Sets the default file extension, which is appended to a file name if the user fails to type an extension.
public final void setDefaultExt( String value )
value
A string that represents the default file extension. The specified string can be any length, but only the first three characters are appended to the file name. The string should not contain a period. The default value for the default extension is an empty string, which causes no extension to be appended.
See the OpenFileDialog control topic for a code example using this method.
See Also getDefaultExt