[SharePoint开发详解] 自定义字段开发: 投票字段

最新推荐文章于 2025-07-02 10:17:45 发布

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最新推荐文章于 2025-07-02 10:17:45 发布

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文章标签： c# javascript ViewUI

原文链接：http://www.cnblogs.com/tonnie/archive/2010/05/10/voting.html

本文详细介绍了如何在SharePoint环境中实现投票功能，并通过定制的自定义字段和应用页面处理投票流程，包括用户投票、结果统计及展示。实现了普通用户友好使用的投票系统，支持List和DocumentLibrary，确保同一用户投票只记录一次。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

需求：

在公司使用SharePoint的过程中，常常有这样的需求，要为一个Document Library或者List中的某一个Item进行打分，投票，根据投票高低来作决策。比如优秀员工的评比，用户可以直接在页面上点击投票按钮，并得到当前的投票状态。

现状：

在CodePlex上找了一个现成的Content type(HighLight)，安装使用后，发现普通用户不太会使用，而且投票页面没有直接的结果显示，不能完全满足用户的需求，所以想自己开发一个custom field，让普通用户可以象添加一般的field一样添加，并且容易使用。

开发：

要实现投票的功能，需要开发2个相关联的custom field。一个负责记录当前所有已投票的用户的信息，这样防止用户多次点击后重复投票，我们称这个field为voting field。另一个field负责计数，显示当前总共的投票数，称为Voting Result field。可能有人要问，为什么不把这两个合而为一呢? 这里主要考虑到排序的问题，因为要记录用户投票信息的字段的type不能是text的，因为text类型有255的长度限制，只能是note型，而note型是不支持在view的页面中排序的。

