Xamarin Android請求服務器不是建立而是獲得異常？

Question

MainActivity.cs

protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 

     // Set our view from the "main" layout resource 
     SetContentView(Resource.Layout.Main); 

     Button button = FindViewById<Button>(Resource.Id.Browse); 
     button.Click += BrowseButtonOnClick; 
    } 

    void BrowseButtonOnClick(object sender, EventArgs eventArs) 
    { 
     Intent = new Intent(); 
     Intent.SetType("image/*"); 
     Intent data = Intent.SetAction(Intent.ActionGetContent); 

     try 
     { 
      StartActivityForResult(Intent.CreateChooser(Intent, "Select Picture"), PickImageId); 
     } 
     catch (ActivityNotFoundException ex) 
     { 
      Toast.MakeText(this, "Please install a File Manager.", ToastLength.Long).Show(); 
     } 
     catch (Exception ex) 
     { 
      Toast.MakeText(this, "Error occured ", ToastLength.Long).Show(); 
     } 
    } 

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data) 
    { 
     if ((requestCode == PickImageId) && (resultCode == Result.Ok) && (data != null)) 
     { 
      UploadFile(data); 

     } 
    } 

    void UploadFile(Intent data) 
    { 
     ICursor cursor = null; 

     try 
     { 
      Button upButton = FindViewById<Button>(Resource.Id.Upload); 

      // assuming image 
      var docID = DocumentsContract.GetDocumentId(data.Data); 
      var id = docID.Split(':')[1]; 
      var whereSelect = MediaStore.Images.ImageColumns.Id + "=?"; 
      var projections = new string[] { MediaStore.Images.ImageColumns.Data }; 
      // Try internal storage first 
      cursor = ContentResolver.Query(MediaStore.Images.Media.InternalContentUri, projections, whereSelect, new string[] { id }, null); 
      if (cursor.Count == 0) 
      { 
       // not found on internal storage, try external storage 
       cursor = ContentResolver.Query(MediaStore.Images.Media.ExternalContentUri, projections, whereSelect, new string[] { id }, null); 
      } 
      var colData = cursor.GetColumnIndexOrThrow(MediaStore.Images.ImageColumns.Data); 
      cursor.MoveToFirst(); 
      var fullPathToImage = cursor.GetString(colData); 
      string fpti = cursor.GetString(colData); 

      //Toast.MakeText(this, fullPathToImage, ToastLength.Long).Show(); 

      // Log.Info("MediaPath", fullPathToImage); 

      //var client = new HttpClient(); 
      //Android.Net.Uri uri = data.Data; 

      ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
      FileInputStream fis = new FileInputStream(new File(fullPathToImage)); //uri.Path 
      byte[] buf = new byte[1024]; 
      int n; 
      while (-1 != (n = fis.Read(buf))) 
       baos.Write(buf, 0, n); 

      byte[] vBytes = baos.ToByteArray(); 

      ByteArrayContent byteContent = new ByteArrayContent(vBytes); 
      //var UploadServiceBaseAddress = "http://192.168.3.157:81/Values/UploadFile?file="; 
      //StringContent stringContent = new StringContent(UploadServiceBaseAddress, System.Text.Encoding.UTF8); 
      string base64 = Convert.ToBase64String(vBytes); 

      string strb64 = Convert.ToString(base64); 



      upButton.Click += (sender, args) => 
      { 
       ProgressDialog progressDialog = new ProgressDialog(this); 
       progressDialog.SetTitle("Please wait..."); 
       progressDialog.SetCancelable(false); 

       Task.Run(async() => 
       { 
        try 
        { 
         RunOnUiThread(() => 
         { 
          progressDialog.Show(); 

         }); 


         string dataUsed = await SendReceiveTest.Test(strb64); 

         string me = "Uploading..."; 
         Toast.MakeText(this, me, ToastLength.Long).Show(); 

         RunOnUiThread(() => 
         { 

         progressDialog.Dismiss(); 

         }); 

         string msg = "Upload Completed"; 
         Toast.MakeText(this, msg, ToastLength.Long).Show(); 
         Toast.MakeText(this, dataUsed, ToastLength.Long).Show(); 

        } 

        catch (Exception ex) 
        { 
         Log.Error("MediaPath", ex.Message); 
        } 


       }); 



      }; 
     } 
     catch (Exception ex) 
     { 
      Log.Error("MediaPath", ex.Message); 
     } 
     finally 
     { 
      cursor?.Close(); 
      cursor?.Dispose(); 
     } 
    } 

