Re: Cannot write xml back to host.

07-17-2008 3:09 PM |

When you do XDocument.Load("Settings.xml"); that tells me your Settings.xml is build in your Xap, is that right?

You can always send the updated xml string back to your server through a WebService call. Have that WebService to save the xml to a file. But I don't think that Web Service can save that file back to your Xap.

The best way is to take out the settings.xml file from your Silverlight project and put it under a folder of your Web project (or your web site). You use a WebClient.downloadString method to get it over to the Silverlight side,  and use a Web Serivice call to send it back to the server if you made change.

You can by pass the isolated storage saving if you do not need it to be saved in the client disk temporarily.

code to download the file:

           WebClient wc = new WebClient();         
            wc.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted);
            wc.DownloadStringAsync(new Uri(Application.Current.Host.Source, "../YourFileFolder/Setting.xml")); // this assume your Setting.xml in under your Web Project/YourFileFolder.

void wc_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
        
            if (e.Error == null)
            {
                XDocument myXML =XDocument.Parse(e.Result);

               ...

           }

To Save your File, add a WCF Silverlight Enabled service on your Web Project

[ServiceContract(Namespace = "")]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class YourService

{

public string SaveFile(ref string filename, string filecontent)
        {
           // save the xml to Setting.xml under YourFileFolder      

         }      

 }

 Add ServiceReference to your Silverlight Project.

Add code to send your new xml back:

var ws = new YourService.YourServiceClient();ws.SaveFileCompleted += new EventHandler<YourService.SaveFileCompletedEventArgs>(ws_SaveFileCompletedCompleted);
ws.SaveFileAsync("Setting.xml", yourXmlString);

Re: Cannot write xml back to host.

07-18-2008 5:19 AM |

Hello, I think it's better to use an ASP.NET page to upload files. While the difference is not noticeable for text files, for binary files, such as videos, by using WCF, you'll have to encode the binary content to text, which will make your file 8 times larger! WCF does support stream, which uses binary transfer, unfortunately this feature is not supported in Silverlight yet. However, with ASP.NET, you naturally have access to the input stream:

 protected void Page_Load(object sender, EventArgs e)
 {
string fileName = Request.Params["filename"];
if (!string.IsNullOrEmpty(fileName))
{
Stream inputStream = Request.InputStream;
FileStream fileStream = File.Create(Server.MapPath("~") + "\\" + fileName);
byte[] fileContent = new byte[inputStream.Length];
inputStream.Read(fileContent, 0, fileContent.Length);
fileStream.Write(fileContent, 0, fileContent.Length);
fileStream.Flush();
fileStream.Close();
inputStream.Close();
//No need to respond.
Response.Clear();
Response.End();
}

To call this ASP.NET page, you use a WebClient: 

WebClient webClient = new WebClient();
webClient.OpenWriteCompleted += new OpenWriteCompletedEventHandler(webClient_OpenWriteCompleted);
webClient.OpenWriteAsync(new Uri("http://localhost:49601/UploadTestWeb/Default.aspx?filename=Settings.xml"));

void webClient_OpenWriteCompleted(object sender, OpenWriteCompletedEventArgs e)
{
Stream outputStream = e.Result;
byte[] fileContent = Encoding.UTF8.GetBytes(myXml.ToString());
outputStream.Write(fileContent, 0, fileContent.Length);
//No need to flush.
outputStream.Close();
}