小编典典

从asp.net中的数据库检索图像

c#

如何使用c#从asp.net中的sql数据库中检索图像。

我想从数据库中检索图像文件,然后在标签中显示图像。

我尝试此代码,但无法正常工作

aspx

 <asp:Image ID="Image1" runat="server" ImageUrl="" Height="150px" Width="165px" />

背后的代码

 Byte[] bytes = (Byte[])ds.Tables[0].Rows[0]["image"];
 Response.Buffer = true;
 Response.Charset = "";
 Response.Cache.SetCacheability(HttpCacheability.NoCache);
 Response.ContentType = "image/jpg";
 Response.BinaryWrite(bytes);
 Response.Flush();
 Response.End();

如何赋予ImageUrl=""此图片的链接???


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2020-05-19

共1个答案

小编典典

创建generic http handler如下

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 = ConfigurationManager.ConnectionStrings["EmployeeConnString"].ConnectionString;
         SqlConnection connection = new SqlConnection(conn);
         string sql = "SELECT empimg FROM EmpDetails WHERE empid = @ID";
         SqlCommand cmd = new SqlCommand(sql,connection);
         cmd.CommandType = CommandType.Text;
         cmd.Parameters.AddWithValue("@ID", empno);
         connection.Open();
         object img = cmd.ExecuteScalar();
         try
        {
            return new MemoryStream((byte[])img);
        }
        catch
        {
            return null;
        }
        finally
       {
            connection.Close();
       }
    }

    public bool IsReusable
    {
        get
        {
             return false;
        }
    }


}

并显示图像如下

 Image1.ImageUrl = "~/ShowImage.ashx?id=" + id;

下面有一些链接
在数据库中的GridView显示图像?
如何在Asp.net的图像控件中显示数据库中的图像?
使用C#http://www.dotnetcurry.com/ShowArticle.aspx?
ID=129从ASP.net中的数据库显示图像

2020-05-19