图片上传存取图片路径和图片数据 以及给上传的图片加文字和图片水印

一: 直接把图片放到某个文件夹中
1:<INPUT id="myFile" type="file" class="input" onChange="checkData()" size="34" name="myFile" runat="server">
2:判断过程
  <script>
  function checkData()
  {
   var fileName=document.getElementById("myFile").value;
   if(fileName=="")
   return;
   var exName=fileName.substr(fileName.lastIndexOf(".")+1).toUpperCase()
   if(exName=="JPG"||exName=="BMP"||exName=="GIF")
   {
   document.getElementById("myimg").src=fileName
   }
   else
   {
   alert("请选择正确的图片文件")
   document.getElementById("myFile").value=""
   }
  }
  </script>
  <script language="javascript">
         window.resizeTo(400,250);
               </script>
3:上传图片路径到数据库
  private void btnSubmit_Click(object sender, System.EventArgs e)
  {
   string strImageName="";
   string FileName=myFile.Value;
   string Publishtime=DateTime.Now.ToString();
   string svrid=this.Hidden_svrid.Value.ToString();
   string modelid=this.Hidden_modelid.Value.ToString();
   string itemid=this.Hidden_itemid.Value.ToString();

   string slocal_ip=Request.ServerVariables["REMOTE_HOST"];
   string sregtime=System.DateTime.Now.ToString();
   string exName=FileName.Substring(FileName.LastIndexOf(".")+1).ToUpper();//截取图片的后缀名
   
   string fn=myFile.PostedFile.FileName;
   string imghead=svrid+"_";
   string SaveName=imghead+DateTime.Now.ToString("yyyyMMddhhmmssfff");//根据时间生成图片名
   strImageName=SaveName+fn.Substring(fn.LastIndexOf("."));//图片名加上图片后缀名
   string strpath=Server.MapPath("")+"//upimage//"+"//"+this.Session_UserID+"//";//得到将要保存图片的路径
   string saveimg="upimage/"+this.Session_UserID+"/"+strImageName;
   string savepath=strpath+strImageName;
   string sqlread;
   string sqladd;
   if(itemid=="")
   {
    sqlread="select pic_path from BZ_Data_pic where Busi_id='"+this.Session_UserID+"' and Modal_id='"+modelid+"' and svrID='"+svrid+"'";
    sqladd="insert into BZ_Data_pic(Modal_id,SvrID,Busi_id,pic_path,Reg_time,Local_ip) values('"+modelid+"','"+svrid+"','"+this.Session_UserID+"','"+saveimg+"','"+sregtime+"','"+slocal_ip+"')";
   }
   else
   {
    sqlread="select pic_path from BZ_Data_ModalItemPic where Busi_id='"+this.Session_UserID+"' and Modal_id='"+modelid+"' and Item_ID='"+itemid+"' and svrID='"+svrid+"'";
    sqladd="insert into BZ_Data_ModalItemPic(Modal_id,SvrID,Busi_id,Item_ID,pic_path,Reg_time,Local_ip) values('"+modelid+"','"+svrid+"','"+this.Session_UserID+"','"+itemid+"','"+saveimg+"','"+sregtime+"','"+slocal_ip+"')";
   }
   System.Data.DataTable dt=Framework.ComLib.DataBase.Query(sqlread).Tables[0];
   //判断保存的图片张数
   if(dt.Rows.Count<3)
   {
    if(exName=="JPG"||exName=="BMP"||exName=="GIF")
    {
     if(myFile.PostedFile.ContentLength>204800)//判断图片是否大于200k
     {
      RegisterClientScriptBlock ("alertInfo","<script>alert('对不起，你上传的图片太大，请转换后上传')</script>");
      return;
     }
     if(System.IO.Directory.Exists(strpath) == false)
     {
      System.IO.Directory.CreateDirectory(strpath);

