您可以这样做：

var query= from t1 in context.MY_TEST_TABLE1
           from t2 in context.MY_TEST_TABLE2
           where t1.firstname == t2.name
           select new { Table1Id= t1.ID, FirstName= t1.firstname, Table2Id=t2.ID,Name= t2.name};

在Linq to
Entities中进行交叉联接的另一种方法是使用SelectMany扩展方法：

var query= context.MY_TEST_TABLE1.SelectMany(
    t1=>context.MY_TEST_TABLE2
        .Where(t2=>t1.firstname == t2.name)
        .Select(t2=>new { 
            Table1Id= t1.ID,
            FirstName= t1.firstname, 
            Table2Id=t2.ID,
            Name= t2.name
        })
    );