asp.net，c#上传图片生成缩略图

根据网上代码自己该动了些

#region 上传图片到数据库

private void UpIMGButton_Click(object sender, System.EventArgs e)

{

string exName=UpFile.Value.Substring(UpFile.Value.LastIndexOf(".")+1).ToUpper();//找出图片的后缀名

string ImgName=DateTime.Now.ToString("yyyyMMddhhmmssfff")+"."+exName;

if (UpFile.PostedFile.ContentLength==0)

{

Response.Write("<script> alert('你上传的图片不能为空!');</script>");

}

else

{

try

{

Byte[] FileByte = new byte[UpFile.PostedFile.ContentLength];

Stream ObjectStream = UpFile.PostedFile.InputStream;

ObjectStream.BeginRead(FileByte,0,UpFile.PostedFile.ContentLength,null,null);

string imgType=UpFile.PostedFile.ContentType;

Byte[] SmallFileByte = new byte[UpFile.PostedFile.ContentLength];

SmallFileByte=CreateThumnail(ObjectStream,100,100);

string ConStr ="U;

SqlConnection Conn = new SqlConnection(ConStr);

Conn.Open();

SqlCommand myCommand =new SqlCommand();

myCommand.Connection=Conn;

myCommand.CommandText="insert into [UpImage] (imageName,image,imgType,SmallImage) values (@ImgName,@FileByte,@imgType,@SmallImage)";

myCommand.Parameters.Add("@ImgName",ImgName);

myCommand.Parameters.Add("@FileByte",FileByte);

myCommand.Parameters.Add("@imgType",imgType);

myCommand.Parameters.Add("@SmallImage",SmallFileByte);

myCommand.ExecuteNonQuery();

Response.Write("<script> alert('图片保存到数据库成功!');</script>");

}

catch(Exception ex)

{

Response.Write (ex.Message);

}

}

}

#endregion

#region 生成缩略图

private Byte[] CreateThumnail(Stream ImageStream,int tWidth, int tHeight)

{

System.Drawing.Image g = System.Drawing.Image.FromStream(ImageStream);

int[] thumbSize = new int[]{1,1};

thumbSize = NewthumbSize(g.Width, g.Height, tWidth, tHeight);

Bitmap imgOutput = new Bitmap(g, thumbSize[0], thumbSize[0]);

MemoryStream imgStream = new MemoryStream();

System.Drawing.Imaging.ImageFormat thisFormat = g.RawFormat;

imgOutput.Save(imgStream, thisFormat);

Byte[] imgbin =new byte[imgStream.Length];

imgStream.Position = 0;

Int32 n = imgStream.Read(imgbin,0,imgbin.Length);

g.Dispose();

imgOutput.Dispose();

return imgbin;

}

#endregion

#region 根据上传图片调整缩略图的尺寸

protected int[] NewthumbSize(int currentwidth,int currentheight,int newWidth ,int newHeight)

{

int tempMultiplier;

if(currentheight > currentwidth)

{

tempMultiplier = newHeight / currentheight;

}

else

{

tempMultiplier = newWidth / currentwidth;

}

int[] NewSize = new int[]{(currentwidth * tempMultiplier),(currentheight * tempMultiplier)};

return NewSize;

}

#endregion

////图片显示页的代码

myCommand.CommandText="select smallimage from [UpImage] ";

SqlDataReader dr =db.myCommand.ExecuteReader();

this.Response.ContentType="image/gif";

while(dr.Read())

{

Response.BinaryWrite((byte[])dr["smallimage"]);

}