?CAML（Collaborative Application Markup Language）——協作應用程序標記語言，在調用WSS提供的諸多Web Service時進行數據查詢的一組XML規范，通過這種規范組織查詢語句進行數據的檢索。我在這里不想再具體介紹CAML的使用規范和具體語法了，讀者在MSDN或者園子里的其它文章中都可以了解到。

http://msdn.microsoft.com/zh-cn/library/ms462365.aspx

http://www.cnblogs.com/shanqian/archive/2008/09/25/859513.html

??? 這里我想給出我在項目實際應用中所積累的有關使用CAML查詢語句時所解決的問題。

1. Sharepoint的List中允許創建Document和Folder兩種類型的數據，在查詢時如何查出非Folder類型的數據？

1?<Query>?
2???<Where>?
3??????<Neq>?
4????????<FieldRef?Name="ContentType"/>?
5????????<Value?Type="Text">Folder</Value>?
6??????</Neq>?
7???</Where>?
8?</Query>

??? 當服務器上安裝有WSS的多語言包時，根據不同的語言ContentType的值也會有不同的寫法，可以借助CAML工具或者在WSS查詢返回的報文中查看一下，確認ContentType的具體類型名稱。

2. 如何查詢List中Lookup類型的字段的值？

??? Loopup類型的字段在數據庫中相當于外鍵，數據格式如1;#title1;#2;#title2，查詢時可以按照下面的CAML。

1?<Query>??
2?<Where>??
3???<Eq>??
4????<FieldRef?Name="ProjectID"?/>??
5????<Value?Type="Lookup">My Test Project 1</Value>??
6???</Eq>??
7?</Where>??
8?</Query> ??????? Value中只需要填寫外鍵所對應的名稱，而不用填寫外鍵所對應的id。如果只知道id而不知道名稱則可以使用下面的CAML。 1?<Query>??
2?????<Where>??
3?????<Eq>??
4?????????<FieldRef?Name="ProjectID"?LookupId="TRUE"?/>??
5?????????<Value?Type="Text">3</Value>??
6?????</Eq>??
7?????</Where>??
8?</Query>

3.?Lists.GetListItems()方法中的參數。

??? 對于該方法中參數的詳解，讀者可以參考MSDN：

http://msdn.microsoft.com/zh-cn/library/websvclists.lists.getlistitems.aspx

??? 這里對參數的幾點用法做一些說明：

listName	要查詢的List的名稱，也可以為List的GUID，不能為空。
viewName	一般都為空。
query	標準CAML查詢語句，可以為空，<Query></Query>
viewFields	要查詢的字段，可以為空，<ViewFields></ViewFields>
rowLimit	返回的記錄條數，默認為100，如果不需要限制，將值設為0 。
queryOptions	查詢選項設置，所涉及到的選項比較多，可以參考MSDN。? http://msdn.microsoft.com/zh-cn/library/websvclists.lists.getlistitems.aspx? 如果要查詢List中Folder下的文檔，則必須添加遞歸選項。? <QueryOptions>? ?? <ViewAttributes Scope="Recursive" />? </QueryOptions>
webID	可選參數。具體用法查看MSDN。

