loadimages.cs

Csharp实例编程百例.rar

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.IO;

namespace LoadImagesApp 
{
	class LoadImages
	{
		string imageFileLocation =
			@"C:\Program Files\Microsoft Visual Studio .NET\"  +
			@"FrameworkSDK\Samples\QuickStart\aspplus\images\";

		string imageFilePrefix = "cereal";
		int numberImageFiles = 7;
		string imageFileType = ".gif";
		int maxImageSize = 10000;

		SqlConnection imageConnection = null;
		SqlCommand imageCommand = null;

		void openConnection() 
		{
			// create SqlConnection object
			imageConnection = new SqlConnection(
				@"Server=(local);" +     
				"Integrated Security=true;" +  
				"Connection Timeout=5;" +    
				"Database=NorthWind"
				);
			// Open connection
			imageConnection.Open();
		}
		void closeConnection() 
		{
			// close connection
			imageConnection.Close();
			// close was successful      
			Console.WriteLine("Connection Successfully Closed!");
		}
		void createCommand()
		{
			imageCommand = new SqlCommand();
			imageCommand.Connection = imageConnection;
		}
		void executeCommand(string commandText)
		{
			int commandResult;
			imageCommand.CommandText = commandText;
			Console.WriteLine("Executing command:");
			Console.WriteLine(imageCommand.CommandText);
			commandResult = imageCommand.ExecuteNonQuery();
			Console.WriteLine("ExecuteNonQuery returns {0}.", commandResult);
		}

		void createImageTable()
		{
			executeCommand( 
				"IF EXISTS ( " +
				" SELECT TABLE_NAME " +
				" FROM INFORMATION_SCHEMA.TABLES  " +
				" WHERE TABLE_NAME = 'imagetable' " +
				")      DROP TABLE imagetable "
			);

			executeCommand(  
				"CREATE TABLE imagetable ( " +
				" imagefile NVARCHAR(20),  " +
				" imagedata IMAGE" +			
				")"
			);
		}
		void prepareInsertImages()
		{
			imageCommand.CommandText = 
			  "INSERT INTO imagetable VALUES (@ImageFile, @ImageData)";
			imageCommand.Parameters.Add("@ImageFile", SqlDbType.NVarChar);
			imageCommand.Parameters.Add("@ImageData", SqlDbType.Image);
		}
		void executeInsertImages(int imageFileNumber)
		{
			string imageFileName = null;
			byte[] imageImageData = null;

			imageFileName = imageFilePrefix+ imageFileNumber.ToString()+ imageFileType;
			imageImageData = loadImageFile(imageFileName, imageFileLocation, maxImageSize);
	
			imageCommand.Parameters["@ImageFile"].Value = imageFileName;
			imageCommand.Parameters["@ImageData"].Value = imageImageData;	
			
			executeCommand(imageCommand.CommandText);

		}

		byte[] loadImageFile(string fileName, string fileLocation, int maxImageSize) 
		{
			byte[] imagebytes = null;
			string fullpath = fileLocation + fileName;
			Console.WriteLine("Loading File:");
			Console.WriteLine(fullpath);

			FileStream fs = new FileStream(fullpath, FileMode.Open);
			BinaryReader br = new BinaryReader(fs);
			imagebytes = br.ReadBytes(maxImageSize);

			Console.WriteLine("Imagebytes has length {0} bytes.", imagebytes.GetLength(0));
			return imagebytes;
		}

		static void Main() 
		{
			LoadImages loader = new LoadImages();

			try 
			{
				// open connection to database
				loader.openConnection();
				// create command object
				loader.createCommand();
				// create table
				loader.createImageTable();
				// prepare insert command
				loader.prepareInsertImages();

				int i;
				for (i = 1; i<=loader.numberImageFiles; i++)	
				{
					loader.executeInsertImages(i);
				}
			} 
			catch (SqlException ex)         // catch exception if database error
			{
				Console.WriteLine(ex.ToString());    // display details of error
			}
			finally 
			{
				loader.closeConnection();  				// close connection
			}
		}   
	}
}