System.Windows.Forms.FileDialog is an abstract class that contains common behavior for the System.Windows.Forms.OpenFileDialog and System.Windows.Forms.SaveFileDialog classes. It is not intended to be used directly but contains common behavior for those two classes. You cannot create an instance of System.Windows.Forms.FileDialog. Although the class is declared public, you cannot inherit from it, as it contains internal abstract methods. To create a dialog box to select or save a file, use System.Windows.Forms.OpenFileDialog or System.Windows.Forms.SaveFileDialog.

System.Windows.Forms.FileDialog is a modal dialog box; therefore, when shown, it blocks the rest of the application until the user has chosen a file. When a dialog box is displayed modally, no input (keyboard or mouse click) can occur except to objects on the dialog box. The program must hide or close the dialog box (usually in response to some user action) before input to the calling program can occur.

If you want to enable users to select a folder instead of a file, use the System.Windows.Forms.FolderBrowserDialog.

Depending upon the type of application, how data associated with the application is stored, and the reason for accessing the file system, there are many possible ways in which you can create a directory path. The following table shows the techniques for creating paths dynamically.

Notice that a full path may be built up using one or more of the described techniques. For example, the Environment.GetFolderPath(System.Environment.SpecialFolder) method might be used to obtain the path to the MyDocuments folder, then an application setting may be used to add a relative subdirectory portion.

The System.IO.Path class contains static members to assist in manipulating absolute and relative path strings, whereas the System.IO.File and System.IO.Directory classes have static members that actually manipulate files and directories, respectively.