showimagecs.aspx.cs

Telerik是很大的第三方软件制造商

using System;
using System.Data.OleDb;
using System.Drawing;
using System.IO;


namespace Telerik.EditorExamplesCSharp.Editor.Examples.DBImages
{
	public class ShowImage : System.Web.UI.Page
	{
		private void Page_Load(object sender, System.EventArgs e)
		{
			//Get the file information from the database
			OleDbConnection conn = new OleDbConnection(DefaultCS.ConnectionString);
			conn.Open();
			if(Request.QueryString["file"] == null)
			{
				WriteImage(GetEmptyImage());
				return;
			}

			string query = "SELECT {0} FROM Images WHERE FileName = '" + Request.QueryString["file"].Replace("'", "''") + "'";

			//Check if to get the thumbnail of a file, or to get the full file
			if((Request.QueryString["type"] != null) && (Request.QueryString["type"] == "thumb"))
			{
				query = String.Format(query, "Thumbnail");
			}
			else
			{
				query = String.Format(query, "FullImage");
			}

			//Get the image and display it
			OleDbCommand command = new OleDbCommand(query, conn);
			OleDbDataReader reader = command.ExecuteReader();
			if(reader.Read())
			{
				WriteImage((byte[])reader[0]);
			}
			else
			{
				//There was not such an image, so display the no_image image
				WriteImage(GetEmptyImage());
			}
		}

		/// <summary>
		/// Flushes a byte array to the output stream
		/// </summary>
		/// <param name="image"></param>
		private void WriteImage(byte[] image)
		{
			Response.Buffer = true;
			Response.Clear();
			Response.ContentType = "image/gif";
			Response.AddHeader("content-disposition", "attachment; filename=" + Request.QueryString["FileName"]);
			Response.BinaryWrite(image);
			Response.Flush();
			Response.End();
		}

		/// <summary>
		/// Creates an empty bitmap image and returns it as an array of bytes
		/// </summary>
		/// <returns></returns>
		private byte[] GetEmptyImage()
		{
			int height = DefaultCS.ThumbsHeight;
			int width = DefaultCS.ThumbsWidth;
			Bitmap empty = new Bitmap(width, height);
			MemoryStream ms = new MemoryStream();
			empty.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
			return ms.ToArray();
		}

		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			InitializeComponent();
			base.OnInit(e);
		}
		
		private void InitializeComponent()
		{    
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion
	}
}