使用c＃asp.net從sql下載blob文件，並且不會在其相關查看器應用程序中顯示？

Question

我有一個顯示記錄的gridview。 網格視圖具有一個鏈接按鈕，我想使用該按鈕下載blob文件，但該文件保存在與gridview從中加載其數據的位置相同的表中。 該文件下載得非常好，但是問題是，當我打開下載的文件時，在它們相關的查看器應用程序中沒有顯示任何內容，意味着如果我下載了pdf文件，並且在下載后在Adobe Reader中打開時文件在Adobe Reader中完全打開了頁面正在顯示，但是空白，沒有數據在jpg，ppt，xlx等中顯示相同，這是我的代碼

string[] commandArgument = e.CommandArgument.ToString().Split('|');
            hfResourcesdocumentId.Value = commandArgument[0];
            hfBlobId.Value = commandArgument[1];

            if (e.CommandName == "ViewFile")
            {

                GetBlob(hfBlobId.Value);
             }



protected void GetBlob(string blobId)
    {
        string url = "https://api.truevault.com/v1/vaults/" + vaultId + "/blobs/" + blobId;
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.ContentType = "application/json";
        request.Accept = "*/*";
        request.Method = WebRequestMethods.Http.Get;
        request.Headers.Add("Authorization", "Basic " +               Convert.ToBase64String(Encoding.ASCII.GetBytes(apiKey + ":")));

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        StreamReader streamReader = new StreamReader(response.GetResponseStream());
        string html = streamReader.ReadToEnd();
        response.Close();
        streamReader.Close();
        string file = Convert.ToString(response.Headers["Content-Disposition"]);
        string[] str = file.Split('=');
        string filename = str[1];
        Byte[] bytes = Encoding.UTF8.GetBytes(html);
        Response.Buffer = true;
        Response.Charset = "";
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        Response.ContentType = "application/jpg/png/gif/pdf/ppt/xlx/docx";
        Response.AddHeader("content-disposition", "attachment;filename="+filename);
        Response.BinaryWrite(bytes);
        Response.Flush();
        Response.End();
}

Answer 1

嘗試使用BinaryReader而不是StreamReader。 然后取出線

Byte[] bytes = Encoding.UTF8.GetBytes(html);

當請求讀取BLOB時，TrueVault發送回二進制數據，沒有特殊編碼。

請參閱： StreamReader與BinaryReader？

Answer 2

protected void GetBlob(string blobId)
    {
string url = "https://api.truevault.com/v1/vaults/" + vaultId + "/blobs/" + blobId;
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.ContentType = "application/json";
        request.Accept = "*/*";
        request.Method = WebRequestMethods.Http.Get;
        request.Headers.Add("Authorization", "Basic " + Convert.ToBase64String(Encoding.ASCII.GetBytes(apiKey + ":")));

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        BinaryReader streamReader = new BinaryReader(response.GetResponseStream());
        //string html = Convert.ToString(streamReader.ReadInt32());
        const int bufferSize = 4096;
        byte[] test;
        using (var ms = new MemoryStream())
        {
            byte[] buffer = new byte[bufferSize];
            int count;
            while ((count = streamReader.Read(buffer, 0, buffer.Length)) != 0)
                ms.Write(buffer, 0, count);
            test = ms.ToArray();
        }


        string file = Convert.ToString(response.Headers["Content-Disposition"]);
        string[] str = file.Split('=');
        string filename = str[1];
        //  Byte[] bytes = streamReader.ReadBytes(int.MaxValue);
        //Byte[] bytes = Encoding.UTF8.GetBytes(html);
        Response.Buffer = true;
        Response.Charset = "";
        response.Close();
        streamReader.Close();
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        Response.ContentType = "application/jpg/png/gif/pdf/ppt/xlx/docx";
        Response.AddHeader("content-disposition", "attachment;filename=" + filename);

        Response.BinaryWrite(test);
        Response.Flush();
        Response.End();
}