SPFieldLookup.PrimaryFieldId 属性

项目
05/13/2015

获取或设置标识主查找字段（如果字段是依赖型查阅字段的 GUID 的字符串表示形式。

命名空间： Microsoft.SharePoint
程序集： Microsoft.SharePoint（位于 Microsoft.SharePoint.dll 中）

语法

声明
Public Property PrimaryFieldId As String
    Get
    Set
用法
Dim instance As SPFieldLookup
Dim value As String

value = instance.PrimaryFieldId

instance.PrimaryFieldId = value

public string PrimaryFieldId { get; set; }

属性值

类型：System.String
如果字段中的多列查找的辅助字段，此属性返回的字符串表示形式的 GUID 来标识主查找字段。否则，它将返回空字符串。

异常

异常	条件
SPException	该设置后，不能更改此属性的值。
NotSupportedException	字段所属的外部列表。

备注

当您创建多个列的查阅时，主字段是SPFieldLookup对象，建立了与源列表之间的关系。一个或多个辅助字段取决于关系到源列表的主字段。

如果当前的SPFieldLookup对象的IsDependentLookup属性返回true，则当前对象是辅助字段，其PrimaryFieldId属性将返回 GUID 的字符串表示形式的标识它所依赖的主查找字段。

示例

下面的示例是一个控制台应用程序，检查列表，寻找SPFieldLookup的对象相关联的字段的集合。当它找到一个时，在应用程序中的代码将确定对象是否表示一个主要或次要的列。如果该对象表示第二列，该代码将使用由PrimaryFieldId属性返回的值以获取主列的显示名称。

using System;
using Microsoft.SharePoint;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            using (SPSite siteCollection = new SPSite("https://localhost"))
            {
                using (SPWeb site = siteCollection.OpenWeb())
                {
                    SPList list = site.Lists["Complete Orders"];

                    foreach (SPField item in list.Fields)
                    {
                        if (item is SPFieldLookup)
                        {
                            SPFieldLookup field = (SPFieldLookup)item;

                            if (!String.IsNullOrEmpty(field.LookupList) && !String.IsNullOrEmpty(field.LookupField))
                            {
                                // Is this the primary or secondary field for a list relationship? 
                                string strRelationship = field.IsRelationship ? "Primary":"Secondary"; 

                                // Print the display name of the field.
                                Console.WriteLine("\nField: {0} ({1} Field)", field.Title, strRelationship);

                                // Is this a secondary field in a list relationship?
                                if (field.IsDependentLookup)
                                {
                                    SPField primaryField = list.Fields[new Guid(field.PrimaryFieldId)];
                                    Console.WriteLine("Primary Field: {0}", primaryField.Title);
                                }
                            }
                        }
                    }
                }
            }
            Console.Write("\nPress ENTER to continue...");
            Console.ReadLine();
        }
    }
}

Imports System
Imports Microsoft.SharePoint

Module ConsoleApp

    Sub Main()
        Using siteCollection As New SPSite("https://localhost")
            Using site As SPWeb = siteCollection.OpenWeb()
                Dim list As SPList = site.Lists("Pending Orders")

                For Each item As SPField In list.Fields
                    If TypeOf item Is SPFieldLookup Then
                        Dim field As SPFieldLookup = DirectCast(item, SPFieldLookup)

                        If Not String.IsNullOrEmpty(field.LookupList) AndAlso Not String.IsNullOrEmpty(field.LookupField) Then
                            ' Is this the primary or secondary field for a list relationship?
                            Dim strRelationship As String = If(field.IsRelationship, "Primary", "Secondary")

                            ' Print the display name of the field.
                            Console.WriteLine(vbLf & "Field: {0} ({1} Field)", field.Title, strRelationship)

                            ' Is this a secondary field in a list relationship?
                            If field.IsDependentLookup Then
                                Dim primaryField As SPField = list.Fields(New Guid(field.PrimaryFieldId))
                                Console.WriteLine("Primary Field: {0}", primaryField.Title)
                            End If
                        End If
                    End If
                Next
            End Using
        End Using
        Console.Write(vbLf & "Press ENTER to continue...")
        Console.ReadLine()
    End Sub
End Module