圖像不下載按鈕點擊，即放置在網格內

Question

我無法下載圖像上的按鈕點擊..我已經放置在網格按鈕下載各自的圖像..下面是我的代碼。

protected void DownloadFile(object sender, EventArgs e) 
{ 
    int id = int.Parse((sender as LinkButton).CommandArgument); 
    byte[] bytes; 
    string fileName, contentType; 
    string constr = ConfigurationManager.ConnectionStrings["sqlcon"].ConnectionString; 
    using (SqlConnection con = new SqlConnection(constr)) 
    { 
     using (SqlCommand cmd = new SqlCommand()) 
     { 
      cmd.CommandText = "select FileName,Extentions, FileContent from Documents where ID=" + id; 
      cmd.Parameters.AddWithValue("@Id", id); 
      cmd.Connection = con; 
      con.Open(); 
      using (SqlDataReader sdr = cmd.ExecuteReader()) 
      { 
       sdr.Read(); 
       bytes = (byte[])sdr["FileContent"]; 
       contentType = sdr["Extentions"].ToString(); 
       fileName = sdr["FileName"].ToString(); 
      } 
      con.Close(); 
     } 
    } 
    Response.Clear(); 
    Response.Buffer = true; 
    Response.Charset = ""; 
    Response.Cache.SetCacheability(HttpCacheability.NoCache); 
    Response.ContentType = contentType; 
    Response.AddHeader("Content-type", contentType); 
    Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName); 
    Response.BinaryWrite(bytes); 
    Response.Flush(); 
    Response.End(); 
} 

Answer 1

更改CommandText這樣：

cmd.CommandText = "select FileName,Extentions, FileContent from Documents where ID=@Id"; 

與讀者閱讀到這一點：

while(sdr.Read()) 
{ 
       bytes = (byte[])sdr["FileContent"]; 
       contentType = sdr["Extentions"].ToString(); 
       fileName = sdr["FileName"].ToString(); 
} 

編輯：爲了測試，我用下面的代碼從獲取文件我的磁盤而不是數據庫：

protected void DownloadFile(object sender, EventArgs e) 
{ 
    int id = int.Parse((sender as LinkButton).CommandArgument); 
    byte[] bytes; 
    string fileName, contentType; 

    // Test code to download 123.sql file from C:\ 
    bytes = System.IO.File.ReadAllBytes("C:\\123.sql"); 
    contentType = ".sql"; 
    fileName = "123.sql"; 
    //string constr = ConfigurationManager.ConnectionStrings["sqlcon"].ConnectionString; 
    //using (SqlConnection con = new SqlConnection(constr)) 
    //{ 
    // using (SqlCommand cmd = new SqlCommand()) 
    // { 
    //  cmd.CommandText = "select FileName,Extentions, FileContent from Documents where ID=" + id; 
    //  cmd.Parameters.AddWithValue("@Id", id); 
    //  cmd.Connection = con; 
    //  con.Open(); 
    //  using (SqlDataReader sdr = cmd.ExecuteReader()) 
    //  { 
    //   sdr.Read(); 
    //   bytes = (byte[])sdr["FileContent"]; 
    //   contentType = sdr["Extentions"].ToString(); 
    //   fileName = sdr["FileName"].ToString(); 
    //  } 
    //  con.Close(); 
    // } 
    //} 
    Response.Clear(); 
    Response.Buffer = true; 
    Response.Charset = ""; 
    Response.Cache.SetCacheability(HttpCacheability.NoCache); 
    Response.ContentType = contentType; 
    Response.AddHeader("Content-type", contentType); 
    Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName); 
    Response.BinaryWrite(bytes); 
    Response.Flush(); 
    Response.End(); 
} 

編輯2：Here是我用過的測試項目的鏈接。