如何在C#中把数据库里的二进制图片转换成jpg格式

Image.Save(
Stream stream,
ImageFormat format
);

TypeConverter.ConvertFrom
public object ConvertFrom(
object value
);
将给定值转换为此转换器的类型。

hdt(倦怠) 你能说清楚点吗，我是新手，谢谢

void savejpg(String NAME)
{
    SqlConnection CON = new SqlConnection();
    SqlCommand CMD = new SqlCommand("SQL");    FileStream fs;
    BinaryWriter bw;    int bufferSize = 1024;
    byte[] outbyte = new byte[bufferSize];
    long retval;
    long startIndex = 0;    CON.Open();
    SqlDataReader myReader = CMD.ExecuteReader(CommandBehavior.SequentialAccess);    while (myReader.Read())
    {
        fs = new FileStream(NAME, FileMode.OpenOrCreate, FileAccess.Write);
        bw = new BinaryWriter(fs);        startIndex = 0;
        retval = myReader.GetBytes(0, startIndex, outbyte, 0, bufferSize);        while (retval > 0)
        {
            bw.Write(outbyte);
            bw.Flush();
            startIndex += bufferSize;
            retval = myReader.GetBytes(0, startIndex, outbyte, 0, bufferSize);
        }        bw.Write(outbyte);
        bw.Flush();        bw.Close();
        fs.Close();
    }    myReader.Close();
    CON.Close(); }
类似

从数据读图片代码比较长
就不写了byte[] barrImage = 数据库存图片的二进制字段值
MemoryStream ms = new MemoryStream( barrImage );
Image image = Image.FormStream(ms);
image.Save( Response.OutputStream ， ImageFormat.Jpeg )

Image 的引用为什么总是报错，不是using System.Drawing.Imaging;吗

命名空间: System.Drawing

为什么还是报Image是不明确的引用

c:\inetpub\wwwroot\WebApporacle\WebForm1.aspx.cs(51): 找不到类型或命名空间名称“image”(是否缺少 using 指令或程序集引用？)

c:\inetpub\wwwroot\WebApporacle\WebForm1.aspx.cs(50): “Image”是不明确的引用

考虑是否你的程序里有叫Image的类
另用System.Drawing.Image 代替Image

用System.Drawing.Image 代替Image应该不会再报不明确的引用

private Image RenderImage(byte[] byteImg)
{
System.Drawing.Image image1 = System.Drawing.Image.FromStream(new MemoryStream(byteImg));
return image1;
}

System.Drawing.Image image = System.Drawing.Image.FromStream(ms,true);
使用了无效参数。

大家帮我看看代码吗
public string bind()
{
StringBuilder sb=new StringBuilder();
strsql="select docid,fileid,rowed,filecon from docmapfile";
OracleDataAdapter da = new OracleDataAdapter(strsql,conn);
da.Fill(ds);

this.text1.Value=ds.Tables[0].Rows[0].ItemArray[0].ToString();
this.text2.Value=ds.Tables[0].Rows[0].ItemArray[1].ToString();
this.text3.Value=ds.Tables[0].Rows[0].ItemArray[2].ToString(); byte[] barrImage=(byte[])ds.Tables[0].Rows[0].ItemArray[3];
MemoryStream ms = new MemoryStream(barrImage);
System.Drawing.Image image = System.Drawing.Image.FromStream(ms,true);
image.Save( Response.OutputStream , ImageFormat.Jpeg );
sb.Append(image.ToString()); conn.Close();

return sb.ToString();
}

MemoryStream ms = new MemoryStream( barrImage );
Image image = Image.FormStream(ms,true);
image.Save( Response.OutputStream ，ImageFormat.Jpeg )
关键就是这里

我就是System.Drawing.Image image = System.Drawing.Image.FromStream(ms,true);
这里报错，使用了无效参数。

to 我就是System.Drawing.Image image = System.Drawing.Image.FromStream(ms,true);
这里报错，使用了无效参数。我刚遇到了个类似的错误,请检查一下你的ms是否已经保存了内容.
可能是你的ms根本没有取到值.

