C# 从 sql server 数据库中检索图像
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Retrieve Images from sql server database
提问by Geeth
i am storing images to the database. How to retrieve all the images from the database.
我正在将图像存储到数据库中。如何从数据库中检索所有图像。
Eg: select images from imagetable
例如：从 imagetable 中选择图像
Problem:
问题：
Data Logic:
数据逻辑：
while (dr.Read())
{
///Check for null
if (!dr.IsDBNull(0))
{
try
{
///Converting the image into bitmap
byte[] photo = (byte[])dr[0];
ms = new MemoryStream(photo);
Bitmap bm = new Bitmap(ms);
bmp[i] = bm;
ms.Close();
}
catch (Exception ex)
{
}
}
ASpx.CS page:
ASpx.CS 页面：
Bitmap[] bm= photos.GetImage();
for (int i = 0; i < bm.Length; i++)
{
MemoryStream ms = new MemoryStream();
**bm[i].Save(ms, ImageFormat.Jpeg);**(Error : A generic error occurred in GDI+.)
htmlCode.Append("<li><img ImageUrl=\\"");
htmlCode.Append(**ms.GetBuffer()**);
htmlCode.Append("\" alt=\"\" width=\"100\" height=\"100\"></li>");
}
Image not getting displayed
图像未显示
Geetha
吉塔
采纳答案by Yevhen
this is an example from Sql Server
这是来自 Sql Server 的一个例子
connection.Open();
SqlCommand command1 = new SqlCommand("select imgfile from myimages where imgname=@param", connection);
SqlParameter myparam = command1.Parameters.Add("@param", SqlDbType.NVarChar, 30);
myparam.Value = txtimgname.Text;
byte[] img = (byte[])command1.ExecuteScalar();
MemoryStream str = new MemoryStream();
str.Write(img, 0, img.Length);
Bitmap bit = new Bitmap(str);
connection.Close();
look here http://www.akadia.com/services/dotnet_read_write_blob.html
看这里 http://www.akadia.com/services/dotnet_read_write_blob.html
回答by Mitch Wheat
For SQL Server 2008 onwards, FILESTREAM is almost certainly the way to go.
对于 SQL Server 2008 以后的版本，FILESTREAM 几乎肯定是要走的路。
Please see: SQL Server 2005 - How do I convert image data type to character format
回答by Fitzchak Yitzchaki
You need to get the binary data from the DB, and then stream the binary data to the browser as image.
您需要从数据库中获取二进制数据，然后将二进制数据作为图像流式传输到浏览器。
回答by cjk
You are setting the Url of the image to be the byte stream - you need to save the image to the hard drive and provide the location.
您将图像的 Url 设置为字节流 - 您需要将图像保存到硬盘驱动器并提供位置。
A much better way would be to set the image url to be a resource handler with parameters that could then retrieve the image from the database and return it as a stream to the browser.
更好的方法是将图像 url 设置为带有参数的资源处理程序，然后可以从数据库中检索图像并将其作为流返回到浏览器。
