我在使用 C# 在 .NET 应用程序中显示来自 SQL Server 数据库的图像时遇到一些问题。我已经让图像的保存部分正常工作,它将图像作为一系列再见存储在数据库中,但现在我在尝试显示它时遇到了问题。这是我所拥有的:
using System;
using System.Configuration;
using System.Web;
using System.IO;
using System.Data;
using System.Data.SqlClient;
public class ShowImage : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
Int32 empno;
if (context.Request.QueryString["id"] != null)
empno = Convert.ToInt32(context.Request.QueryString["id"]);
else
throw new ArgumentException("No parameter specified");
context.Response.ContentType = "image/jpeg";
Stream strm = ShowEmpImage(empno);
byte[] buffer = new byte[4096];
int byteSeq = strm.Read(buffer, 0, 4096);
while (byteSeq > 0)
{
context.Response.OutputStream.Write(buffer, 0, byteSeq);
byteSeq = strm.Read(buffer, 0, 4096);
}
//context.Response.BinaryWrite(buffer);
}
public Stream ShowEmpImage(int empno)
{
string conn = CodProbs.Main.GetDSN();
SqlConnection connection = new SqlConnection(conn);
string sql = "SELECT CoverPhoto FROM Galleries WHERE GalleryID = @GalleryID";
SqlCommand cmd = new SqlCommand(sql, connection);
cmd.CommandType = CommandType.Text;
cmd.Parameters.AddWithValue("@GalleryID", empno);
connection.Open();
byte[] img = System.Text.Encoding.Unicode.GetBytes(Convert.ToString(cmd.ExecuteScalar()));
try
{
return new MemoryStream((byte[])img);
}
catch
{
return null;
}
finally
{
connection.Close();
}
}
public bool IsReusable
{
get
{
return false;
}
}
这不会导致任何语法错误,并且似乎应该可以正常工作。在使用调试器单步执行后,我可以看到它正在从数据库中获取正确的数据。但是,我收到以下错误消息:“图像...无法显示,因为它包含错误。”
关于这里的问题有什么想法吗?
更新存储图像
public static int AddGallery(GalleryDS galleryDS)
{
DataRow gallery = galleryDS.Tables[0].Rows[0];
int result = 0;
string sql = @"insert into Galleries (Title, Description, GalleryCategoryID, CreateDate, CreatedBy, CoverPhoto)
values (@Title, @Description, @GalleryCategoryID, @CreateDate, @CreatedBy, @CoverPhoto)
select scope_identity()";
using (SqlConnection conn = new SqlConnection(Main.GetDSN()))
{
SqlCommand command = new SqlCommand(sql, conn);
command.Parameters.AddWithValue("@Title", gallery["Title"]);
command.Parameters.AddWithValue("@Description", gallery["Description"]);
command.Parameters.AddWithValue("@GalleryCategoryID", 0);
command.Parameters.AddWithValue("@CreateDate", DateTime.Now);
command.Parameters.AddWithValue("@CreatedBy", gallery["CreatedBy"]);
command.Parameters.Add("@CoverPhoto", SqlDbType.VarBinary, Int32.MaxValue);
command.Parameters["@CoverPhoto"].Value = gallery["CoverPhoto"];
conn.Open();
result = Convert.ToInt32(command.ExecuteScalar());
conn.Close();
}
return result;
}