??? List的GUID可以通過調用Lists.GetListAndView()方法，在返回的報文中獲取到。

http://msdn.microsoft.com/zh-cn/library/websvclists.lists.getlistandview.aspx

4.?搜集到的List中字段的屬性，包括字段的Type。

ID	The ID is a globally unique identifier (GUID) which you should generate for each field. This ID will be used in lists when referencing the site column
Type	The type indicates the data type of the column and can be of the any following:
	AllDayEvent	The all day event flag is used in calendar lists.
	Attachments	The URL of an attachment.
	Boolean	A boolean indicator with Yes/No.
	Calculated	Indicates that the column is a calculated column based on a expression.
	Choice	Indicates that the column is choice from a list of items
	Computed	Indicates the field's value is dependant on another field's value.
	ContentTypeId	A Content Type ID value.
	Counter	An internal unique ID's / counter for each item.
	Currency	A currency value (its format depends on the locale).
	DateTime	A Date and Time field.
	File	A file object when used in document libraries.
	GridChoice	A rating scale as used in surveys
	Guid	A globally unique identifier.
	Integer	An integer number field.
	Lookup	The field is a lookup which is a choice, however the choice is from another list.
	LookupMulti	A lookup field, however multiple selections are allowed.
	ModStat	An approval status.
	MultiChoice	A choice field, however multiple selections are allowed
	Note	Multiple lines of text which can be plain or formatted.
	Number	A numerical field which allows decimal places.
	PageSeparator	A page separator field, for surveys.
	Recurrence	An indicator that identifies the field as a reoccurring calendar event.
	Text	A single line of text
	ThreadIndex	The ID of a discussion thread.
	Threading	Indicates the field supports threading (in discussions).
	URL	A Unified Resource Locator (URL) is stored.
	User	A person or group.
	UserMulti	A person or group, however multiple people or groups can be selected.
	WorkflowEventType	Contains the type of workflow history event (used in workflow history list).
	WorkflowStatus	The status of a workflow is stored.
Title	The name of the field as displayed in the user interface.? This title may be set using a resource file.
Name	(optional) The name of the field which should be guaranteed to never change.? The default is the Title with spaces and invalid characters removed.
StaticName	(optional) The logical name of the field which is similar to Name, however this can be programmatically changed.
DisplayName	(optional) See title.
Description	(optional) A description of the field which will be displayed in front ends.? The description can be placed into a resource file.
Required	(optional) Indicates whether or not the field is mandatory. The default is FALSE.
MaxLength	(optional) The maximum number of characters allowed.
Hidden	(optional) Indicates that the field should be hidden from the interface. If TRUE, this field will not be shown on views or forms. The default is FALSE.
Readonly	(optional) The field should be read-only and can be displayed and not edited.? The default is FALSE.
ShowInDisplayForm	(optional) Indicates whether the field should be shown on a display form. The default is TRUE.
ShowInEditForm	(optional) Indicates whether the field should be shown on an edit form. The default is TRUE.
ShowInListSettings	(optional) Indicates whether the field should be shown in the list settings screen. The default is TRUE.
ShowInNewForm	(optional) Indicates whether the field should be shown on a New form. The default is TRUE.
ShowInVersionHistory	(optional) Indicates whether the field should be shown in the version history of an item. The default is TRUE.
ShowInViewForms	(optional) Indicates whether the field should be shown on a view form. The default is TRUE.
Group	(optional) A group name allowing you to group fields together.

5.?Customer List中的列名變化？

??? 在Customer List中創建一個新列時，Sharepoint同時給它賦予了內部名稱（FieldInternalName）和外部名稱（FieldName），初始狀態下內部名稱和外部名稱是相同的，當我們修改了List的列名時，外部名稱被修改了，而內部名稱則不變，為了防止在使用時出現找不到列的錯誤，必須在CAML中使用內部名稱作為列名。可以借助CAML工具查找列的內部名稱，也可以在List的新建記錄頁面中查看源代碼，搜索顯示的列名，找到類似于下面的代碼段，FieldInternalName的值即為該列的內部名稱。

<!--?FieldName="Area"?
??? FieldInternalName="Title"?
??? FieldType="SPFieldText"?
-->

6.?兩個小工具，用于檢測或生成CAML，對List的管理和查看報文的具體信息。實際項目應用中會很有用哦:)

U2U Caml Query Builder 2007 v3.1.0.0 (windows version)

Sharepoint Manager 2007

??? CAML的使用過程中還是會遇到很多問題的，以后遇到再逐漸補上吧！

本文轉自Jaxu博客園博客，原文鏈接：http://www.cnblogs.com/jaxu/archive/2009/03/23/1419717.html，如需轉載請自行聯系原作者

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