下面详细介绍具体的开发

1 Voting Field

首先是字段类ItemVoting的代码

代码

  1 public class ItemVoting : SPFieldText
  2     {
  3          private static string [] CustomPropertyNames = new string [] { " FieldNameProperty " };
  4
  5          public ItemVoting(SPFieldCollection fields, string fieldName)
  6             : base (fields, fieldName)
  7         {
  8             InitProperties();
  9              this .ShowInNewForm = true ;
10              this .ShowInEditForm = true ;
11
12         }
13
14          public ItemVoting(SPFieldCollection fields, string typeName, string displayName)
15             : base (fields, typeName, displayName)
16         {
17             InitProperties();
18              this .ShowInNewForm = true ;
19              this .ShowInEditForm = true ;
20         }
21
22          #region Property storage and bug workarounds - do not edit
23
24          /// <summary>
25          /// Indicates that the field is being created rather than edited. This is necessary to
26          /// work around some bugs in field creation.
27          /// </summary>
28          public bool IsNew
29         {
30              get { return _IsNew; }
31              set { _IsNew = value; }
32         }
33          private bool _IsNew = false ;
34
35          /// <summary>
36          /// Backing fields for custom properties. Using a dictionary to make it easier to abstract
37          /// details of working around SharePoint bugs.
38          /// </summary>
39          private Dictionary < string , string > CustomProperties = new Dictionary < string , string > ();
40
41          /// <summary>
42          /// Static store to transfer custom properties between instances. This is needed to allow
43          /// correct saving of custom properties when a field is created - the custom property
44          /// implementation is not used by any out of box SharePoint features so is really buggy.
45          /// </summary>
46          private static Dictionary < string , string > CustomPropertiesForNewFields = new Dictionary < string , string > ();
47
48          /// <summary>
49          /// Initialise backing fields from base property store
50          /// </summary>
51          private void InitProperties()
52         {
53              foreach ( string propertyName in CustomPropertyNames)
54             {
55                 CustomProperties[propertyName] = base .GetCustomProperty(propertyName) + "" ;
56             }
57         }
58
59          /// <summary>
60          /// Take properties from either the backing fields or the static store and
61          /// put them in the base property store
62          /// </summary>
63          private void SaveProperties()
64         {
65              foreach ( string propertyName in CustomPropertyNames)
66             {
67                  base .SetCustomProperty(propertyName, GetCustomProperty(propertyName));
68             }
69         }
70
71          /// <summary>
72          /// Get an identifier for the field being added/edited that will be unique even if
73          /// another user is editing a property of the same name.
74          /// </summary>
75          /// <param name="propertyName"></param>
76          /// <returns></returns>
77          private string GetCacheKey( string propertyName)
78         {
79              return SPContext.Current.GetHashCode() + " _ " + (ParentList == null ? " SITE " : ParentList.ID.ToString()) + " _ " + propertyName;
80         }
81
82          /// <summary>
83          /// Replace the buggy base implementation of SetCustomProperty
84          /// </summary>
85          /// <param name="propertyName"></param>
86          /// <param name="propertyValue"></param>
87          new public void SetCustomProperty( string propertyName, object propertyValue)
88         {
89              if (IsNew)
90             {
91                  // field is being added - need to put property in cache
92                 CustomPropertiesForNewFields[GetCacheKey(propertyName)] = propertyValue + "" ;
93             }
94
95             CustomProperties[propertyName] = propertyValue + "" ;
96         }
97
98          /// <summary>
99          /// Replace the buggy base implementation of GetCustomProperty
100          /// </summary>
101          /// <param name="propertyName"></param>
102          /// <param name="propertyValue"></param>
103          new public object GetCustomProperty( string propertyName)
104         {
105              if ( ! IsNew && CustomPropertiesForNewFields.ContainsKey(GetCacheKey(propertyName)))
106             {
107                  string s = CustomPropertiesForNewFields[GetCacheKey(propertyName)];
108                 CustomPropertiesForNewFields.Remove(GetCacheKey(propertyName));
109                 CustomProperties[propertyName] = s;
110                  return s;
111             }
112              else
113             {
114                  return CustomProperties[propertyName];
115             }
116         }
117
118          /// <summary>
119          /// Called when a field is created. Without this, update is not called and custom properties
120          /// are not saved.
121          /// </summary>
122          /// <param name="op"></param>
123          public override void OnAdded(SPAddFieldOptions op)
124         {
125              base .OnAdded(op);
126             Update();
127         }
128
129          #endregion
130
131
132          public override BaseFieldControl FieldRenderingControl
133         {
134              get
135             {
136                 BaseFieldControl fieldControl = new ItemVotingControl( this );
137                 fieldControl.FieldName = InternalName;
138                  if (String.IsNullOrEmpty(fieldControl.ItemFieldValue as string ))
139                 {
140                     fieldControl.ItemFieldValue = " <Root><Item><CurrentFieldName Type=\ " String\ " >[ " + fieldControl.FieldName + " ]</CurrentFieldName><Account Type=\ " String\ " >ads\\mossadmin</Account></Item></Root> " ;
141                 }
142                  return fieldControl;
143             }
144         }
145
146          public override void Update()
147         {
148             SaveProperties();
149              base .Update();
150         }
151
152          public string FieldNameProperty
153         {
154              get { return this .GetCustomProperty( " HiddenFieldName " ) + "" ; }
155              set { this .SetCustomProperty( " HiddenFieldName " , value); }
156         }
157
158
159
160     }

为了能够在view页面得到当前字段的internal name(需要提供给投票处理页面voting.aspx)，我们为字段赋的初始值中包含了当前field的internal name（ fieldControl.ItemFieldValue = "<Root><Item><CurrentFieldName Type=\"String\">[" + fieldControl.FieldName + "]</CurrentFieldName><Account Type=\"String\">ads\\mossadmin</Account></Item></Root>";），为了在页面中，能够使得我们开发的2个自定义字段发生联系，我们在自定义字段的xml文件中为这个字段中添加了一个field property-- HiddenFieldName