} 

}

SendReceiveTest.cs

public static async Task<string> Test(string data) 
     { 
      try 
      { 
       using (var client = new HttpClient()) 
       { 

        var uri = $"http://192.168.3.157:81/Values/UploadFile?file={data}"; 
        var response = await client.GetAsync(uri); 
        var stringData = await response.Content.ReadAsStringAsync(); 
        //Context c = null; 
        //Toast.MakeText(c, stringData, ToastLength.Long).Show(); 
        return stringData; 
       } 
      } 
      catch (Exception ex) 
      { 
       Log.Error("MediaPath", ex.Message); 

      } 
      return null; 

在異常前

{System.Net.Http.HttpRequestException: An error occurred while sending the request ---> System.Net.WebException: Error getting response stream (ReadDone2): ReceiveFailure ---> System.Exception: at System.Net.WebConnection.HandleError (System.Net.WebExceptionStatus st, System.Exception e, System.String where) [0x00000] in <a547bd0d78184f26ab08d022f013c1e1>:0 
    at System.Net.WebConnection.ReadDone (System.IAsyncResult result) [0x00000] in <a547bd0d78184f26ab08d022f013c1e1>:0 
    at System.Net.Sockets.SocketAsyncResult+<>c__DisplayClass27_0.<Complete>b__0 (System.Object _) [0x00000] in <a547bd0d78184f26ab08d022f013c1e1>:0 
    at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Threading.ThreadPoolWorkQueue.Dispatch() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Net.WebConnection.HandleError (System.Net.WebExceptionStatus st, System.Exception e, System.String where) [0x0003b] in <a547bd0d78184f26ab08d022f013c1e1>:0 
    --- End of inner exception stack trace --- 
    at System.Net.HttpWebRequest.EndGetResponse (System.IAsyncResult asyncResult) [0x00058] in <a547bd0d78184f26ab08d022f013c1e1>:0 
    at System.Threading.Tasks.TaskFactory`1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func`2[T,TResult] endFunction, System.Action`1[T] endAction, System.Threading.Tasks.Task`1[TResult] promise, System.Boolean requiresSynchronization) [0x0000f] in <3fd174ff54b146228c505f23cf75ce71>:0 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext() [0x003e6] in <b696532a7c264e5e866cb15a1b40a4a4>:0 
    --- End of inner exception stack trace --- 
    at System.Net.Http.HttpClientHandler+<SendAsync>d__63.MoveNext() [0x00449] in <b696532a7c264e5e866cb15a1b40a4a4>:0 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Net.Http.HttpClient+<SendAsyncWorker>d__49.MoveNext() [0x000ca] in <b696532a7c264e5e866cb15a1b40a4a4>:0 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult() [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0 
    at XAFileUpload.SendReceiveTest+<Test>d__0.MoveNext() [0x00066] in C:\Users\sandeepsubbiahs\Documents\Visual Studio 2017\Projects\Xamarin\XAFileUpload\XAFileUpload\SendReceiveTest.cs:28 } 

在Ex.Message

"An error occurred while sending the request" 

在內部異常

內部狀態：System.Net.WebExceptionInternalStatus.RequestFatal

狀態：System.Net.WebExceptionStatus。 ReceiveFailure

我有一個2按鈕（瀏覽，上傳），通過點擊第一個按鈕瀏覽它將搭載由Xamarin Android模擬器的圖片，然後單擊第二個按鈕上傳它發送的圖片作爲base64string到服務器通過使用SendReceiveTest後類和它的方法測試（）但發送請求到服務器時發生異常，並在上面提到。

Answer 1

使用POST請求，而不是Get請求，你最更改後端API接收POST請求

using (var client = new HttpClient()) 
     { 

      string jsonData = @"'file':'{0}'"; 
      jsonData = string.Format(jsonData, data); 

      var content = new StringContent(jsonData, Encoding.UTF8, "application/json"); 

      var uri = $"http://192.168.3.157:81/Values/UploadFile"; 
      var response = await client.PostAsync(uri, content); 
      var stringData = await response.Content.ReadAsStringAsync(); 
     } 

轉換圖像base64string的

Answer 2

這一翻譯，我們可以把它就像在使用Web客戶端

using (WebClient client = new WebClient()) 
    { 
      client.UploadFile(address, fullPathToImage); 

    }