插入时把图片数据作为Byte数组插入数据库,下面是把文件转换成数组
private byte[] ReadImageData(string strFileName)
{
   byte[] BlobData = null;
   Bitmap picture;
   FileStream stream;
   stream = new FileStream(strFileName,FileModel.Open,FileAccess.Read);
   BlobData = new byte[stream.Length];
   stream.Read(BlobData,0,(int)stream.Length);
   picture = new Bitmap(stream);
   stream.Close();
   return BlobData;
}从数据库中读取图片文件数据转换成byte数组,下面是如何将数组转换为图片private Bitmap GetBitmap(byte[] img)
{
   if(img != null)
   {
      MemoryStream ms = new MemoryStream(img,true);
      ms.Read(img,0,img.Length);
      Bitmap bmp = new Bitmap(ms);
      ms.Close();
      return bmp;
   }
   else
      return null;
}

this.oracleConnection1.Open();
byte[] pic = (byte[])ocm.ExecuteScalar();//这个命令只返回图象数据
this.oracleConnection1.Close();
System.IO.MemoryStream ms = new System.IO.MemoryStream(pic);
System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
this.pictureBox1.Image = img;

to 我的ms里面有值，我调试看了的，除了这里，那里还有错吗？如果你的ms中有值，就不应该提示这个错误了，
它还报什么错？

public void bindphoto(string xh,PictureBox pictureBox1)
{
dbcontroller obj=new dbcontroller();
string sql="SELECT * FROM photo WHERE xh='" + xh + "'";
obj.open();
DataSet myphotods = obj.GetDs(sql);
obj.close();
if (myphotods.Tables[0].Rows.Count > 0)
{
byte[] bytephoto = new byte[0];
bytephoto = (byte[])(myphotods.Tables[0].Rows[0]["ZP"]);
MemoryStream stmPhoto = new MemoryStream(bytephoto);
pictureBox1.Image = Image.FromStream(stmPhoto);
}
else
{
pictureBox1.Image = null;
}
}

我是用winform作的图片存入数据库，然后通过web显示出来

是CS模式的,还是BS模式的程序?

哦,这我倒没试过,我这有一个用OPENDIALOG控件(CS模式下)和使用UploadFile控件(BS模式下)的存图片的函数!
//=============================================================
// 函数名：Savephoto
// 功能描述：添加或修改照片
// 输入参数：学生学号，已经打开文件的openFileDialog
// 返回值：无
//=============================================================
public void Savephoto(string xh,OpenFileDialog openFileDialog1)
{
//定义byte类型变量
byte[] myblob = null;
Stream fs;
//给变量blob赋值
fs =openFileDialog1.OpenFile();
if(fs!=null)
{
openFileDialog1.Reset();
myblob = new byte[fs.Length];
fs.Read(myblob,0,int.Parse(myblob.Length.ToString()));
fs.Close();
OracleDataAdapter myoda;
OracleCommand cmd;
DataSet myds = new DataSet();
DataTable mydt = new DataTable();
DataRow mydr;
string connstr="User ID=student;Data Source=hres;Password=studentmanage";
OracleConnection conn= new OracleConnection(connstr);
string selesql;
selesql = "SELECT * FROM photo WHERE xh='" + xh + "'";
cmd = new OracleCommand(selesql,conn);
myoda = new OracleDataAdapter(selesql,conn);
myoda.SelectCommand = cmd;
myoda.Fill(myds, "PHOTO");
string info = "";
if (myds.Tables[0].Rows.Count > 0)//修改照片
{
info = "修改照片成功";
string updatesql = "UPDATE photo SET zp=:vPHOTO WHERE xh='" + xh + "'";
OracleCommand updatecmd = new OracleCommand(updatesql,conn);
myoda.UpdateCommand = updatecmd;
myoda.UpdateCommand.Parameters.Add(":vPHOTO", OracleType.Blob, myblob.Length, "ZP"); myoda.MissingSchemaAction = MissingSchemaAction.AddWithKey;
myoda.FillSchema(myds, SchemaType.Source, "PHOTO");
myoda.Fill(myds, "PHOTO"); mydt = myds.Tables[0];
mydr = mydt.Rows[0];
string a = mydr["XH"].ToString(); mydr.BeginEdit();
mydr["XH"] = xh;
mydr["ZP"] = myblob;
mydr.EndEdit();
myoda.Update(myds, "PHOTO");
}
else//上传新照片
{
info = "上传新照片成功";
string insertsql = "INSERT INTO photo (xh,zp) VALUES ('" + xh + "',:vPHOTO)";
OracleCommand insertcmd = new OracleCommand(insertsql,conn);
myoda.InsertCommand = insertcmd;
myoda.InsertCommand.Parameters.Add(":vPHOTO", OracleType.Blob, myblob.Length, "ZP"); myoda.MissingSchemaAction = MissingSchemaAction.AddWithKey;
myoda.FillSchema(myds, SchemaType.Source, "PHOTO");
myoda.Fill(myds, "PHOTO"); mydt = myds.Tables[0];
mydr = mydt.NewRow(); mydr.BeginEdit();
mydr["XH"] = xh;
mydr["ZP"] = myblob;
mydr.EndEdit();
mydt.Rows.Add(mydr);
myoda.Update(myds, "PHOTO");
}
MessageBox.Show(info);
}
}

