protected override void OnTypeChange(IFileDialog dialog)
{
var filterData = FilterData.CreateFromFilter(Filter);
dialog.GetFileTypeIndex(out var index);
var entry = filterData.EntryAt(index);
var ext = entry.IsAnyFilter() ? DefaultExt : entry.Extensions.FirstOrDefault();
if (!string.IsNullOrEmpty(ext))
{
if (ext.StartsWith(".", StringComparison.CurrentCulture))
{
ext = ext.Substring(1);
}
else if (ext.Length == 0)
{
ext = null;
}
dialog.SetDefaultExtension(ext);
}
// Resetting the name is required at this point.
dialog.GetFileName(out var fileName);
if (string.IsNullOrEmpty(fileName))
{
fileName = FileName;
}
var fileNameWihtoutExtension = Path.GetFileNameWithoutExtension(fileName);
dialog.SetFileName($"{fileNameWihtoutExtension}.{ext}");
}