moss文档浏览次数统计之兄弟篇－－哈哈，列表项的浏览次数统计

看到这篇文章 moss文档浏览次数统计 ，忍不住想到了这篇文章： WSS列表访问统计的实现 －－编写一个custom field,在render的时候读取字段值并判断加1写回，当然如果需要你也可以做成针对每个用户的统计以及防刷新等。

但里面的代码有bug－－权限提升有问题，对ListItem没修改权限的用户访问会出错。
修改后的完整代码如下：
ItemViewCounterField.cs：

public class ItemViewCounterField : SPField
    {
       public ItemViewCounterField(SPFieldCollection fields, string fieldName)
            : base( fields , fieldName )
        {
            Init();
        }

        public ItemViewCounterField(SPFieldCollection fields, string typeName, string displayName)
            : base(fields, typeName, displayName)
        {
            Init();
        }

        void Init()
        {
            //this.ReadOnlyField
            this.ShowInDisplayForm = true;
            this.ShowInEditForm = false;
            this.ShowInNewForm = false;            
        }

        public override BaseFieldControl FieldRenderingControl
        {
            get
            {
                BaseFieldControl ctl = new ItemViewCounterFieldControl();
                ctl.FieldName = this.InternalName;
                return ctl ;
            }
        }
    }

ItemViewCounterFieldControl.cs：

class ItemViewCounterFieldControl : BaseFieldControl
    {
        /**//// <summary>
        /// 更新字段
        /// </summary>
        void UpdateWithElevatedPrivileges()
        {
             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[ this.ListId ];

                            SPListItem item = list.GetItemById(this.ItemId);

                            if (item == null) return;

                            item[this.FieldName] = this.ItemFieldValue;

                            item.SystemUpdate();
                        }
                    }
                }
                );
        }

        protected override void Render(HtmlTextWriter output)
        {
            int cCounter;

            if (this.ItemFieldValue == null)
            {
                cCounter = 1;
            }
            else
            {
                cCounter = Convert.ToInt32(this.ItemFieldValue);
                cCounter++;
            }

            this.ItemFieldValue = cCounter.ToString();

            this.UpdateWithElevatedPrivileges();

            if (this.ItemFieldValue == null)
                output.Write("0");
            else
                output.Write(this.ItemFieldValue.ToString());

        }
 
    }

fldtypes_itemViewCounter.xml
<?xml version="1.0" encoding="utf-8"?>
<!--

-->
<FieldTypes>
    <FieldType>
        <Field Name="TypeName">ItemViewCounter</Field>
        <Field Name="ParentType">Text</Field>
        <Field Name="TypeDisplayName">ItemViewCounter</Field>
        <Field Name="TypeShortDescription">ItemViewCounter</Field>
        <Field Name="UserCreatable">TRUE</Field>
        <Field Name="ShowOnListCreate">TRUE</Field>
        <Field Name="ShowOnDocumentLibraryCreate">TRUE</Field>
        <Field Name="ShowOnSurveyCreate">TRUE</Field>
        <Field Name="ShowOnColumnTemplateCreate">TRUE</Field>
        <Field Name="FieldEditorUserControl"></Field>
        <Field Name="Sortable">TRUE</Field>
        <Field Name="Filterable">FALSE</Field>
        <Field Name="FieldTypeClass"> Here is type full name </Field>
        <PropertySchema>
            <Fields>
            </Fields>
        </PropertySchema>

        <RenderPattern Name="DisplayPattern">
            <Column/>
        </RenderPattern>
        <!--RenderPattern Name="HeaderPattern">
    <RenderPattern Name="DisplayPattern">
        
        <RenderPattern Name="PreviewDisplayPattern"></RenderPattern>
        <RenderPattern Name="PreviewEditPattern"><Property Select="DisplayName" HTMLEncode="TRUE"/></RenderPattern>
        <RenderPattern Name="PreviewNewPattern"><Property Select="DisplayName" HTMLEncode="TRUE"/></RenderPattern-->

    </FieldType>

</FieldTypes>