我正在尝试将 XML 文件的内容从手持设备（Compact Framework/Windows CE）发送到我的服务器应用程序中的 Web API 方法，如下所示（客户端代码）：
public static string SendXMLFile(string xmlFilepath, string uri, int timeout)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
request.KeepAlive = false;
request.ProtocolVersion = HttpVersion.Version10;
request.Method = "POST";
StringBuilder sb = new StringBuilder();
using (StreamReader sr = new StreamReader(xmlFilepath))
{
String line;
while ((line = sr.ReadLine()) != null)
{
// test to see if it's finding any lines
//MessageBox.Show(line); <= works fine
sb.AppendLine(line);
}
byte[] postBytes = Encoding.UTF8.GetBytes(sb.ToString());
if (timeout < 0)
{
request.ReadWriteTimeout = timeout;
request.Timeout = timeout;
}
request.ContentLength = postBytes.Length;
request.KeepAlive = false;
request.ContentType = "application/xml";
try
{
Stream requestStream = request.GetRequestStream();
requestStream.Write(postBytes, 0, postBytes.Length);
requestStream.Close();
using (var response = (HttpWebResponse)request.GetResponse())
{
return response.ToString();
}
}
catch (Exception ex)
{
MessageBox.Show("SendXMLFile exception " + ex.Message);
request.Abort();
return string.Empty;
}
}
}
正如您在注释掉的代码中看到的（“<= 工作正常”），我已经对其进行了测试，并且我想要的数据正在添加到 StringBuilder。没有抛出异常（我没有看到“SendXMLFile 异常”）。
但是，当调用相应的服务器代码时：
[Route("api/DeliveryItems/PostArgsAndXMLFileAsStr")]
public async void PostArgsAndXMLFileAsStr([FromBody] string stringifiedXML, string serialNum, string siteNum)
{
string beginningInvoiceNum = string.Empty;
string endingInvoiceNum = string.Empty;
XDocument doc = XDocument.Parse(stringifiedXML);
...“serialNum”和“siteNum”参数符合预期（包含有效的预期值），但正文（stringifiedXML）为空。为什么？
更新
我也在客户端中添加了这个：
request.ContentLength = postBytes.Length;
// Did the sb get into the byte array?
MessageBox.Show(request.ContentLength.ToString());
...并且字节数组确实有数据，因为它向我显示“112”（XML 文件非常小）。
更新 2
现在我添加了另一个调试消息：
try
{
Stream requestStream = request.GetRequestStream();
// now test this:
MessageBox.Show(string.Format("requestStream length is {0}", requestStream.Length.ToString()));
requestStream.Write(postBytes, 0, postBytes.Length);
requestStream.Close();
using (var response = (HttpWebResponse)request.GetResponse())
{
return response.ToString();
}
}
catch (Exception ex)
{
MessageBox.Show("SendXMLFile exception " + ex.Message);
request.Abort();
return string.Empty;
}
...而且我什至没有看到“requestStream length is”消息；相反，我看到了“SendXMLFileException NotSupportedException”......？？？
更新 3
我想这是山楂效应或类似的一个例子。一旦我注释掉了那个调试 (MessageBox.Show()) 语句，我就会回到服务器应用程序中，但是 [FromBody] val 为空。
然后客户端收到消息“无法从传输连接中读取数据”
更新 4
stringifiedXML 在这里仍然为空：
public async void PostArgsAndXMLFileAsStr([FromBody] string stringifiedXML, string serialNum, string siteNum)
{
string beginningInvoiceNum = string.Empty;
string endingInvoiceNum = string.Empty;
XDocument doc = XDocument.Parse(stringifiedXML);
...即使在我修改了客户端中的代码之后，对这个问题的回应如下：
public static string SendXMLFile(string xmlFilepath, string uri)
{
MessageBox.Show(string.Format("In SendXMLFile() - xmlFilepath == {0}, uri == {1}", xmlFilepath, uri));
string strData = GetDataFromXMLFile();
HttpWebRequest request = CreateRequest(uri, HttpMethods.POST, strData, "application/xml");
request.KeepAlive = false;
request.ProtocolVersion = HttpVersion.Version10;
try
{
using (var response = (HttpWebResponse)request.GetResponse())
{
return response.GetResponseStream().ToString();
}
}
catch (Exception ex)
{
MessageBox.Show("SendXMLFile exception " + ex.Message);
request.Abort();
return string.Empty;
}
}
private static string GetDataFromXMLFile()
{
// test data - if it works, get the (same, for now) data from the file
return @"<?xml version=1.0?><LocateAndLaunch><Tasks></Tasks><Locations></Locations></LocateAndLaunch>"; //had to remove "s from version num
}
// Based on code from Andy Wiggly (the owner of Wiggly Field in Chicago and the Wiggly chewing gum company?)
