Sharepoint学习笔记---Linq to Sharepoint--如何获取Linq Query 生成的CALM

   我们知道Linq to sharepoint 实际最终还是转化成了CALM来对Sharepoint进行访问,那么我们怎样才能知道我们编写的Query语句最终转化成的CALM语句是什么样子呢。 我们可以使用如下方法来达到我们的目的。

   1.首先在我们的Sharepoint项目中新建一个名为CAMLDebug的类，如图:

  

   CALMDebug.cs代码如下:  

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using Microsoft.SharePoint.Linq;

namespace NorthwindLinqToSP
{
    public class CAMLDebug : IDisposable
    {

        private DataContext _context;

        public StringWriter Writer
        {
            get;
            private set;
        }

        public CAMLDebug(DataContext context)
        {
            _context = context;
            Writer = new StringWriter();
            _context.Log = Writer;
        }

        public override string ToString()
        {
            Writer.Flush();
            return Writer.GetStringBuilder().ToString();
        }

        public void Dispose()
        {
            _context.Log = null;
            Writer.Dispose();
        }
    } 

}

   2.然后在我们的Linq to sharepoint 代码中使用此类  

            var dc = new NorthWindEntityDataContext(SPContext.Current.Web.Url);

            MyCustomers = dc.GetList<ACustomerItem>("ACustomer");
            MyOrders = dc.GetList<AOrdersItem>("AOrders");

            using (CAMLDebug debug = new CAMLDebug(dc))
            {
                string queries = debug.ToString();
                var query = from c in MyCustomers
                            where (from o in MyOrders
                                   select o.BCSFindCustomerID).Contains(c.BCSFindCustomerID)
                            select c;
                this.lblMsg2.Text = "Items :" + query.Count().ToString();

                this.gvDetails.DataSource = query;
                this.gvDetails.DataBind();
            }

   3.在代码段中设置断点，进入调试（当然，你也可以把queries保存的CALM字串输出到你想要的任何地方）

 

 

   4.此处，也有人不用上面的类，而直接使用如下代码把生成的CALM直接输出到指定的txt文件中进行查看。 

            var dc = new NorthWindEntityDataContext(SPContext.Current.Web.Url);
            MyCustomers = dc.GetList<ACustomerItem>("ACustomer");
            MyOrders = dc.GetList<AOrdersItem>("AOrders");

            TextWriter textWriter = new StreamWriter(@"c:\caml.txt", false);
            dc.Log = textWriter;

            var query = from c in MyCustomers
                        where !(from o in MyOrders
                                select o.BCSFindCustomerID).Contains(c.BCSFindCustomerID)
                        select new
                        {
                            CopanyName = c.BCSFindCompanyName,
                            ContanctName = c.BCSFindContactName,
                            Address = new
                            {
                                Country = c.BCSFindCountry,
                                City = c.BCSFindCity,
                                PostalCode = c.BCSFindPostalCode
                            }

                        };

            this.lblMsg2.Text = "Items :" + query.Count().ToString();
            this.gvDetails.DataSource = query;
            this.gvDetails.DataBind();

上述代码输出的结果如下图:

 

接下来的任务就是在你的SPQuery 中进行引用了(以下是一个引用样例，仅作参考)

SPQuery query = new SPQuery();
query.Query = @"<Where>
                    <And>
                    <BeginsWith>
                        <FieldRef Name='ContentTypeId' />
                        <Value Type='ContentTypeId'>0x0100</Value>
                    </BeginsWith>
                    <BeginsWith>
                        <FieldRef Name='ProductContentTypeId' />
                        <Value Type='Lookup'>0x0100</Value>
                    </BeginsWith>
                    </And>
                </Where>
                <OrderBy Override='TRUE' />";

query.ViewFields = @"<FieldRef Name='Title' />
                    <FieldRef Name='ProductProductName' />";
query.ProjectedFields = @"<Field Name='ProductProductName' Type='Lookup' 
                                 List='AProduct' ShowField='ProductName' />
                          <Field Name='ProductContentTypeId' Type='Lookup' 
                                 List='AProduct' ShowField='ContentTypeId' />";
query.Joins = @"<Join Type='INNER' ListAlias='AProduct'>
                <Eq>
                    <FieldRef Name='Product' RefType='ID' />
                    <FieldRef List='Product' Name='ID' />
                </Eq>
                </Join>";

query.RowLimit = 2657495668;
var list = web.Lists["AOrders"];
var items = list.GetItems(query);
foreach (SPListItem item in items)
{
   this.ListBoxOutPut.Items.Add(item["Title"]+ item["ProductProductName"]));
}