實現從sql server存取二進制圖片

轉：http://www.cnblogs.com/jeffwongishandsome/archive/2009/08/27/1554440.html

1、存取圖片
（1）、將圖片文件轉換為二進制並直接存進sql server

//UploadHelper.cs
     /// <summary>
    /// 將圖片轉化為長二進制
    /// </summary>
    /// <param name="photopath"></param>
    /// <returns></returns>
    public static Byte[] SetImgToByte(string imgPath)
    {
        FileStream file = new FileStream(imgPath, FileMode.Open, FileAccess.Read);
        Byte[] byteData = new Byte[file.Length];
        file.Read(byteData, 0, byteData.Length);
        file.Close();
        return byteData;
    }

    /// <summary>
    /// 將轉換成二進制碼的圖片保存到數據庫中
    /// </summary>
    public static bool SaveEmployeeImg2Db(Employee model, string path)
    {
        try
        {
            Byte[] imgBytes = SetImgToByte(path);
            model.Photo = imgBytes;
            bool flag=EmployeeService.SaveEmployeePhoto(model); //EmployeeService是公司內部的庫調用，插入或者更新照片，這里不透露細節
            return flag;

        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

//將圖片轉換為字節流
FileStream fileStream = new FileStream(path + fileName, FileMode.Open, FileAccess.Read);
Byte[] byteData = new Byte[fileStream.Length];
fileStream.Read(byteData, 0, byteData.Length);
fileStream.Close();

a.Picture = byteData;//賦值
int result = _accessoryRepository.Update(a);//操作


//ADO.NET

SqlParameter p_Picture = new SqlParameter("@Picture", SqlDbType.Image);
p_Picture.Value = obj.Picture;

（2）、在網頁中上傳圖片

/// <summary>
    /// 上傳圖片
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void btnUpload_Click(object sender, EventArgs e)
    {
        string serverPath = Server.MapPath("~/images/");
        if (this.fuPhoto.HasFile) //fuPhoto是fileupload控件
        {
            string fileName = this.fuPhoto.PostedFile.FileName;
            FileInfo fi = new FileInfo(fileName);
            string mimeType = this.fuPhoto.PostedFile.ContentType.ToLower();
            if (mimeType.IndexOf("image") < 0)
            {
                //("上傳的照片格式不對");
            }
            else if(fi.Length > 2* 1024 * 1024)
            {
                //圖片大於2M，重新處理
            }
            else
            {
                string saveFilePath = serverPath + DateTime.Now.ToString("yyyyMMddHHmmss") + fileName;
                try
                {
                    //先存圖片到服務器
                    this.fuPhoto.PostedFile.SaveAs(saveFilePath);

                    //轉成二進制
                    Employee model = new Employee(int.Parse(id)); //id是EmployeeId，這里是模擬字段
                    bool flag = UploadHelper.SaveEmployeeImg2Db(model, saveFilePath);
                }
                catch
                {
                    //("照片上傳失敗");
                }
                finally
                {
                    //最后刪掉該圖片
                    if (System.IO.File.Exists(saveFilePath))
                    {
                        System.IO.File.Delete(saveFilePath);
                    }
                }
            }
        }
        else
        {
            //("全選擇要上傳的照片");
        }
    }

（3）、從數據庫取出照片（返回格式Image）

//UploadHelper.cs
     /// <summary>
    /// 將二進制轉化為圖片Image
    /// </summary>
    /// <param name="photopath"></param>
    /// <returns></returns>
    public static System.Drawing.Image GetImgFromByte(Employee model)
    {
        System.Drawing.Image img = null;
        try
        {
            Stream stream = new MemoryStream(model.Photo);
            img = System.Drawing.Image.FromStream(stream,false);
        }
        catch 
        {
            img = null;
        }
        return img;
    }

上面的這個方法取出來之后，如果在winform下，直接給一個PictureBox的Image屬性賦值就可以了。可是web下沒有這么強大的控件，所以，就有了下面的步驟。

2、直接在網頁中以流的形式顯示圖片
（1）、生成圖片流頁面（ImgHelper .aspx）
這個頁面的設計頁面什么也沒有，類文件如下：

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Generic;
using System.IO;

/// <summary>
/// 圖片輔助類
/// </summary>
public partial class ImgHelper : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!string.IsNullOrEmpty(Request["employeeId"])) //需要顯示照片的頁面傳遞的員工id
        {
            int employeeId = int.Parse(Request["employeeId"]);
            Employee model = //EmployeeService.GetEmployeeByCondition(new Employee(employeeId))[0] as Employee; //內部函數 查找一個員工 不透漏細節
            try
            {
                Byte[] byteImg = model.Photo;
                Stream stream = new MemoryStream(byteImg);
                System.Drawing.Bitmap img =(System.Drawing.Bitmap) System.Drawing.Bitmap.FromStream(stream, false); //轉換成Bitmap 
                Response.Buffer = false;
                Response.ContentType = "image/jpg";
                Response.AddHeader("Content-Disposition", "attachment;filename=photo.jpg");//照片名稱叫photo.jpg
                Response.BinaryWrite(byteImg);//寫入二進制流
                  Response.End();
            }
            catch
            {
                Response.End();
            }
        }
    }
}

（2）、顯示照片的頁面調用ImgHelper .aspx
在頁面加載的時候，給圖片控件賦值如下：

 this.imgPhoto.ImageUrl = "/ImgHelper.aspx?employeeId="+tmpEmployee.Id.ToString(); //imgPhoto是圖片控件

 

/// <summary> 
   /// 為圖片生成縮略圖   
   /// </summary> 
   /// <param name="phyPath">原圖片的路徑</param> 
   /// <param name="width">縮略圖寬</param> 
   /// <param name="height">縮略圖高</param> 
   /// <returns></returns> 
   public System.Drawing.Image GetThumbnail(System.Drawing.Image image, int width, int height) 
   { 
       Bitmap bmp = new Bitmap(width, height); 
       //從Bitmap創建一個System.Drawing.Graphics 
       System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp); 
       //設置  
       gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; 
       //下面這個也設成高質量 
       gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality; 
       //下面這個設成High 
       gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; 
       //把原始圖像繪制成上面所設置寬高的縮小圖 
       System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(0, 0, width, height); 
    
       gr.DrawImage(image, rectDestination, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel); 
       return bmp; 
   }