public static HttpWebRequest CreateRequest(string uri, HttpMethods method, string data, string contentType)
{
WebRequest request = HttpWebRequest.Create(uri);
request.Method = Enum.ToObject(typeof(HttpMethods), method).ToString();
request.ContentType = contentType;
((HttpWebRequest)request).Accept = contentType;
if (method != HttpMethods.GET && method != HttpMethods.DELETE)
{
Encoding encoding = Encoding.UTF8;
request.ContentLength = encoding.GetByteCount(data);
request.ContentType = contentType;
request.GetRequestStream().Write(
encoding.GetBytes(data), 0, (int)request.ContentLength);
request.GetRequestStream().Close();
}
else
{
// If we're doing a GET or DELETE don't bother with this
request.ContentLength = 0;
}
// Finally, return the newly created request to the caller.
return request as HttpWebRequest;
}
注意：我不知道这是否只是关闭服务器的误导性副作用，但我随后在客户端/手持应用程序中看到了这个错误消息：
""System.Net.ProtocolVi..." "提交请求后无法执行此操作。"
更新 5
对于那些想要堆栈跟踪的人，&c：
serNum 和 siteNum 是连接到 uri 中的简单值，如下所示：
string uri = string.Format("http://192.168.125.50:28642/api/FileTransfer/GetHHSetupUpdate?serialNum={0}&clientVersion={1}", serNum, clientVer);
我试图像这样获得堆栈跟踪：
catch (Exception ex)
{
MessageBox.Show(string.Format("Msg = {0}; StackTrace = {1)", ex.Message, ex.StackTrace));
request.Abort();
return string.Empty;
}
...但现在我只看到“提交请求后无法执行此操作。”
更新 6
我将方法签名更改为：
public static HttpWebResponse SendXMLFile(string xmlFilepath, string uri)
...以及相应的代码：
try
{
using (var response = (HttpWebResponse)request.GetResponse())
{
return response;
}
}
catch (Exception ex)
{
MessageBox.Show(string.Format("Msg = {0}; StackTrace = {1)", ex.Message, ex.StackTrace));
request.Abort();
return null;
}
...但它没有任何区别（而且我没有看到“StackTrave =”消息，所以它一定是失败的 erstwheres）
更新 7
我在里面放了两个调试字符串：
0)
public static HttpWebRequest CreateRequestNoCredentials(string uri, HttpMethods method, string data, string contentType)
{
//test:
MessageBox.Show(string.Format("In CreateRequestNoCredentials(); data passed in = {0}", data));
1) 在 SendXMLFile() 中：
//test:
MessageBox.Show(string.Format("After calling CreateRequestNoCredentials(), request contentLen = {0}, headers = {1}, requestUri = {2}",
request.ContentLength, request.Headers, request.RequestUri));
...我看到了这个：
...但是在第二个有机会向我展示血淋淋的细节之前，服务器收到 null 正文值，因此崩溃，然后客户端发出相同的旧“此操作无法在之后执行”请求已提交”投诉。
更新 8
针对建议，“我怀疑如果您在 CreateRequest 调用之后删除 KeepAlive 和 ProtocolVersion 的设置，异常就会消失。 ”，我从这里更改了我的代码：
HttpWebRequest request = CreateRequestNoCredentials(uri, HttpMethods.POST, strData, "application/xml");
//test:
MessageBox.Show(string.Format("After calling CreateRequestNoCredentials(), request contentLen = {0}, headers = {1}, requestUri = {2}",
request.ContentLength, request.Headers, request.RequestUri));
request.KeepAlive = false;
request.ProtocolVersion = HttpVersion.Version10;
public static HttpWebRequest CreateRequestNoCredentials(string uri, HttpMethods method, string data, string contentType)
{
//test:
MessageBox.Show(string.Format("In CreateRequestNoCredentials(); data passed in = {0}", data));
WebRequest request = HttpWebRequest.Create(uri);
request.Method = Enum.ToObject(typeof(HttpMethods), method).ToString();
request.ContentType = contentType;
((HttpWebRequest)request).Accept = contentType;
if (method != HttpMethods.GET && method != HttpMethods.DELETE)
{
Encoding encoding = Encoding.UTF8;
request.ContentLength = encoding.GetByteCount(data);
request.ContentType = contentType;
request.GetRequestStream().Write(
encoding.GetBytes(data), 0, (int)request.ContentLength);
request.GetRequestStream().Close();
}
else
{
// If we're doing a GET or DELETE don't bother with this
request.ContentLength = 0;
}
// Finally, return the newly created request to the caller.