接下来是呈现类代码：

代码

public class ItemVotingControl : BaseFieldControl
    {
         private ItemVoting field;
         private List < Voter > voterList;
         private LiteralControl ltcNumber;
         private bool isVoted = false ;
         public ItemVotingControl(ItemVoting parentField)
        {
             this .field = parentField;
        }

         protected override void OnInit(EventArgs e)
        {
             base .OnInit(e);
             if ( this .ListItemFieldValue != null )
            {
                 this .voterList = SerializeUtility.Deserialize( this .ListItemFieldValue.ToString());
            }
             else
            {
                 this .voterList = new List < Voter > ();
            }
        }

         protected override void CreateChildControls()
        {
            ltcNumber = new LiteralControl();
             this .Controls.Add(ltcNumber);
        }

         public override void UpdateFieldValueInItem()
        {

        }

         protected override void RenderFieldForDisplay(HtmlTextWriter output)
        {
             int countValue = voterList.Count > 0 ? voterList.Count - 1 : voterList.Count;
            output.Write(countValue.ToString());
        }

         protected override void Render(HtmlTextWriter output)
        {
            RenderFieldForDisplay(output);
        }
    }

呈现控件取出了序列化后的投票结果，并反序列化，然后显示. 注意这里的显示只是指在New.aspx,edit.aspx,display.aspx这三个页面的显示，当然用户要求直接在view的页面上投票，所以我们要提供字段在view页面的现示实现。于是我们修改了field_字段.xml文件中的<RenderPattern Name="DisplayPattern">节。

下面是完整的field_字段.xml 文件:

代码

1 <? xml version="1.0" encoding="utf-8" ?>
2 < FieldTypes >
3    < FieldType >
4      < Field Name ="TypeName" > ItemVoting </ Field >
5      < Field Name ="ParentType" > Note </ Field >
6      < Field Name ="TypeDisplayName" > Item Voting </ Field >
7      < Field Name ="TypeShortDescription" > Item Voting </ Field >
8      < Field Name ="UserCreatable" > TRUE </ Field >
9      < Field Name ="Sortable" > TRUE </ Field >
10      < Field Name ="AllowBaseTypeRendering" > TRUE </ Field >
11      < Field Name ="Filterable" > TRUE </ Field >
12      < Field Name ="FieldTypeClass" > AECSharePoint.Field.Voting.ItemVoting, AECSharePoint.Field.Voting, Version=1.0.0.0, Culture=neutral, PublicKeyToken=c8afc6fd77dac842 </ Field >
13      < PropertySchema >
14        < Fields >
15          < Field Hidden ="FALSE" Name ="HiddenFieldName"
16         DisplayName ="My Custom Property"
17         Type ="Text" >
18          </ Field >
19        </ Fields >
20        < Fields ></ Fields >
21      </ PropertySchema >
22      < RenderPattern Name ="DisplayPattern" >
23        < HTML >
24          <![CDATA[
25         <a id='linkVoting' href="javascript:window.location= SetLocation(' ]]> </ HTML >
26        < ListProperty Select ="Name" />
27        < HTML >
28          <![CDATA[ ',' ]]>
29        </ HTML >
30        < ListProperty Select ="Title" />
31        < HTML >
32          <![CDATA[ ',' ]]>
33        </ HTML >
34        < Column Name ="ID" />
35        < HTML >
36          <![CDATA[ ',' ]]>
37        </ HTML >
38          < ListProperty Select ="DefaultViewUrl" />
39        < HTML >
40          <![CDATA[ ',' ]]>
41        </ HTML >
42        < Column HTMLEncode ="TRUE" />
43        < HTML >
44          <![CDATA[ ');"><img onerror="SetLinkDisplayContent(' ]]>
45        </ HTML >
46        < Column HTMLEncode ="TRUE" />
47        < HTML >
48          <![CDATA[ ',this);" border=0 src="#"><div align="center" id="divCount" style="clear:left;display:inline;"></div></a> ]]>
49        </ HTML >
50        < HTML >
51          <![CDATA[
52         <script>
53         function SetLocation(listName,listTitle, itemID, listViewUrl, fieldValue)
54         {
55             var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
56             xmlDoc.loadXML(fieldValue);
57             var fieldNameNode = xmlDoc.documentElement.selectSingleNode("//Item/CurrentFieldName");
58             var fieldName = fieldNameNode.text;
59             var start = fieldName.indexOf("[");
60             var end = fieldName.indexOf("]");
61
62             fieldName = fieldName.substring(start+1, end);
63
64             var queryStr = "?listName=" + listName + "&itemID=" + itemID + "&fieldName=" + fieldName + "&Source=" + window.location;
65             var currentSiteURL = "http://" + document.location.host;
66
67             var endIndex = listViewUrl.indexOf("/Lists/");
68             if(endIndex == -1)
69             {
70                 endIndex = listViewUrl.indexOf("/" + listTitle + "/")
71             }
72             var subUrl = listViewUrl.substring(0,endIndex);
73             subUrl += "/_layouts/AECSharePoint/Voting.aspx";
74             currentSiteURL += subUrl + queryStr;
75             return currentSiteURL;
76         }
77
78         function SetLinkDisplayContent(fieldValue,o)
79         {
80
81             o.src = "/_layouts/AECSharePoint/voting.gif";
82         }
83
84         </script>
85          ]]>
86        </ HTML >
87      </ RenderPattern >
88    </ FieldType >
89 </ FieldTypes >
90
91

