Sharepoint 2010 控件系统 之 扩展 SaveButton

        上一篇介绍了Sharepoint控件的基本应用，这一篇介绍一下SaveButton的扩展，在扩展之前讲个案例，通过两个字段验证唯一性，这样在开发时就要用到扩展了，但用EventReceive也可以，哪个更好就自己体会吧。

        SaveButton目前不支付保存前事件和保存后事件，但是在开发项目时，保存前总要用到验证，因此为了更好的满足要求，合理规划代码就有了扩展这一篇文章，对SaveButton扩展了两个事件，保存前BeforeSaveItem，保存后AfterSaveItem，这两个事件在实际应用中应用比较多。

       首先声明事件和委托，如果对事件和委托不清楚可以Google一下，分页就是最好的事例。

/// <summary>
    /// 保存前
    /// </summary>
    public class BeforeSaveItemArgs : EventArgs
    {
        /// <summary>当前列表的ListItem</summary>
        public SPListItem ListItem { get; set; }
        /// <summary>默认True，如果是False，则验证通不过，不能保存</summary>
        public bool Validate { get; set; }
        /// <summary>当前列表的 List</summary>
        public SPList List { get; set; }
        public Dictionary<string, string> Parameters { get; set; }
    }

    /// <summary>
    /// 保存后
    /// </summary>
    public class AfterSaveItemArgs : EventArgs
    {
        /// <summary>当前列表的 List</summary>
        public SPList List { get; set; }
        /// <summary>当前列表的ListItem</summary>
        public SPListItem ListItem { get; set; }
        /// <summary>判断是否保存成功</summary>
        public bool Success { get; set; }
        public Dictionary<string, string> Parameters { get; set; }
    }

    /// <summary>
    /// 声明委托 保存前事件
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    public delegate void BeforeSaveItemHandler(object sender, BeforeSaveItemArgs e);
    /// <summary>
    /// 声明委托 保存后事件
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    public delegate void AfterSaveItemHandler(object sender, AfterSaveItemArgs e);

继承SaveButton ，Override SaveItem ，下面为所有的代码

public class TSaveButton : SaveButton
    {
        private static readonly object EventBeforeSaveItem = new object();
        private static readonly object EventAfterSaveItem = new object();

        #region Event
        /// <summary>
        /// 定义保存前事件
        /// </summary>
        public event BeforeSaveItemHandler BeforeSaveItem
        {
            add
            {
                base.Events.AddHandler(EventBeforeSaveItem, value);
            }
            remove
            {
                base.Events.RemoveHandler(EventBeforeSaveItem, value);
            }
        }
        /// <summary>
        /// 定义保存后事件
        /// </summary>
        public event AfterSaveItemHandler AfterSaveItem
        {
            add
            {
                base.Events.AddHandler(EventAfterSaveItem, value);
            }
            remove
            {
                base.Events.RemoveHandler(EventAfterSaveItem, value);
            }
        }
        #endregion

        protected virtual void SaveIteming(BeforeSaveItemArgs e)
        {
            BeforeSaveItemHandler handler = (BeforeSaveItemHandler)base.Events[EventBeforeSaveItem];
            if (handler != null)
            {
                handler(this, e);
            }
        }

        protected virtual void SaveItemed(AfterSaveItemArgs e)
        {
            AfterSaveItemHandler handler = (AfterSaveItemHandler)base.Events[EventAfterSaveItem];
            if (handler != null)
            {
                handler(this, e);
            }
        }

        /// <summary>
        /// Override SaveItem
        /// </summary>
        /// <returns></returns>
        protected override bool SaveItem()
        {

            SPListItem item = base.ItemContext.ListItem; //获取当前Items

            BeforeSaveItemArgs beforeSaveArgs =
                new BeforeSaveItemArgs() { ListItem = item, Validate = true, List = base.List }; //构造默认值
            SaveIteming(beforeSaveArgs);
            if (beforeSaveArgs.Validate) //验证保存是否成功
            {
                bool result = base.SaveItem(); //保存成功返回True
                AfterSaveItemArgs afterSaveArgs =
                    new AfterSaveItemArgs() { ListItem = item, Success = result,List = base.List};
                SaveItemed(afterSaveArgs);
                return result;
            }
            else
                return false;
        }
    }

扩展完成之后，就是如何运用了，在上一篇中已经提到了这两个事件 OnBeforeSaveItem OnAfterSaveItem

<T:TSaveButton runat="server" ID="btnSave" OnInit="OnInitSave" OnBeforeSaveItem="BeforeSaveItem" OnAfterSaveItem="AfterSaveItem" />

现在事件已经注册好了，接下来就是写 BeforeSaveItem的方法

#region OnBeforeSaveItem
        public void BeforeSaveItem(object sender, EventArgs e)
        {
            BeforeSaveItemArgs beforeSaveItemArgs = e as BeforeSaveItemArgs;
            if (beforeSaveItemArgs != null)
            {
                beforeSaveItemArgs.Validate = false;
                if (ValidateCode(beforeSaveItemArgs.ListItem.ID, beforeSaveItemArgs.ListItem.Title, txtCodeKey.Text, beforeSaveItemArgs.List))
                {
                    beforeSaveItemArgs.ListItem["ParentId"] = hfParentId.Value;
                    beforeSaveItemArgs.Validate = true;
                }
                else
                {
                    Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "ModalHostScript", "alert('代码已存在！');", true);
                    return;
                }
                beforeSaveItemArgs.Validate = false;
                if (ValidateCodeName(beforeSaveItemArgs.ListItem.ID, txtCodeName.Text, txtCodeKey.Text, beforeSaveItemArgs.List))
                {
                    beforeSaveItemArgs.Validate = true;
                }
                else
                {
                    Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "ModalHostScript", "alert('名称已存在！');", true);
                }
            }
        }
        #endregion

就这样完成了SaveButton的扩展。如果有其它特殊要求就自己扩展吧。

 参考文章：http://www.cnblogs.com/myheaven/archive/2011/04/29/2032892.html