return request as HttpWebRequest;
}
...对此：
HttpWebRequest request = CreateRequestNoCredentials(uri, HttpMethods.POST, strData, "application/xml");
//test:
MessageBox.Show(string.Format("After calling CreateRequestNoCredentials(), request contentLen = {0}, headers = {1}, requestUri = {2}",
request.ContentLength, request.Headers, request.RequestUri));
public static HttpWebRequest CreateRequestNoCredentials(string uri, HttpMethods method, string data, string contentType)
{
//test:
MessageBox.Show(string.Format("In CreateRequestNoCredentials(); data passed in = {0}", data));
WebRequest request = HttpWebRequest.Create(uri);
request.Method = Enum.ToObject(typeof(HttpMethods), method).ToString();
request.ContentType = contentType;
((HttpWebRequest)request).Accept = contentType;
// moved from elsewhere to here:
((HttpWebRequest)request).KeepAlive = false;
((HttpWebRequest)request).ProtocolVersion = HttpVersion.Version10;
if (method != HttpMethods.GET && method != HttpMethods.DELETE)
{
Encoding encoding = Encoding.UTF8;
request.ContentLength = encoding.GetByteCount(data);
request.ContentType = contentType;
request.GetRequestStream().Write(
encoding.GetBytes(data), 0, (int)request.ContentLength);
request.GetRequestStream().Close();
}
else
{
// If we're doing a GET or DELETE don't bother with this
request.ContentLength = 0;
}
// Finally, return the newly created request to the caller.
return request as HttpWebRequest;
}
...但我仍然得到相同的错误消息（“提交请求后无法执行此操作”），并且 stringifiedXML 在到达服务器时仍然为空。
更新 9
这是我通过 Fiddler 2 发送我理解的内容时得到的结果（如果您没有视觉超能力，请右键单击图像并在新选项卡中打开）：
...但我不知道我在看什么...它有用吗？它失败了吗？“body == 0”列让我暂停/让我认为它失败了，但“204”似乎意味着“服务器成功处理了请求，但没有返回任何内容”......