在 <RenderPattern Name="DisplayPattern"> 中我们使得字段在view页面显示为一个图标，点击图标后跳转到我们开发的一个application page，同时为这个page传输必要的listid，itemid等信息，此页面处理此次投票，保存投票结果作为字段的值。

下面是我们放在Template/Layout/下的自定义application page，也就是上面xml中提到的voting.aspx 代码：

代码

<% @ Assembly Name = " Microsoft.SharePoint.ApplicationPages, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c " %>
<% @ Page Language = " C# " Inherits = " Microsoft.SharePoint.WebControls.LayoutsPageBase " MasterPageFile = " ~/_layouts/application.master " %>
<% @ Import Namespace = " Microsoft.SharePoint " %>
<% @ Import Namespace = " Microsoft.SharePoint.WebControls " %>
<% @ Import Namespace = " System.Xml " %>
<% @ Import Namespace = " System.Reflection " %>
<% @ Import Namespace = " System.Collections.Generic " %>
<% @ Import Namespace = " System.Diagnostics " %>

< script runat = " server " >
     public Dictionary < string , object > initialParam = null ;
     private List < Voter > voterList;
     private bool isVoted = false ;
     class Voter
    {
         private string _currentFieldName;
         private string _account;

         public string CurrentFieldName
        {
             get
            {
                 return this ._currentFieldName;
            }
             set
            {
                 this ._currentFieldName = value;
            }
        }

         public string Account
        {
             get
            {
                 return this ._account;
            }
             set
            {
                 this ._account = value;
            }
        }
    }

     #region // Serialize&deserialize the voting result
     class SerializeUtility
    {
         public static string Serialize(List < Voter > GenericList)
        {
            XmlDocument result = new XmlDocument();
            result.LoadXml( " <Root></Root> " );
             foreach (Voter obj in GenericList)
            {
                XmlElement Item = result.CreateElement( " Item " );
                PropertyInfo[] properties = obj.GetType().GetProperties();
                 foreach (PropertyInfo property in properties)
                {
                     if (property.GetValue(obj, null ) != null )
                    {
                        XmlElement element = result.CreateElement(property.Name);
                        element.SetAttribute( " Type " , property.PropertyType.Name);
                        element.InnerText = property.GetValue(obj, null ).ToString();
                        Item.AppendChild(element);
                    }
                }
                result.DocumentElement.AppendChild(Item);
            }
             return result.InnerXml;
        }