     }
     myFile.PostedFile.SaveAs(savepath);//把图片保存在此路径中
      
     Framework.ComLib.DataBase.ExecuteSql( sqladd);
     RegisterClientScriptBlock ("alertInfo","<script>window.opener.location.reload();window.opener.opener=null;window.close();</script>");
    }
    else
    {
     RegisterClientScriptBlock ("alertInfo","<script>alert('请选择正确的图片文件')</script>");
     return;
    }
   }
   else
   {
    RegisterClientScriptBlock ("alertInfo","<script>alert('最多只能上传3张图片');location.href=location.href;</script>");
   }
  }

二: 直接把图片放到数据库仲
一、文件（图片）保存到数据库
//得到用户要上传的文件名
            string strFilePathName = loFile.PostedFile.FileName;
            string strFileName = Path.GetFileName(strFilePathName);
            int FileLength = loFile.PostedFile.ContentLength;
            if(FileLength<=0)
                return;
            try
            {//上传文件
                Byte[] FileByteArray = new Byte[FileLength]; //图象文件临时储存Byte数组
                Stream StreamObject = loFile.PostedFile.InputStream; //建立数据流对像
                //读取图象文件数据，FileByteArray为数据储存体，0为数据指针位置、FileLnegth为数据长度
                StreamObject.Read(FileByteArray,0,FileLength);
                //建立SQL Server链接
                string strCon = System.Configuration.ConfigurationSettings.AppSettings["DSN"];
                SqlConnection Con = new SqlConnection(strCon);
                String SqlCmd = "INSERT INTO ImageStore (ImageData, ImageContentType, ImageDescription, ImageSize) VALUES (@Image, @ContentType, @ImageDescription, @ImageSize)";
                SqlCommand CmdObj = new SqlCommand(SqlCmd, Con);
                CmdObj.Parameters.Add("@Image",SqlDbType.Binary, FileLength).Value = FileByteArray;
                CmdObj.Parameters.Add("@ContentType", SqlDbType.VarChar,50).Value = loFile.PostedFile.ContentType; //记录文件类型
                //把其它单表数据记录上传
                CmdObj.Parameters.Add("@ImageDescription", SqlDbType.VarChar,200).Value = tbDescription.Text;
                //记录文件长度，读取时使用
                CmdObj.Parameters.Add("@ImageSize", SqlDbType.BigInt,8).Value = FileLength;
                Con.Open();
                CmdObj.ExecuteNonQuery();
                Con.Close();
                //跳转页面
                Response.Redirect("ShowAll.aspx");
            }
            catch
            {
            }
取出来显示：
int ImgID = Convert.ToInt32(Request.QueryString["ID"]); //ID为图片ID
            //建立数据库链接
            string strCon = System.Configuration.ConfigurationSettings.AppSettings["DSN"];
            SqlConnection Con = new SqlConnection(strCon);
            String SqlCmd = "SELECT * FROM ImageStore WHERE ImageID = @ImageID";
            SqlCommand CmdObj = new SqlCommand(SqlCmd, Con);
            CmdObj.Parameters.Add("@ImageID", SqlDbType.Int).Value = ImgID;
            Con.Open();
            SqlDataReader SqlReader = CmdObj.ExecuteReader();
            SqlReader.Read();
            Response.ContentType = (string)SqlReader["ImageContentType"];//设定输出文件类型
            //输出图象文件二进制数制
            Response.OutputStream.Write((byte[])SqlReader["ImageData"], 0, (int)SqlReader["ImageSize"]);
            Response.End();
            //也可以保存为图像
//            FileStream fs = new FileStream(@"C:/aa.BMP", FileMode.OpenOrCreate, FileAccess.Write);
//            fs.Write((byte[])SqlReader["ImageData"], 0,(int)SqlReader["ImageSize"]);
//            fs.Close();

