When a certain Tag in a DICOM file contains single or multiple value(s), which way is better for extracting the value(s)?

[xb284524239]

use dicom_dictionary_std::tags;
use dicom_object::OpenFileOptions;

#[derive(Debug)]
enum TagData<T> {
    Single(T),
    Multiple(Vec<T>),
}

pub fn test() -> Result<(), Box<dyn std::error::Error>> {
    let p2 = r"C:\Users\paul\Downloads\DICOM\DicomImages\CT128\CT16512\1.3.46.670589.33.1.63770769847762911000001.4688155742340319805.DCM";

    let obj = OpenFileOptions::new().read_until(tags::PIXEL_DATA).open_file(_p2)?;

    // Approach 1
    let window_center = obj.element(tags::WINDOW_CENTER)?;
    println!("multiplicity: {}", window_center.value().multiplicity());
    let window_center = match window_center.value().multiplicity() {
        1 => TagData::Single(window_center.to_float64()?),
        _ => TagData::Multiple(window_center.to_multi_float64()?),
    };
    match window_center {
        TagData::Single(x) => println!("Window Center has single-value: {}", x),
        TagData::Multiple(vec) => println!("Window Center has multi-values: {:?}", vec),
    }
    
    // Approach 2
    let window_width = obj.element(tags::WINDOW_WIDTH)?.to_multi_float64()?;
    println!("Window Width: {:?}", window_width);

    Ok(())
}

1. Manually check the value of the xxx.value().multiplicity() function. If the value is 1, return T, otherwise return Vec<T>.
2. Assume that all contain multiple values and directly use to_multi_float64() or to_multi_str() or to_multi_xxx().
3. Other ways that I'm not aware of for the time being.

In the above code, I used tags::WINDOW_CENTER and tags::WINDOW_WIDTH just as examples. In real DICOM files, there are many Tags that may have a single value or multiple values.

I don't know which is the recommended way to handle it. Could you please give me some guidance? Thank you.

[xb284524239]

Well, I've found that this function can solve my doubts.
let window_level = obj.decode_pixel_data()?.window()?;