         public static List < Voter > Deserialize( string XmlStr)
        {
            List < Voter > result = new List < Voter > ();
            XmlDocument XmlDoc = new XmlDocument();
            XmlDoc.LoadXml(XmlStr);
             foreach (XmlNode ItemNode in XmlDoc.GetElementsByTagName( " Root " ).Item( 0 ).ChildNodes)
            {
                Voter item = Activator.CreateInstance < Voter > ();
                PropertyInfo[] properties = typeof (Voter).GetProperties();
                 foreach (XmlNode propertyNode in ItemNode.ChildNodes)
                {
                     string name = propertyNode.Name;
                     string type = propertyNode.Attributes[ " Type " ].Value;
                     string value = propertyNode.InnerXml;
                     foreach (PropertyInfo property in properties)
                    {
                         if (name == property.Name)
                        {
                            property.SetValue(item, Convert.ChangeType(value, property.PropertyType), null );
                        }
                    }
                }
                result.Add(item);
            }
             return result;
        }
    }
     #endregion

     class VotingBiz
    {
         internal Voter GetCurrentVoter( string fieldName, string account)
        {
            Voter currentVoter = new Voter();
            currentVoter.Account = account;
            currentVoter.CurrentFieldName = string .Empty;
             return currentVoter;
        }

         internal void UpdateListFieldValueWithElevatedPrivileges(Guid listID, int itemID, Dictionary < string , object > dicFieldValue)
        {
             if (SPContext.Current == null )
                 return ;
            SPSecurity.RunWithElevatedPrivileges( delegate ()
            {
                 using (SPSite site = new SPSite(SPContext.Current.Site.ID))
                {
                     using (SPWeb web = site.OpenWeb(SPContext.Current.Web.ID))
                    {
                        web.AllowUnsafeUpdates = true ;
                        SPList list = web.Lists[listID];
                        SPListItem item = list.GetItemById(itemID);
                         if (item == null )
                        {
                             return ;
                        }
                         else
                        {
                             foreach (KeyValuePair < string , object > singleItem in dicFieldValue)
                            {
                                item[singleItem.Key] = singleItem.Value;
                            }
                            item.SystemUpdate( false );
                        }
                    }
                }

            });
        }

         internal bool CheckIsItemVoted( object itemValue, string fieldName, string account)
        {
            VotingBiz voteMgnt = new VotingBiz();
            List < Voter > voterList = null ;
            Voter currentVoter = voteMgnt.GetCurrentVoter(fieldName, account);
             if (itemValue == null )
            {
                 return false ;
            }
             else
            {
                voterList = SerializeUtility.Deserialize(itemValue.ToString());
                 // if (itemValue.ToString().IndexOf(currentVoter.Account) != -1)
                 // {
                 //     return true;
                 // }
                 // else
                 // {
                 //     return false;
                 // }
                 if ( ! voterList.Exists( delegate (Voter v) { return v.Account == currentVoter.Account; }))
                {
                     return false ;
                }
                 else
                {
                     return true ;
                }
            }
             // if (!voterList.Exists(delegate(Voter v) { return v.Account == currentVoter.Account; }))
             // {
             //     return false;
             // }
             // else
             // {
             //     return true;
             // }
        }
    }

     protected override void OnLoad(EventArgs e)
    {
        InitialParamter();
    }
     protected void InitialParamter()
    {
         try
        {
            initialParam = new Dictionary < string , object > ();
            initialParam.Add( " listName " , Request.QueryString[ " listName " ].ToString());
            initialParam[ " itemID " ] = Request.QueryString[ " itemID " ].ToString();
            initialParam[ " fieldName " ] = Request.QueryString[ " fieldName " ].ToString();
            initialParam[ " fieldValue " ] = GetItemValue(initialParam[ " fieldName " ] as string , initialParam[ " listName " ] as string , Int32.Parse(initialParam[ " itemID " ] as string ));
        }
         catch (Exception ex)
        {
            EventLog.WriteEntry( " Voting Field " , SPContext.Current.Web.Title + " : " + ex.Message + " -- " + ex.StackTrace);
            Response.Write( " Error happend, please contact site admin " );
        }
    }

