如何将枚举值与SWT Combo绑定？（无需ComboBoxViewer）

Got it, let's tackle this problem. The issue here is that PojoProperties.list() is designed to bind to instance properties of an object, but Gender.values() is a static method—there's no instance property on the enum class that exposes the list of enum constants. So we can't use PojoProperties here; instead, we need to create an observable list directly from the enum values and bind that to the Combo's items.

Step 1: Polish the Gender Enum #

First, let's add a getter to your Gender enum so we can access the custom display string you defined in the constructor:

public enum Gender {
    MALE("male"), FEMALE("female");
    
    private final String displayName;
    
    Gender(String displayName) {
        this.displayName = displayName;
    }
    
    // Getter to retrieve the human-readable display string
    public String getDisplayName() {
        return displayName;
    }
}

Step 2: Create an Observable List from Enum Values #

Use JFace Databinding's ObservableLists utility to turn the static enum array into an observable list:

import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.ObservableLists;
import java.util.Arrays;

// Create an observable list containing all Gender enum constants
IObservableList<Gender> genderList = ObservableLists.observableList(Arrays.asList(Gender.values()));

Step 3: Bind the Observable List to the Combo #

Now, use a DataBindingContext to link this list to your Combo's items property. We'll add a converter to map each enum instance to its display string (so the Combo shows "male"/"female" instead of raw enum names):

import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.conversion.IConverter;
import org.eclipse.jface.databinding.swt.WidgetProperties;

DataBindingContext dbc = new DataBindingContext();

// Bind the enum list to the Combo's items
dbc.bindList(
    WidgetProperties.items().observe(combo), // Target: Combo's items property
    genderList, // Model: Our observable enum list
    null, // No model-to-target update strategy (enum values are static)
    // Converter to turn Gender enum into display text
    new IConverter<Object, String>() {
        @Override
        public String convert(Object fromObject) {
            if (fromObject instanceof Gender) {
                return ((Gender) fromObject).getDisplayName();
            }
            return fromObject != null ? fromObject.toString() : "";
        }
    }
);

Step 4: Keep Your Existing Selection Binding #

Your original code to bind the Combo's selection to the Person's gender property works perfectly here—since the Combo's selected item will be the actual Gender enum instance, it matches the model's type:

IObservableValue<?> observeWidget = WidgetProperties.selection().observe(combo);
IObservableValue<?> observeModel = PojoProperties.value(Person.class, "gender").observe(person);
dbc.bindValue(observeWidget, observeModel);

Quick Notes #

• Since enum constants are fixed, the genderList won't change during runtime—no need to handle dynamic updates. If you ever needed a mutable enum list (uncommon), use WritableList instead.
• If you don't need custom display text and are okay with showing "MALE"/"FEMALE" in the Combo, you can skip the converter entirely—just bind the list directly to the Combo's items.

内容的提问来源于stack exchange，提问作者Shramik