linq里lambda写的join查询，并附加动态拼接的条件，条件为enum类型的查询

因为查询条件不固定的原因，sql式的linq查询没法动态拼接条件。

网上搜的资料整理之后终于解决。

参考资料：

enum使用 http://blog.csdn.net/slowlifes/article/details/7799444

linq动态查询 http://msdn.microsoft.com/zh-cn/subscriptions/dd470085.aspx

lambda join使用 http://blog.csdn.net/lai_gb/article/details/4491843

 

　　　　　　　string whereParams = GetWhereParams(SolutionGroup, CapabilityType);



            var query = crm.new_usercapabilitynew_usercapabilities.Where(uc => uc.new_user == SystemUserId).

                Join(

                    crm.new_capabilitynew_capabilities,

                    uc => uc.new_capabilityid,

                    c => c.new_capabilityid,

                    (uc, c) => new

                        {

                            uc,

                            c

                        }

                ).Where(o => o.c.new_name.Contains(Capability)).Where(whereParams)

                .OrderBy(o => o.uc.new_capabilityidLabel)

                .Select(o => new

                {

                    new_capabilityid = o.uc.new_capabilityid,

                    new_usercapabilityid = o.uc.new_usercapabilityid,

                    new_capabilityidLabel = o.uc.new_capabilityidLabel,

                    new_developmentarea = o.uc.new_developmentarea,

                    new_rating = o.uc.new_rating

                });

　　　　 public string GetWhereParams(string SolutionGroup, string CapabilityType) 

        {

            var enumgroup = Enum.GetNames(typeof(Xrm.new_capability.NewSolutiongroup)).Where(e => e.ToLower().Contains(SolutionGroup.ToLower())).ToList();

            string groupLinqStr = "";

            if (enumgroup.Count > 0)

            {

                groupLinqStr += "(";

                for (int i = 0; i < enumgroup.Count; i++)

                {

                    Xrm.new_capability.NewSolutiongroup enumitem = (Xrm.new_capability.NewSolutiongroup)Enum.Parse(typeof(Xrm.new_capability.NewSolutiongroup), enumgroup[i]);

                    groupLinqStr += "c.new_solutiongroup = " + ((int)enumitem).ToString();

                    if (i != enumgroup.Count - 1)

                    {

                        groupLinqStr += " or ";

                    }

                }

                groupLinqStr += ")";

            }

            else if (!string.IsNullOrEmpty(SolutionGroup))

            {

                groupLinqStr += "c.new_solutiongroup = 0";

            }



            var enumtype = Enum.GetNames(typeof(Xrm.new_capability.NewCapabilitytype)).Where(e => e.ToLower().Contains(CapabilityType.ToLower())).ToList();

            if (enumtype.Count > 0)

            {

                if (groupLinqStr.Length > 0) groupLinqStr += " and ";

                groupLinqStr += "(";

                for (int i = 0; i < enumtype.Count; i++)

                {

                    Xrm.new_capability.NewCapabilitytype enumitem = (Xrm.new_capability.NewCapabilitytype)Enum.Parse(typeof(Xrm.new_capability.NewCapabilitytype), enumtype[i]);

                    groupLinqStr += "c.new_capabilitytype = " + ((int)enumitem).ToString();

                    if (i != enumtype.Count - 1)

                    {

                        groupLinqStr += " or ";

                    }

                }

                groupLinqStr += ")";

            }

            else if (!string.IsNullOrEmpty(CapabilityType))

            {

                if (groupLinqStr.Length > 0) groupLinqStr += " and ";

                groupLinqStr += "c.new_capabilitytype = 0";

            }

            return groupLinqStr;

        }