet();// 省略ds的Fill代码DataTable products = ds.Tables["Product"]; var rows = products.AsEnumerable() .Select(p => new { ProductID = p.Field
     
      ("ProductID"), ProductName = p.Field
      
       ("ProductName"), UnitPrice = p.Field
       
        ("UnitPrice") }); foreach (var row in rows) { Console.WriteLine(row.ProductName); }
       
      
     

var products = ds.Tables["Product"].AsEnumerable();var query = from p in products select p.Field
     
      ("ProductName");
     

2. DataTable查询

var rows = products.AsEnumerable()    .Where(p => p.Field
     
      ("UnitPrice") > 10m) .Select(p => new { ProductID = p.Field
      
       ("ProductID"), ProductName = p.Field
       
        ("ProductName"), UnitPrice = p.Field
        
         ("UnitPrice") });
        
       
      
     

3. DataTable数据排序

var rows = products.AsEnumerable()    .Where(p => p.Field
     
      ("UnitPrice") > 10m) .OrderBy(p => p.Field
      
       ("SortOrder")) .Select(p => new { ProductID = p.Field
       
        ("ProductID"), ProductName = p.Field
        
         ("ProductName"), UnitPrice = p.Field
         
          ("UnitPrice") });
         
        
       
      
     

var expr = from p in products.AsEnumerable()            orderby p.Field
     
      ("SortOrder") select p; IEnumerable
      
        rows = expr.ToArray(); foreach (var row in rows) { Console.WriteLine(row.Field
       
        ("ProductName")); }
       
      
     

var expr = from p in ds.Tables["Product"].AsEnumerable() orderby p.Field
     
      ("SortOrder"), p.Field
      
       ("ProductName") descending select p;
      
     

4. 多个DataTable查询

var query = from p in ds.Tables["Product"].AsEnumerable() from c in ds.Tables["Category"].AsEnumerable() where p.Field
     
      ("CategoryID") == c.Field
      
       ("CategoryID") && p.Field
       
        ("UnitPrice") > 10m select new { ProductID = p.Field
        
         ("ProductID"), ProductName = p.Field
         
          ("ProductName"), CategoryName = c.Field
          
           ("CategoryName") };
          
         
        
       
      
     

5. DataTable分组

var query = from p in ds.Tables["Product"].AsEnumerable() group p by p.Field
     
      ("CategoryID") into g select new { CategoryID = g.Key, Products = g }; foreach (var item in query) { Console.WriteLine(item.CategoryID); foreach (var p in item.Products) { Console.WriteLine(p.Field
      
       ("ProductName")); } }
      
     

　　查询Product中每个CategoryID的数目：

var expr = from p in ds.Tables["Product"].AsEnumerable() group p by p.Field
     
      ("CategoryID") into g select new { CategoryID = g.Key, ProductsCount = g.Count() };
     

 

http://www.cnblogs.com/libingql/p/4045807.html