repeaterplusnone.cs

本系统是在asp版《在线文件管理器》的基础上设计制作

//------------------------------------------------------------------------------
// <copyright company="Telligent Systems">
//     Copyright (c) Telligent Systems Corporation.  All rights reserved.
// </copyright> 
//------------------------------------------------------------------------------

using System;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace CommunityServer.Controls
{
	/// <summary>
	/// This class is based on the <see cref="Repeater"/> class.  It allows you to define a NoneTemplate that
	/// will be displayed when there are no items found in the data source.
	/// </summary>
	public class RepeaterPlusNone : Repeater
	{

		#region Public Properties

		/// <summary>
		/// The template that is used to define what is displayed when no items are found.
		/// </summary>
		[
		Browsable( false ),
		DefaultValue( null ),
		Description( "Defines the ITemplate to be used when no items are defined in the datasource." ),
		PersistenceMode( PersistenceMode.InnerProperty ),
		]
		public virtual ITemplate NoneTemplate 
		{
			get { return _noneTemplate; }
			set { _noneTemplate = value; }
		}
		private ITemplate _noneTemplate;

		[DefaultValue( true )]
		public virtual bool ShowHeaderFooterOnNone
		{
			get
			{
				Object state = ViewState["ShowHeaderFooterOnNone"];
				if(state != null)
					return (bool)state;
				return true;
			}
			set { ViewState["ShowHeaderFooterOnNone"] = value; }
		}

		#endregion

		#region OnDataBinding

		/// <exclude/>
		protected override void OnDataBinding(EventArgs e)
		{
			base.OnDataBinding(e);
			if((Items.Count == 0) && (NoneTemplate != null))
			{
				this.Controls.Clear();

				if(ShowHeaderFooterOnNone && (this.HeaderTemplate != null))
				{
					RepeaterItem headerItem = this.CreateItem(-1, ListItemType.Header);
					RepeaterItemEventArgs headerArgs = new RepeaterItemEventArgs(headerItem);
					this.InitializeItem(headerItem);
					this.OnItemCreated(headerArgs);
					this.Controls.Add(headerItem);
					headerItem.DataBind();
					this.OnItemDataBound(headerArgs);
				}

				// Process the NoneTemplate
				RepeaterItem noneItem = new RepeaterItem(-1, ListItemType.Item);
				RepeaterItemEventArgs noneArgs = new RepeaterItemEventArgs(noneItem);
				NoneTemplate.InstantiateIn(noneItem);
				this.OnItemCreated(noneArgs);
				this.Controls.Add(noneItem);
				OnNoneItemsDataBound(noneArgs);

				if(ShowHeaderFooterOnNone && (this.FooterTemplate != null))
				{
					RepeaterItem footerItem = this.CreateItem(-1, ListItemType.Footer);
					RepeaterItemEventArgs footerArgs = new RepeaterItemEventArgs(footerItem);
					this.InitializeItem(footerItem);
					this.OnItemCreated(footerArgs);
					this.Controls.Add(footerItem);
					footerItem.DataBind();
					this.OnItemDataBound(footerArgs);
				}

				this.ChildControlsCreated = true;
			}
		}

		#endregion

		#region Event Handlers

		/// <summary>
		/// This event is called when no items were found in the data source.
		/// </summary>
		public event RepeaterItemEventHandler NoneItemsDataBound
		{
			add { base.Events.AddHandler(EventNoneItemsDataBound, value); }
			remove { base.Events.RemoveHandler(EventNoneItemsDataBound, value); }
		}
		private static readonly object EventNoneItemsDataBound = new object();

		/// <summary>
		/// This method is called to invoke the <see cref="NoneItemsDataBound"/> event.
		/// </summary>
		/// <param name="e">The <see cref="RepeaterItemEventArgs"/> to be passed to the event.</param>
		protected virtual void OnNoneItemsDataBound(RepeaterItemEventArgs e)
		{
			RepeaterItemEventHandler handler = (RepeaterItemEventHandler)base.Events[EventNoneItemsDataBound];
			if(handler != null)
				handler(this, e);

		}

		#endregion

	}
}