更新 10
这是修复 uri 后的 Fiddler 尖叫声，我确实到达了服务器应用程序中的断点，并发送了良好的数据：
更新 11
通过更改此代码：
string strData = sb.ToString();
HttpWebRequest request = CreateRequestNoCredentials(uri, HttpMethods.POST, strData, "application/xml");
...对此：
string strData = @sb.ToString(); // GetDataFromXMLFile();
string body = String.Format("\"{0}\"", strData);
HttpWebRequest request = CreateRequestNoCredentials(uri, HttpMethods.POST, body, "application/json");
...我现在在 stringifiedXML 中得到这个：“
...所以我现在得到：“ System.Xml.XmlException 未由用户代码 HResult=-2146232000 处理消息 = 文件意外结束。第 1 行，第 15 位... ”
反正就是进步了。。。
更新 12
根据 Fiddle 中作为“请求正文”传递的字符串的确切组成/格式，结果完全不同。
以此作为请求正文：
<?xml version="1.0"?><LocateAndLaunch><Tasks></Tasks><Locations></Locations></LocateAndLaunch>
...stringifiedXML 为空
以此作为请求正文：
"<?xml version=1.0?><LocateAndLaunch><Tasks></Tasks><Locations></Locations></LocateAndLaunch>"
...stringifiedXML 完全相同 ("")
...但有一个例外：
System.Xml.XmlException 未被用户代码处理 HResult=-2146232000 Message='1.0' 是一个意外的标记。预期的标记是 '"' 或 '''。第 1 行，位置 15。Source=System.Xml LineNumber=1 LinePosition=15 SourceUri="" StackTrace: at System.Xml.XmlTextReaderImpl.Throw(Exception e) at System。 Xml.XmlTextReaderImpl.Throw(String res, String[] args) 在 System.Xml.XmlTextReaderImpl.ThrowUnexpectedToken(String expectedToken1, String expectedToken2) 在 System.Xml.XmlTextReaderImpl.ParseXmlDeclaration(Boolean isTextDecl) 在 System.Xml.XmlTextReaderImpl.Read( ）在 System.Xml.Linq.XDocument.Parse（字符串文本，LoadOptions 选项）在 System.Xml.Linq.XDocument 的 System.Xml.Linq.XDocument.Load（XmlReader 阅读器，LoadOptions 选项）。
以此作为请求正文：
"<?xml version="1.0"?><LocateAndLaunch><Tasks></Tasks><Locations></Locations></LocateAndLaunch>"
...stringifiedXML 是“
倒数第二个，以此作为请求正文：
"<?xml version=\"1.0\"?><LocateAndLaunch><Tasks></Tasks><Locations></Locations></LocateAndLaunch>"
...stringifiedXML 是完全一样的东西 ("")
...但我得到了这个例外：
System.InvalidOperationException 未被用户代码处理 HResult=-2146233079 Message=Sequence 不包含任何元素 Source=System.Core StackTrace: at System.Linq.Enumerable.First[TSource](IEnumerable`1 source) at HandheldServer.Controllers.DeliveryItemsController.d__2 c:\HandheldServer\HandheldServer\Controllers\DeliveryItemsController.cs 中的 .MoveNext()：第 109 行 InnerException：
最后，如果我通过这个，在角度内使用（尽管是虚假的）vals：
"<?xml version=\"1.0\"?><LocateAndLaunch><Tasks>Some Task</Tasks><Locations>Some Location</Locations></LocateAndLaunch>"
...我仍然得到“序列不包含任何元素”
这种方法比Rachel Canning还要挑剔！它想要什么——啤酒里有鸡蛋？！？
更新 13
使用此代码：
public async void PostArgsAndXMLFileAsStr([FromBody] string stringifiedXML, string serialNum, string siteNum)
{
XDocument doc = XDocument.Parse(await Request.Content.ReadAsStringAsync());
...或这个：
. . .XDocument doc = XDocument.Load(await Request.Content.ReadAsStreamAsync());
...这作为传入的 stringifiedXML：
“一些任务一些位置”
...我收到异常： “System.Xml.XmlException 未被用户代码 HResult=-2146232000 处理=缺少根元素。”
使用此代码（相同的 stringifiedXML）：
XDocument doc = XDocument.Parse(stringifiedXML);
...我得到，“ System.InvalidOperationException 未由用户代码 HResult=-2146233079 处理消息=序列不包含元素 Source=System.Core StackTrace: at System.Linq.Enumerable.First[TSource](IEnumerable`1 source) at HandheldServer.Controllers.DeliveryItemsController.d__2.MoveNext() 在 c:\HandheldServer\HandheldServer \Controllers\DeliveryItemsController.cs:line 109 InnerException:"
IOW，根据我解析传入字符串的方式，我得到“缺少根元素”或“序列不包含元素”
什么Deuce McAlistair MacLean Virginia Weeper？！？“ <LocateAndLaunch>”不是根元素吗？不是“某些任务”和“某些位置”元素吗？