/// 上传图片
private void SavePhoto(string xh)
{
if(IsAllowedExtension(UploadFile))
{
//如果是修改图片,则将修改前图片删掉
string[] arrExtension = {".gif",".jpg",".jpeg",".bmp",".png"};
string path1="";
//判断该扩展名是否合法
for(int i = 0; i< arrExtension.Length; i++)
{
string fileName1=TextBox_xh.Text;
path1=Server.MapPath(".") + @"\Photo\" +fileName1+arrExtension[i];
if(File.Exists(path1))
{
FileInfo delete=new FileInfo(path1);
delete.Delete();
break;
}
}
//上传图片
string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToLower();// string extension=".jpg";
string fileName=TextBox_xh.Text;
string path = Server.MapPath(".") + @"\Photo\" + fileName + extension;
//保存图片到服务器目录下
UploadFile.PostedFile.SaveAs(path);
//得到图片的二进制形式
HttpPostedFile upFile=UploadFile.PostedFile;
//得到上传文件的长度；
int upFileLength=upFile.ContentLength;
string ContentType=upFile.ContentType;
byte[] bPicture;
bPicture=new byte[upFileLength];
Stream filestream=upFile.InputStream ;
filestream.Read (bPicture,0,upFileLength);
filestream.Close ();
OracleDataAdapter myoda;
DataSet myds = new DataSet();
System.Data.DataTable mydt = new System.Data.DataTable();
DataRow mydr;
OracleCommand cmd;
string connstr="User ID=student;Data Source=hers;Password=studentmanage";
OracleConnection conn= new OracleConnection(connstr);
string selesql = "SELECT * FROM photo WHERE xh='" + xh + "'";
cmd = new OracleCommand(selesql,conn);
myoda = new OracleDataAdapter(selesql,conn);
myoda.SelectCommand = cmd;
myoda.Fill(myds, "PHOTO");
string insertsql = "INSERT INTO photo (xh,zp) VALUES ('" + xh + "',:vPHOTO)";
string updatesql = "UPDATE photo SET zp=:vPHOTO WHERE xh='" + xh + "'";
try
{
if(myds.Tables[0].Rows.Count > 0)
{
OracleCommand updatecmd = new OracleCommand(updatesql,conn);
myoda.UpdateCommand = updatecmd;
myoda.UpdateCommand.Parameters.Add(":vPHOTO", OracleType.Blob, bPicture.Length, "ZP");
myoda.MissingSchemaAction = MissingSchemaAction.AddWithKey;
myoda.FillSchema(myds, SchemaType.Source, "PHOTO");
myoda.Fill(myds, "PHOTO");
mydt = myds.Tables[0];
mydr = mydt.Rows[0];
string a = mydr["XH"].ToString();
mydr.BeginEdit();
mydr["XH"] = xh;
mydr["ZP"] = bPicture;
mydr.EndEdit();
myoda.Update(myds, "PHOTO");
pictureBox1.ImageUrl=path;
}
else
{
OracleCommand insertcmd = new OracleCommand(insertsql, conn);
myoda.InsertCommand = insertcmd;
myoda.InsertCommand.Parameters.Add(":vPHOTO", OracleType.Blob,bPicture.Length, "ZP");
myoda.MissingSchemaAction = MissingSchemaAction.AddWithKey;
myoda.FillSchema(myds, SchemaType.Source, "PHOTO");
myoda.Fill(myds, "PHOTO");
mydt = myds.Tables[0];
mydr = mydt.NewRow();
mydr.BeginEdit();
mydr["XH"] = xh;
mydr["ZP"] = bPicture ;
mydr.EndEdit();
mydt.Rows.Add(mydr);
myoda.Update(myds, "PHOTO");
pictureBox1.ImageUrl=path;
}
}
catch
{
throw;
}
}
}

调试易

如何在C#中把数据库里的二进制图片转换成jpg格式

解决方案 »