Client Software in C# .NET

Hi, We need to build a C# .NET desktop application. The graphical design of the application should be similar to XMBC. The application should download XML files that lists categorized files (the categories themselves are also given in XML). The application should support interactive filtering of the files according to the categories and searching by name or various other fields (all in XML). Each file might contain description, image and few more fields. The user should be able to select files for downloading. The download will download it by a given link (in the XML, per file), then it should decompress it (using command-line 7z, with password given) and save it where the user wants. The user will have to config credentials to access the server holding the files to download. In your bid, please refer to which controls you'd be using to make the UI look and work as awesome as possible. The software should also include auto-registration on a simple website, then saving the cookie given by it, and then when downloading each file, it should download it with that cookie. You can use wget/curl or something like that, they support it with cookies.