     protected object GetItemValue( string fieldName, string listName, int itemId)
    {
         using (SPSite site = new SPSite(SPContext.Current.Site.ID))
        {
             using (SPWeb web = site.OpenWeb(SPContext.Current.Web.ID))
            {
                Guid listId = new Guid(listName);
                SPList list = web.Lists[listId];
                SPListItem item = list.GetItemById(itemId);
                 return item[fieldName];
            }
        }
    }

     private string GetVotingResultFieldName(Guid listId)
    {
         if (SPContext.Current == null )
             return null ;

         string votingFieldName = String.Empty;
         using (SPSite site = new SPSite(SPContext.Current.Site.ID))
        {
             using (SPWeb web = site.OpenWeb(SPContext.Current.Web.ID))
            {
                SPList list = web.Lists[listId];
                 foreach (SPField field in list.Fields)
                {
                     if ( null != field.GetCustomProperty( " FlagFieldNameProperty " ))
                    {
                        votingFieldName = field.InternalName;
                         break ;
                    }
                }

            }
        }
         return votingFieldName;
    }



     protected void btnVote_Click( object sender, EventArgs e)
    {
        VotingBiz voteMgnt = new VotingBiz();

         if ( null != initialParam)
        {
             if ( ! voteMgnt.CheckIsItemVoted(initialParam[ " fieldValue " ], initialParam[ " fieldName " ] as string , SPContext.Current.Web.CurrentUser.ID.ToString()))
            {
                Voter currentVoter = voteMgnt.GetCurrentVoter(initialParam[ " fieldName " ] as string , SPContext.Current.Web.CurrentUser.ID.ToString());
                 if (initialParam[ " fieldValue " ] != null )
                {
                     this .voterList = SerializeUtility.Deserialize(initialParam[ " fieldValue " ] as string );
                }
                voterList.Add(currentVoter);
                Guid listId = new Guid(initialParam[ " listName " ] as string );
                 int itemId = Int32.Parse(initialParam[ " itemID " ] as string );
                 string fieldName = initialParam[ " fieldName " ] as string ;
                 string votingResultFieldName = GetVotingResultFieldName(listId);
                Dictionary < string , object > fieldNameValuePairs = new Dictionary < string , object > ();
                fieldNameValuePairs[fieldName] = SerializeUtility.Serialize(voterList);
                 if ( ! String.IsNullOrEmpty(votingResultFieldName))
                {
                    fieldNameValuePairs[votingResultFieldName] = voterList.Count - 1 ;
                }
                voteMgnt.UpdateListFieldValueWithElevatedPrivileges(listId, itemId, fieldNameValuePairs);
                 this .isVoted = true ;
            }
        }

        ReturnToSourcePage();

    }

     private void ReturnToSourcePage()
    {
         string sourceUrl = Request.QueryString[ " Source " ].ToString();
        Response.Redirect(sourceUrl);
    }

     protected void btnBack_Click( object sender, EventArgs e)
    {
        ReturnToSourcePage();
    }
</ script >

< asp:Content ID = " Content1 " ContentPlaceHolderID = " PlaceHolderPageTitleInTitleArea " runat = " server " >
     < h >
        Vote Here
     </ h >

</ asp:Content >
< asp:Content ID = " Content2 " ContentPlaceHolderID = " PlaceHolderMain " runat = " server " >
     < div >
        Are you sure to vote this item ? < br />
     < b > Please note that your vote would be counted only once even if you vote again !</ b >
     < br />
     < br />
         < asp:Button ID = " btnVote " runat = " server " Text = " Vote " OnClick = " btnVote_Click " class = " ms-ButtonHeightWidth " Width = " 80px " />
         < asp:Button ID = " btnBack " runat = " server " Text = " Cancel " OnClick = " btnBack_Click " class = " ms-ButtonHeightWidth " Width = " 80px " />
     </ div >
</ asp:Content >

