inputfile.cs

ASP中web自定义控件的使用源码及说明文档

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

namespace Bestcomy.Web.UI.WebControls
{
	/// <summary>
	/// Summary description for InputFile.
	/// </summary>
	[ToolboxData("<{0}:InputFile runat=server></{0}:InputFile>"),Designer(typeof(InputFileDesigner))]
	public class InputFile : WebControl, INamingContainer
	{

		/// <summary>
		/// Gets or sets the text of browse button.
		/// </summary>
		public string Label
		{
			get
			{
				if(ViewState["inputfile_label"]==null)
					ViewState["inputfile_label"] = "选择文件";
				return (string)ViewState["inputfile_label"];
			}
			set
			{
				ViewState["inputfile_label"] = value;
			}
		}

		/// <summary>
		/// Gets or sets size of InputFile.
		/// </summary>
		[DefaultValue("")]
		public int Size
		{
			set
			{
				if(value<1)
					throw new ArgumentOutOfRangeException("value");
				ViewState["InputFile_size"] = value;
			}
			get
			{
				if(ViewState["InputFile_size"]==null)
					return -1;
				return Convert.ToInt16(ViewState["InputFile_size"]);
			}
		}
		
		[DefaultValue(""),Browsable(false)]
		public HttpPostedFile PostedFile
		{
			get
				{
					return this.Context.Request.Files[this.UniqueID];
				}
		}

		public InputFile() : base("BESTCOMY:INPUTFILE")
		{
		}

		protected override void AddAttributesToRender(HtmlTextWriter writer)
		{
			writer.AddAttribute(HtmlTextWriterAttribute.Name, this.UniqueID);
			if(this.Size > 0)
				writer.AddAttribute(HtmlTextWriterAttribute.Size, this.Size.ToString());
			writer.AddAttribute("label",this.Label);
			base.AddAttributesToRender (writer);
		}

		protected override void Render(HtmlTextWriter writer)
		{
			writer.Write("<?XML:NAMESPACE PREFIX=BESTCOMY />"+Environment.NewLine);
			writer.Write("<?IMPORT NAMESPACE=BESTCOMY IMPLEMENTATION=\"Bestcomy/InputFile.ashx\" />"+Environment.NewLine);
			base.Render (writer);
		}

		protected override void OnInit(EventArgs e)
		{
			base.OnInit (e);
			
			foreach(Control ctrl in this.Page.Controls)
			{
				if(ctrl is HtmlForm)
				{
					HtmlForm fm = (HtmlForm)ctrl;
					if(fm.Enctype == string.Empty)
						fm.Enctype = "multipart/form-data";
				}
			}
		}

	}
}