Member in Font

Maker PDF 417 in Font Member

BaseAddress Credentials Headers QueryString ResponseHeaders DownloadData DownloadFile OpenRead OpenWrite UploadData UploadFile UploadValues

The base URI for requests made by a WebClient The network credentials used for authentication The collection of header name-value pairs The collection of query name-value pairs The collection of header name-value pairs from a response Downloads data from a URI Downloads data from a URI to a local file Opens a stream for data download Opens a stream for data upload Uploads a data buffer Uploads a local file to a URI Uploads a name-value collection to a URI

When using the methods of the WebClient class, you must provide a set of credentials that have permission to access the target Document Library. If these credentials will represent the current user, you can utilize the CredentialCache object to return the DefaultCredentials property. The DefaultCredentials property always represents the system credentials for the current security context. Once the Credentials property of the WebClient is set, you must build the source URI and the destination filename to where the document will be downloaded. After the URI of the document is known, downloading it to the local file system is as easy as calling the DownloadFile method. Listing 2-4 shows an example function in C# that downloads from a given source to the desktop. Listing 2-4. Downloading Documents from a Library private void Download_Click(string strSourceFileURL) { try { //Build the destination path string strDesktop = System.Environment.GetFolderPath(Environment.SpecialFolder.Desktop); string strDestinationFilePath = strDesktop + "\\" + strSourceFileURL.Substring(strSourceFileURL.LastIndexOf("/")+1); //Download file WebClient objWebClient = new WebClient(); objWebClient.Credentials = CredentialCache.DefaultCredentials; objWebClient.DownloadFile(strSourceFileURL, strDestinationFilePath); MessageBox.Show("File downloaded to your desktop."); } catch (Exception x) { MessageBox.Show(x.Message); } } Uploading files to a Document Library is nearly as easy as downloading. The difference is that you must open the local file and create a byte array. Once the byte array is created, it may be uploaded using the UploadData method of the WebClient. Listing 2-5 shows an example of uploading a file selected using a common dialog to a target Document Library specified in the code.

Listing 2-5. Uploading Documents to a Library if(diaOpen.ShowDialog() == DialogResult.OK) { try { //Load File into a byte array FileStream objStream = new FileStream( diaOpen.FileName, FileMode.Open, FileAccess.Read); BinaryReader objReader = new BinaryReader(objStream); byte [] arrFileBytes = objReader.ReadBytes((int)objStream.Length); objReader.Close(); objStream.Close(); //Upload file string strTarget = "http://spspdc/sites/Test/Shared%20Documents/"; string strDestination = strTarget + diaOpen.FileName.Substring(diaOpen.FileName.LastIndexOf("\\")+1); WebClient objWebClient = new WebClient(); objWebClient.Credentials = CredentialCache.DefaultCredentials; objWebClient.UploadData(strDestination,"PUT",arrFileBytes); MessageBox.Show("Document uploaded."); } catch (Exception x) { MessageBox.Show(x.Message); } }

I showed earlier that it is possible to access the metadata for any document if you know the document GUID. Using the GUID, you can access the MetaInfo BLOB in the Docs table and download it. I noted, however, that modifying the MetaInfo field was not a good idea. In fact, modifying the MetaInfo field won t really accomplish anything because the actual metadata for a document is stored in the document itself. The MetaInfo field is simply a copy of the document metadata. You can prove to yourself that the metadata is actually stored in the document by downloading a document from a library using the technique described earlier and then examining the document properties. Custom fields that you add to a Document Library are shown under the Custom tab of the Properties dialog. Figure 2-1 shows the properties for a document I downloaded from a Document Library with some custom fields defined.

If you are interested in examining and modifying the properties of documents in WSS libraries, then you will need to make use of the Lists web service. The Lists web service provides methods you can use to access any list in WSS along with the items and fields it contains. Using the Lists service is not trivial, but it does offer a significant amount of control over list schema and data. In fact, we briefly used the Lists service through JavaScript in 1 to export tasks from a list to Microsoft Outlook. In this section, I ll look at the Lists service in more detail and utilize it with projects in Visual Studio .NET. In order to get started using the Lists service in Visual Studio .NET, you must set a web reference to the Lists service in a project. Setting the web reference is done in the standard way by selecting Project Add Web Reference from Visual Studio .NET. The only difference is that a Lists web service is associated with each individual WSS site. Therefore, you must set the reference using the specific URL of the site you want to manipulate. The form of the web reference is shown in the following code: http://Server_Name/Site_Path/_vti_bin/Lists.asmx WSDL When you enter the URL for the web reference, you will see the complete interface definition for the Lists web service. You can then give the web reference a name and click the Add Reference button. Table 2-3 lists all of the methods of the Lists web service.