下面介绍统计投票的字段voting result field

1.字段类代码

代码

  1 public class ItemVotingResult : SPFieldText
  2     {
  3          private static string [] CustomPropertyNames = new string [] { " MyCustomProperty " };
  4
  5          public ItemVotingResult(SPFieldCollection fields, string fieldName)
  6             : base (fields, fieldName)
  7         {
  8             InitProperties();
  9         }
10
11          public ItemVotingResult(SPFieldCollection fields, string typeName, string displayName)
12             : base (fields, typeName, displayName)
13         {
14             InitProperties();
15         }
16
17          #region Property storage and bug workarounds - do not edit
18
19          /// <summary>
20          /// Indicates that the field is being created rather than edited. This is necessary to
21          /// work around some bugs in field creation.
22          /// </summary>
23          public bool IsNew
24         {
25              get { return _IsNew; }
26              set { _IsNew = value; }
27         }
28          private bool _IsNew = false ;
29
30          /// <summary>
31          /// Backing fields for custom properties. Using a dictionary to make it easier to abstract
32          /// details of working around SharePoint bugs.
33          /// </summary>
34          private Dictionary < string , string > CustomProperties = new Dictionary < string , string > ();
35
36          /// <summary>
37          /// Static store to transfer custom properties between instances. This is needed to allow
38          /// correct saving of custom properties when a field is created - the custom property
39          /// implementation is not used by any out of box SharePoint features so is really buggy.
40          /// </summary>
41          private static Dictionary < string , string > CustomPropertiesForNewFields = new Dictionary < string , string > ();
42
43          /// <summary>
44          /// Initialise backing fields from base property store
45          /// </summary>
46          private void InitProperties()
47         {
48              foreach ( string propertyName in CustomPropertyNames)
49             {
50                 CustomProperties[propertyName] = base .GetCustomProperty(propertyName) + "" ;
51             }
52         }
53
54          /// <summary>
55          /// Take properties from either the backing fields or the static store and
56          /// put them in the base property store
57          /// </summary>
58          private void SaveProperties()
59         {
60              foreach ( string propertyName in CustomPropertyNames)
61             {
62                  base .SetCustomProperty(propertyName, GetCustomProperty(propertyName));
63             }
64         }
65
66          /// <summary>
67          /// Get an identifier for the field being added/edited that will be unique even if
68          /// another user is editing a property of the same name.
69          /// </summary>
70          /// <param name="propertyName"></param>
71          /// <returns></returns>
72          private string GetCacheKey( string propertyName)
73         {
74              return SPContext.Current.GetHashCode() + " _ " + (ParentList == null ? " SITE " : ParentList.ID.ToString()) + " _ " + propertyName;
75         }
76
77          /// <summary>
78          /// Replace the buggy base implementation of SetCustomProperty
79          /// </summary>
80          /// <param name="propertyName"></param>
81          /// <param name="propertyValue"></param>
82          new public void SetCustomProperty( string propertyName, object propertyValue)
83         {
84              if (IsNew)
85             {
86                  // field is being added - need to put property in cache
87                 CustomPropertiesForNewFields[GetCacheKey(propertyName)] = propertyValue + "" ;
88             }
89
90             CustomProperties[propertyName] = propertyValue + "" ;
91         }
92
93          /// <summary>
94          /// Replace the buggy base implementation of GetCustomProperty
95          /// </summary>
96          /// <param name="propertyName"></param>
97          /// <param name="propertyValue"></param>
98          new public object GetCustomProperty( string propertyName)
99         {
100              if ( ! IsNew && CustomPropertiesForNewFields.ContainsKey(GetCacheKey(propertyName)))
101             {
102                  string s = CustomPropertiesForNewFields[GetCacheKey(propertyName)];
103                 CustomPropertiesForNewFields.Remove(GetCacheKey(propertyName));
104                 CustomProperties[propertyName] = s;
105                  return s;
106             }
107              else
108             {
109                  return CustomProperties[propertyName];
110             }
111         }
112
113          /// <summary>
114          /// Called when a field is created. Without this, update is not called and custom properties
115          /// are not saved.
116          /// </summary>
117          /// <param name="op"></param>
118          public override void OnAdded(SPAddFieldOptions op)
119         {
120              base .OnAdded(op);
121             Update();
122         }
123
124          #endregion
125
126
127          public override BaseFieldControl FieldRenderingControl
128         {
129              get
130             {
131                 BaseFieldControl fieldControl = new ItemVotingResultControl( this );
132
133                 fieldControl.FieldName = InternalName;
134
135                  return fieldControl;
136             }
137         }
138
139          public override void Update()
140         {
141             SaveProperties();
142              base .Update();
143         }
144
145          public string MyCustomProperty
146         {
147              get { return this .GetCustomProperty( " FlagFieldNameProperty " ) + "" ; }
148              set { this .SetCustomProperty( " FlagFieldNameProperty " , value); }
149         }
150
151     }

