我正在尝试检索存储在SQL Server中的JPEG文件,并使用img src =" filepath"将其显示在HTML中图像,这只是在其中显示一个带有X的微小图像框。
如何将图像直接显示为图像变量。这是带有剃须刀C#的HTML页面:
@{
int iFileID = 8;
string sPhotoDesc = "";
Image iPhotoImage = null;
}
<form>
<fieldset>
<legend>FileInput</legend>
<input type="file" id="fileinput" />
<input type='button' id='btnLoad' value='Load' onclick="@{iPhotoImage =
PhotoLibraryApp.PhotoData.SelectPhoto(iFileID, out sPhotoDesc); }">
<div id="editor"></div>
</fieldset>
<img src="@iPhotoImage" width="500" height="377">
这是一个相关的c#代码,在一个称为photodata.cs的单独文件中:
using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.Drawing;
using System.IO;
using System.Transactions;
namespace PhotoLibraryApp
{
public class PhotoData
{
private const string ConnStr =
"Data Source=.;Integrated Security=True;Initial
Catalog=PhotoLibrary;";
public static Image SelectPhoto(int photoId, out string desc)
{
const string SelectTSql = @"
SELECT
Description,
Photo.PathName(),
GET_FILESTREAM_TRANSACTION_CONTEXT()
FROM PhotoAlbum
WHERE PhotoId = @PhotoId";
Image photo;
string serverPath;
byte[] serverTxn;
using (TransactionScope ts = new TransactionScope())
{
using (SqlConnection conn = new SqlConnection(ConnStr))
{
conn.Open();
using (SqlCommand cmd = new SqlCommand(SelectTSql, conn))
{
cmd.Parameters.Add("@PhotoId", SqlDbType.Int).Value = photoId;
using (SqlDataReader rdr = cmd.ExecuteReader())
{
rdr.Read();
desc = rdr.GetSqlString(0).Value;
serverPath = rdr.GetSqlString(1).Value;
serverTxn = rdr.GetSqlBinary(2).Value;
rdr.Close();
}
}
photo = LoadPhotoImage(serverPath, serverTxn);
}
ts.Complete();
}
return photo;
}
private static Image LoadPhotoImage(string filePath, byte[] txnToken)
{
Image photo;
using (SqlFileStream sfs =
new SqlFileStream(filePath, txnToken, FileAccess.Read))
{
photo = Image.FromStream(sfs);
sfs.Close();
}
return photo;
}
}
}
尝试找到答案三天后,以下工作有效。摘要,一旦从数据库SQLFileStream代码返回iPhotoImage后,使用TurnimagetobyTearray将其转换为字节数组,然后将Imgbytes字节转换为字符串的IMGSTRING,该字符串在HTML中显示了图像。这是代码的其他片段:
@{
//Get the file ID you want to display
int iFileID = 8;
string sPhotoDesc = "";
Image iPhotoImage = null;
iPhotoImage = PhotoLibraryApp.PhotoData.SelectPhoto(iFileID, out
sPhotoDesc);
byte[] imgBytes =
PhotoLibraryApp.PhotoData.TurnImageToByteArray(iPhotoImage);
string imgString = Convert.ToBase64String(imgBytes);
}
我在我的Photodata类中添加了以下方法:
public static byte[] TurnImageToByteArray(Image img)
{
MemoryStream ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
return ms.ToArray();
}
以下是显示图像的HTML:
<img id="JpegImage" alt="Photo Alternative" src="data:image/jpeg;base64, @imgString">
付出了更多努力后,我发现我无法保存到jpeg图像的内存流中。这给出了普遍存在的总GDI错误。jpeg文件必须首先使用以下代码转换为BITMP图像,然后才能显示它们:
(var ms = new MemoryStream())
{
Bitmap bmp = new Bitmap(imageToConvert);
bmp.Save(ms, format);
return ms.ToArray();
}
另一个注意事项:JPEG文件作为位图的图像类型从SQL FileStream返回,这是我引起我尝试与@Amir Atasin的条目一起尝试的:GDI ,JPEG Image中发生了一个通用错误memorystream