Deborah's Developer MindScape

Another use of anonymous types is for processing directories or files. For example, your application needs to collect a set of files and then process them based on a subset of the file properties.

[To begin with an overview of anonymous types, start here.]

Here is an example.

In C#:

// Query the set of files
var fileTemplateQuery = from FileInfo f in 
            new DirectoryInfo(@"C:\temp") 
            .GetFiles("*.*", SearchOption.AllDirectories) 
                 where f.Extension.ToLower() == ".xml" || 
                       f.Extension.ToLower() == ".txt" 
                 select new 
                 { 
                    DateLastModified = f.LastWriteTime, 
                    Extension = f.Extension, 
                    Size = f.Length, 
                    FileName = f.Name 
                 };

foreach (var f in fileTemplateQuery.OrderBy(file =>
                                    file.DateLastModified))
    // Do whatever you need to with the files
    Debug.WriteLine(f.FileName);

In VB:

Dim fileTemplateQuery = From f As FileInfo In _
            My.Computer.FileSystem.GetDirectoryInfo("C:\temp") _
            .GetFiles("*.*", SearchOption.AllDirectories) _
                 Where f.Extension.ToLower = ".xml" OrElse _
                       f.Extension.ToLower = ".txt" _
                 Select New With _
                 { _
                    .DateLastModified = f.LastWriteTime, _
                    .Extension = f.Extension, _
                    .Size = f.Length, _
                    .FileName = f.Name _
                  }

For Each f In _
   fileTemplateQuery.OrderBy(Function(file) file.DateLastModified)
    ' Do whatever you need to with the files
    Debug.WriteLine(f.FileName)
Next

This code uses Linq to find a specific set of files. In this case, it finds all of the files in C:\temp and its subdirectories where the extension is .xml or .txt. It then uses an anonymous type to retain the set of desired file properties.

The for/each statement loops through the set of anonymous types in order by date and performs whatever operation is required to process the files.

Enjoy!