<riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:rb_struc, CreateList=true}" 
                                      Height="0" Name="rb_strucDomainDataSource" QueryName="GetRb_strucQuery" 
                                      Width="0" Margin="0,0,360,479">
                <!--="z_plan_nameDomainDataSource_LoadedData"-->
            <riaControls:DomainDataSource.DomainContext>
                <my:myContext />
            </riaControls:DomainDataSource.DomainContext>
            <!--Фильтр загружаемых записей-->
        </riaControls:DomainDataSource>

        <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:z_institute, CreateList=true}" 
                                      Height="0" Name="z_instituteDomainDataSource" 
                                      QueryName="GetZ_instituteQuery" Width="0" 
                                      Margin="0,0,360,479">

Таблица  1        Таблица  2 
ind  name        ind  index_1   name_2       
 1     a               1      1             Null 
 2     b               2      2             q
 3     c               3      3             w

ind  name       
 2     b              
 3     c              

   public IQueryable<rb_struc> GetRb_struc()
        {
            return this.ObjectContext.rb_struc;
        }

SELECT  rb_struc.indx, rb_struc.name
  FROM [Store].[dbo].rb_struc INNER JOIN [Store].[dbo].z_institute on 
([Store].[dbo].z_institute.indxrb=[Store].[dbo].rb_struc.indx) and ([Store].[dbo].z_institute.[delete]='delete');  

IEnumerable<EmployeeDetails> matches;
matches = from employee in employees
          select employee;

    public IEnumerable<rb_struc> GetRb_struc() 
        {
        return this.ObjectContext.rb_struc;
        }

(r => r.z_institute.delete == "delete")

protected void Page_Load(object sender, EventArgs e) 
        { 
            using (NorthwindEntities context=new NorthwindEntities()) 
            { 
                GridView1.DataSource = context.TenExpensiveProducts(); 
                GridView1.DataBind(); 
            } 
        } 

using (StoreEntities4 context=new StoreEntities4())