PDF文件使用asp.net从DataBase检索 [英] PDF File retrieving from DataBase using asp.net

问题描述

  string  SQL =   SELECT * FROM DPSpdf WHERE intpdfId =' + txtdanceid.Text +  '; 
 SqlCommand myCommand =  new  SqlCommand（SQL，（SqlConnection）Application.Get（  DPS））; 
 myCommand.Parameters.AddWithValue（  @ intpdfId，txtdanceid.Text）; 
 
 SqlDataReader myReader = myCommand.ExecuteReader（）; 
 
  if （myReader.Read（））
 {
 Response.ContentType = myReader [  ContentType]。ToString（）; 
 Response.BinaryWrite（（ byte  []）myReader [  strpdfurl]）; 
 
} 
 
 myReader.Close（）; 
 Response.End（）; 

我哪里错了？

解决方案

您一次传递内联参数和命令参数。你需要选择其中一个，更好的选择是传递命令参数而不是内联值。



请参阅下面修改过的sql语句，

  string  SQL =  < span class =code-string> SELECT * FROM DPSpdf WHERE intpdfId = @ intpdfId; 
 SqlCommand myCommand =  new  SqlCommand（SQL，（SqlConnection）Application.Get（  DPS））; 
 myCommand.Parameters.AddWithValue（  @ intpdfId，txtdanceid.Text）; 
 SqlDataReader myReader = myCommand.ExecuteReader（）; 
  if （myReader.Read（））
 {
 Response.ContentType = myReader [  ContentType]。ToString（）; 
 Response.BinaryWrite（（ byte  []）myReader [  strpdfurl]）; 
} 
 
 myReader.Close（）; 
 Response.End（）; 

试用此代码

 System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding（）; 
 byte [] data =（byte []）myReader [strpdfurl]; 
 System.Web.HttpResponse Response = System.Web.HttpContext.Current.Response; 
 
 Response.Charset =; 
 Response.Cache.SetCacheability（HttpCacheability.NoCache）; 
 Response.ContentType = myReader [ContentType]。ToString（）; 
 Response.AddHeader（content-disposition，attachment; filename =+Test+。pdf）; 
 Response.BinaryWrite（data）; 
 Response.Flush（）; 
 Response.End（）; 

服务器错误   '  / WebSite2'Application。 
 ExecuteReader：连接属性 未已初始化。

string SQL = "SELECT * FROM DPSpdf WHERE intpdfId='" + txtdanceid.Text + "'";
        SqlCommand myCommand = new SqlCommand(SQL, (SqlConnection)Application.Get("DPS"));
        myCommand.Parameters.AddWithValue("@intpdfId", txtdanceid.Text);

        SqlDataReader myReader = myCommand.ExecuteReader();

        if (myReader.Read())
        {
            Response.ContentType = myReader["ContentType"].ToString();
            Response.BinaryWrite((byte[])myReader["strpdfurl"]);

        }

        myReader.Close();
        Response.End();

Where i did mistake?

解决方案

Hi,

You are passing inline parameter and command parameter at a time. You need to choose one of them, better choice is passing command parameter instead of inline value.

Please see the modified sql statement below,

string SQL = "SELECT * FROM DPSpdf WHERE intpdfId=@intpdfId";
SqlCommand myCommand = new SqlCommand(SQL, (SqlConnection)Application.Get("DPS"));
myCommand.Parameters.AddWithValue("@intpdfId", txtdanceid.Text);
SqlDataReader myReader = myCommand.ExecuteReader();
if (myReader.Read())
{
   Response.ContentType = myReader["ContentType"].ToString();
   Response.BinaryWrite((byte[])myReader["strpdfurl"]);
}

myReader.Close();
Response.End();

Try this code

System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
byte[] data = (byte[])myReader["strpdfurl"];
System.Web.HttpResponse Response = System.Web.HttpContext.Current.Response;

Response.Charset = "";
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.ContentType = myReader["ContentType"].ToString();
Response.AddHeader("content-disposition", "attachment;filename=" + "Test" + ".pdf");
Response.BinaryWrite(data);
Response.Flush();
Response.End();

Server Error in '/WebSite2' Application.
ExecuteReader: Connection property has not been initialized.

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