为了能够在投票处理页面voting.aspx中找到此字段，并将结果保存到此字段，我们加了field property--FlagFieldNameProperty

2 字段显示类

代码

public class ItemVotingResultControl : BaseFieldControl
    {
         private ItemVotingResult field;
         private LiteralControl lcResult = null ;

         public ItemVotingResultControl(ItemVotingResult parentField)
        {
             this .field = parentField;

        }

         protected override void OnInit(EventArgs e)
        {
             base .OnInit(e);
        }



         protected override void CreateChildControls()
        {
             base .CreateChildControls();
            lcResult = new LiteralControl();
             object currentResult = GetItemVotingResult();
             if ( null != currentResult)
            {
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.LoadXml(currentResult.ToString());

                lcResult.Text = (xmlDoc.DocumentElement.ChildNodes.Count - 1 ) + "" ;
            }
             else
            {
                lcResult.Text = " 0 " ;
            }
        }

         public override void UpdateFieldValueInItem()
        {

        }

         protected override void Render(HtmlTextWriter output)
        {
            lcResult.RenderControl(output);
        }
    }

3 field_VotingResult.xml

代码

<? xml version = " 1.0 " encoding = " utf-8 " ?>
< FieldTypes >
   < FieldType >
     < Field Name = " TypeName " > ItemVotingResult </ Field >
     < Field Name = " ParentType " > Text </ Field >
     < Field Name = " TypeDisplayName " > Item Voting Result </ Field >
     < Field Name = " TypeShortDescription " > Item Voting Result </ Field >
     < Field Name = " UserCreatable " > TRUE </ Field >
     < Field Name = " Sortable " > TRUE </ Field >
     < Field Name = " AllowBaseTypeRendering " > TRUE </ Field >
     < Field Name = " Filterable " > TRUE </ Field >
     < Field Name = " FieldTypeClass " > AECSharePoint.Field.VotingResult.ItemVotingResult, AECSharePoint.Field.VotingResult, Version = 1.0 . 0.0 , Culture = neutral, PublicKeyToken = 09a5c45e643a0621 </ Field >

     < PropertySchema >
       < Fields >
         < Field Hidden = " FALSE " Name = " FlagFieldNameProperty "
        DisplayName = " My Custom Property "
        Type = " Text " >
         </ Field >
       </ Fields >
       < Fields ></ Fields >
     </ PropertySchema >
     < RenderPattern Name = " DisplayPattern " >
       < Column />
     </ RenderPattern >
   </ FieldType >
</ FieldTypes >

这个字段主要用来现示投票结果，比较简单。

主要效果图：

投票页面：