private async Task <StorageFile> DoPickSingleFileAsync()
{
if (_filter.Count == 0)
{
throw new InvalidOperationException("The FileTypeFilters property must have at least one file type filter specified.");
}
NativeMethods.OPENFILENAME ofn = new Pickers.FileOpenPicker.NativeMethods.OPENFILENAME();
StringBuilder sb = new StringBuilder();
foreach (string ext in _filter)
{
sb.Append("*" + ext + "\0*" + ext + "\0");
}
sb.Append("\0");
ofn.lpstrFilter = sb.ToString();
ofn.lStructSize = Marshal.SizeOf(ofn);
ofn.nMaxFile = 256;
ofn.lpstrFile = new string('\0', ofn.nMaxFile);
ofn.Flags = 0x02001000;
bool success = NativeMethods.GetOpenFileName(ref ofn);
if (success)
{
return(new StorageFile(ofn.lpstrFile));
}
return(null);
}
private async Task<StorageFile> PickSingleFileAsyncImpl()
{
NativeMethods.OPENFILENAME ofn = new Pickers.FileOpenPicker.NativeMethods.OPENFILENAME();
StringBuilder sb = new StringBuilder();
foreach(string ext in _filter)
{
sb.Append("*" + ext + "\0*" + ext + "\0");
}
sb.Append("\0");
ofn.lpstrFilter = sb.ToString();
ofn.lStructSize = Marshal.SizeOf(ofn);
ofn.nMaxFile = 256;
ofn.lpstrFile = new string('\0', ofn.nMaxFile);
ofn.Flags = 0x02001000;
bool success = NativeMethods.GetOpenFileName(ref ofn);
if(success)
{
return new StorageFile(ofn.lpstrFile);
}
return null;
}