            Con.Close();
三 在WinForm环境中把图片放在数据库中

System.Data.SqlClient.SqlConnection conn  =   new  SqlConnection(sqlconnstr);
            System.Data.SqlClient.SqlCommand cmd  =   new  SqlCommand( " insert imgtable values(@name,@data) " ,conn);
            System.Data.SqlClient.SqlParameter pm  =   new  SqlParameter( " @name " ,System.Data.SqlDbType.VarChar, 200 );
            pm.Value  =  fname;
            System.Data.SqlClient.SqlParameter pm1  =   new  SqlParameter( " @data " ,System.Data.SqlDbType.Image);
            System.IO.FileStream fs  =   new  System.IO.FileStream(fname,System.IO.FileMode.Open);
             int  len  =  ( int )fs.Length;
            System.Byte[] fileData  =   new   byte [len];
            fs.Read(fileData, 0 ,len);
            fs.Close();
                        pm1.Value  =  fileData;
                        cmd.Parameters.Add(pm);
            cmd.Parameters.Add(pm1);
            conn.Open();
             try
             ... {
                cmd.ExecuteNonQuery();
                MessageBox.Show("Save Picture to database succeed");
            }
             catch (System.Exception ex)
             ... {
                MessageBox.Show(ex.ToString());
            }

读取的过程

System.Data.SqlClient.SqlConnection conn  =   new  SqlConnection(sqlconnstr);
            System.Data.SqlClient.SqlCommand cmd  =   new  SqlCommand( " select * from imgtable where imgname like '%bmp%' " ,conn);
            conn.Open();
            System.Data.SqlClient.SqlDataReader dr;
             try
             ... {
                dr = cmd.ExecuteReader();
                while(dr.Read())
                ...{
                   System.Data.SqlTypes.SqlBinary sb = dr.GetSqlBinary(2);
                   System.IO.MemoryStream stm = new System.IO.MemoryStream(sb.Value);
                   System.Drawing.Bitmap bmp = new Bitmap(Bitmap.FromStream(stm));
                   this.pictureBox1.Image = bmp;
                }
                dr.Close();
            }
             catch
             ... {

            }
             finally
             ... {
                conn.Close();
            }

说明：Sql Server 数据库中 Image/Text这两种数据类型都是容量比较大的数据类型，单字段可以存取2GB的数据，而普通的字段不能超过
8K，Text通常用来保存大文本数据，可直接用字符串判断检索，Image通常用来保存二进制数据，不可直接用字符串判断检索

四 给图片加文字和图片水印

private   void  Btn_Upload_Click( object  sender, System.EventArgs e)
  ... {
 if(UploadFile.PostedFile.FileName.Trim()!="")
 ...{
 //上传文件
 string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToUpper();
 string fileName = DateTime.Now.ToString("yyyyMMddhhmmss");
 string path = Server.MapPath(".") + "/UploadFile/" + fileName + extension;
 UploadFile.PostedFile.SaveAs(path);

 //加文字水印，注意，这里的代码和以下加图片水印的代码不能共存
 System.Drawing.Image image = System.Drawing.Image.FromFile(path);
 Graphics g = Graphics.FromImage(image);
 g.DrawImage(image, 0, 0, image.Width, image.Height);
 Font f = new Font("Verdana", 32);
 Brush b = new SolidBrush(Color.White);
 string addText = AddText.Value.Trim();
 g.DrawString(addText, f, b, 10, 10);
 g.Dispose();

 //加图片水印
 System.Drawing.Image image = System.Drawing.Image.FromFile(path);
 System.Drawing.Image copyImage = System.Drawing.Image.FromFile( Server.MapPath(".") + "/Alex.gif");
 Graphics g = Graphics.FromImage(image);
 g.DrawImage(copyImage, new Rectangle(image.Width-copyImage.Width, image.Height-copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
 g.Dispose();

 //保存加水印过后的图片,删除原始图片
 string newPath = Server.MapPath(".") + "/UploadFile/" + fileName + "_new" + extension;
 image.Save(newPath);
 image.Dispose();
 if(File.Exists(path))
 ...{
 File.Delete(path);
 }

 Response.Redirect(newPath);
 }
 }
//  注意：加文字水印和加图片水印的代码不能共存