Ensures that the current Twain properties are valid.
For example, if the application assigns a combination of PixelType and YResolution unsupported by scanner, the Update method restores the PixelType and YResolution value to a value supported by the scanner.
Note: Don't use this method to refresh the list of available devices, use SetDefaultParams instead.
// Try if RGB and YResolution combination is supported ImageEnView1.IO.TwainParams.PixelType.CurrentValue := 2; ImageEnView1.IO.TwainParams.YResolution.CurrentValue := 300; ImageEnView1.IO.TwainParams.Update(); if (ImageEnView1.IO.TwainParams.PixelType.CurrentValue<>2) or (ImageEnView1.IO.TwainParams.YResolution.CurrentValue<>300) then ShowMessage('error!');