将晚期绑定实体类与 LINQ 查询结合使用

发布日期： 2017年1月

适用于： Dynamics 365 (online),Dynamics 365 (on-premises),Dynamics CRM 2016,Dynamics CRM Online

在 Microsoft Dynamics 365 和 Microsoft Dynamics 365 (online) 中，可以对 .NET 语言集成查询 (LINQ) 查询使用晚期绑定。 晚期绑定使用属性逻辑名称并且在运行时解析。

本主题内容

在 Join 子句中使用晚期绑定

在左联接中使用晚期绑定

使用晚期绑定和 Contains 方法

使用晚期绑定和不等于运算符

使用 GetAttributeValue 方法

在 Join 子句中使用晚期绑定

下面的示例演示如何在 LINQ 查询的 join 子句中使用晚期绑定。

检索表示客户主要联系人和客户名称的联系人全名。

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
 var query_join2 = from c in orgSvcContext.CreateQuery("contact")
                   join a in orgSvcContext.CreateQuery("account")
                   on c["contactid"] equals a["primarycontactid"]
                   select new
                   {
                    contact_name = c["fullname"],
                    account_name = a["name"]
                   };
 foreach (var c in query_join2)
 {
  System.Console.WriteLine(c.contact_name + "  " + c.account_name);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim query_join2 = From c In orgSvcContext.CreateQuery("contact") _
                   Join a In orgSvcContext.CreateQuery("account") _
                   On c("contactid") Equals a("primarycontactid") _
                   Select New With {Key .contact_name = c("fullname"),
                                    Key .account_name = a("name")}
 For Each c In query_join2
  Console.WriteLine(c.contact_name.ToString() & "  " _
                    & c.account_name.ToString())
 Next c
End Using

检索联系人、客户和潜在顾客数据，其中潜在顾客为原始潜在顾客且联系人姓氏不是“Parker”

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
 var query_dejoin = from c in orgSvcContext.CreateQuery("contact")
                    join a in orgSvcContext.CreateQuery("account") 
                    on c["contactid"] equals a["primarycontactid"]
                    join l in orgSvcContext.CreateQuery("lead") 
                    on a["originatingleadid"] equals l["leadid"]
                    where (string)c["lastname"] != "Parker"
                    select new { Contact = c, Account = a, Lead = l };
 foreach (var c in query_dejoin)
 {
  System.Console.WriteLine(c.Account.Attributes["name"] + " " + 
   c.Contact.Attributes["fullname"] + " " + c.Lead.Attributes["leadid"]);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim query_dejoin = From c In orgSvcContext.CreateQuery("contact") _
                    Join a In orgSvcContext.CreateQuery("account")
                    On c("contactid") Equals a("primarycontactid") _
                    Join l In orgSvcContext.CreateQuery("lead") _
                    On a("originatingleadid") Equals l("leadid") _
                    Select New With {Key .Contact = c,
                                     Key .Account = a,
                                     Key .Lead = l}
 For Each c In query_dejoin
  Console.WriteLine(c.Account.Attributes("name").ToString() _
                    & " " _
                    & c.Contact.Attributes("fullname").ToString() _
                    & " " _
                    & c.Lead.Attributes("leadid").ToString())
 Next c
End Using

在左联接中使用晚期绑定

以下示例显示如何使用左联接检索联系人和客户信息列表。 左联接设计用于从两个源中返回具有和不具有子级的父级。 父与子之间存在关联，但实际上可能不存在任何子级。

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
 var query_join9 = from a in orgSvcContext.CreateQuery("account")
                   join c in orgSvcContext.CreateQuery("contact") 
                   on a["primarycontactid"] equals c["contactid"] into gr
                   from c_joined in gr.DefaultIfEmpty()
                   select new
                   {
                    account_name = a.Attributes["name"]
                   };
 foreach (var c in query_join9)
 {
  System.Console.WriteLine(c.account_name);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim query_join9 = From a In orgSvcContext.CreateQuery("account") _
                   Group Join c In orgSvcContext.CreateQuery("contact") _
                   On a("primarycontactid") Equals c("contactid") Into gr = _
                   Group From c_joined In gr.DefaultIfEmpty() _
                   Select New With {Key .account_name = a.Attributes("name")}
 For Each c In query_join9
  Console.WriteLine(c.account_name)
 Next c
End Using

使用晚期绑定和 Contains 方法

以下示例演示如何在 LINQ 查询中使用晚期绑定和 Contains 方法。

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
 var query_contains3 = from c in orgSvcContext.CreateQuery("contact")
                       where ((string)c["description"]).Contains("Coho")
                       select new
                       {
                        firstname = c.Attributes["firstname"],
                        lastname = c.Attributes["lastname"]
                       };
 foreach (var c in query_contains3)
 {
  System.Console.WriteLine(c.firstname + " " + c.lastname);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim query_contains3 = From c In orgSvcContext.CreateQuery("contact") _
                       Where (CStr(c("description"))).Contains("Coho") _
                       Select New With
                             {Key .firstname = c.Attributes("firstname"),
                             Key .lastname = c.Attributes("lastname")}

 For Each c In query_contains3
  Console.WriteLine(c.firstname.ToString() & " " _
                    & c.lastname.ToString())
 Next c
End Using

使用晚期绑定和不等于运算符

以下示例演示不等于运算符的用法。

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
 var query_ne3 = from c in orgSvcContext.CreateQuery("contact")
                 where !c["address1_city"].Equals(null)
                 select new
                 {
                  FirstName = c["firstname"],
                  LastName = c["lastname"],
                  Address1_City = c["address1_city"]
                 };
 foreach (var c in query_ne3)
 {
  System.Console.WriteLine(c.FirstName + " " + 
   c.LastName + " " + c.Address1_City);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim query_ne3 = From c In orgSvcContext.CreateQuery("contact") _
                 Where (Not c("address1_city").Equals(Nothing)) _
                 Select New With {Key .FirstName = c("firstname"),
                                  Key .LastName = c("lastname"),
                                  Key .Address1_City =
                                  c("address1_city")}
 For Each c In query_ne3
  Console.WriteLine(c.FirstName.ToString() & " " _
                    & c.LastName.ToString() & " " _
                    & c.Address1_City.ToString())
 Next c
End Using

使用 GetAttributeValue 方法

以下示例演示如何使用 GetAttributeValue 方法检索联系人信息。

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{

 var list_getattrib1 = (from c in orgSvcContext.CreateQuery("contact")
                        where c.GetAttributeValue<Guid?>("contactid") != _contactId1
                        select new { 
                         FirstName = c.GetAttributeValue<string>("firstname"), 
                         LastName = c.GetAttributeValue<string>("lastname") 
                        }).ToList();
 foreach (var c in list_getattrib1)
 {
  System.Console.WriteLine(c.FirstName + " " + c.LastName);
 }
}

Using orgSvcContext As New OrganizationServiceContext(_serviceProxy)
 Dim list_getattrib1 = ( _
     From c In orgSvcContext.CreateQuery("contact") _
     Where Not c.GetAttributeValue(Of Guid?)("contactid") _
     .Value.Equals(_contactId1) _
     Select New With
            {
             Key .FirstName = c.GetAttributeValue(Of String)("firstname"),
             Key .LastName = c.GetAttributeValue(Of String)("lastname")}
         ).ToList()
 For Each c In list_getattrib1
  Console.WriteLine(c.FirstName & " " & c.LastName)
 Next c
End Using

另请参阅

CreateQuery<TEntity>
使用 LINQ（.NET 语言集成查询）构建查询
将实体属性与 LINQ 结合使用的订单结果

Microsoft Dynamics 365

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