使用asp.net中的数据库将图像转换为二进制和二进制到图像 [英] to Convert image to binary and binary to image using database in asp.net

问题描述

您好......



我想将图像转换为二进制并将其保存在数据库中...并将二进制数据恢复到图像和上传该图片..



我的代码如...

Hello......

I want to convert image to binary and save it in database...and also get back binary data to image and upload that image..

I have code like..

 private System.Drawing.Image BinaryToImage(byte[] b)
    {
        if (b == null)
            return null;
        MemoryStream memstream = new MemoryStream();
        memstream.Write(b, 0, b.Length);
        return System.Drawing.Image.FromStream(memstream);
    }

//for view
GridViewRow gridViewRow = CategoryGridView.SelectedRow;
            SqlDataReader dr = null;

            try
            {
                string qry = "select * from Category where cat_id =" + gridViewRow.Cells[1].Text;
                cmd = new SqlCommand(qry, cn);
                dr=cmd.ExecuteReader();
                if (dr.Read())
                {
                    lblcat_id.Text = dr[0].ToString();
                    txt_categorynm.Text = dr[1].ToString();
                    byte[] b = (byte[])dr[2];
                    System.Drawing.Image img = BinaryToImage(b);
                    string filepath = "User_image" + "//" + lblcat_id.Text + ".png";
                    FileStream fs = File.Create(filepath);
                    fs.Write(b, 0, b.Length);
                    fs.Flush();
                    fs.Close();
                    Image1.ImageUrl = "~/" + filepath;
                }
                else { }

            }
            catch
            {

            }

plz，给mi解决方案..

谢谢你..

plz,give mi solution..
thank u..

推荐答案

我认为您的 BinaryToImage 方法存在问题。在向其写入字节后，您需要将流的位置移动到流的开头：

I think there is a problem in your BinaryToImage method. After writing the bytes to it, you need to move the position of the stream to the beginning of the stream:

private System.Drawing.Image BinaryToImage(byte[] b)
   {
       if (b == null)
           return null;
       MemoryStream memstream = new MemoryStream();
       memstream.Write(b, 0, b.Length);
       memstream.Seek(0, SeekOrigin.Begin);
       return System.Drawing.Image.FromStream(memstream);
   }

如果这不起作用，那么图片可能会错误地存储在您的数据库中：

为什么我会得到一个参数无效。我从数据库中读取图像时出现异常？ [ ^ ]

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