linq To SQl之多表联合查询_linqservermodedatasourceselecteventargs-优快云博客

本文链接：https://blog.youkuaiyun.com/longer123123/article/details/3954467

本文介绍了两种使用LINQ进行多表联合查询的方法。第一种是在数据控件绑定时，通过LINQ Server Mode DataSource进行查询，将角色表与父角色表连接，并过滤出未删除的角色。第二种是在普通绑定方法中设置联合主键，通过三个表（用户组别、用户、用户组）的连接获取详细用户信息。

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方法一：数据控件绑定

protected void LinqServerModeDataSource1_Selecting(object sender, DevExpress.Data.Linq.LinqServerModeDataSourceSelectEventArgs e)
{

            ASPxGridView1.KeyFieldName = "RoleID";
            e.KeyExpression = "RoleID";
            e.QueryableSource = from r1 in eDataContext.Role
                                join r2 in eDataContext.Role on r1.ParentRoleID equals r2.RoleID
                                where r1.IsDeleted == false
                                select new { ParentRoleID = r1.ParentRoleID, RoleID = r1.RoleID, RoleName = r1.RoleName, RoleDesc = r1.RoleDesc, ParentRoleName = r2.RoleName };

}

方法二：普通绑定方法中设置联合主键（用户组别编号和用户编号组合而成）

        Casagroup.Entities.EntitiesDataContext eDataContext = new Casagroup.Entities.EntitiesDataContext();
        Common _common = new Common();
        private void BindUserInfo()
        {
            UserGroup c = new UserGroup();

            //联合查询用户信息
            var result = from ugu in eDataContext.UserGroupUser
                         join us in eDataContext.User on ugu.UserID equals us.UserID
                         join ug in eDataContext.UserGroup on ugu.UserGroupID equals ug.UserGroupID
                         select new { ID = ugu.ID + "_" + us.UserID, UserPWD = us.UserPWD, UserGroupID = ugu.UserGroupID, UserID = us.UserID, UserName = us.UserName, UserGroupName = ug.UserGroupName, IsEnabled = us.IsEnabled };

this.gvUser.DataSource = result;
this.gvUser.DataBind();

}