Dropdown Binders

Binders for the TMP_Dropdown (TextMeshPro) component.

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DropdownValueBinder

Binds the selected index, TMP_Dropdown.value.

Interface	Description
IBinder<int>	Sets the index from the ViewModel
INumberBinder	Accepts int, float, long, double

Modes: OneWay, OneTime, OneWayToSource (TwoWay is not allowed).

[ViewModel]
public partial class LanguageViewModel
{
    [OneWayBind] private int _selectedLanguageIndex;
}

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DropdownValueSwitcherBinder

bool → one of two indices.

Modes: OneWay, OneTime.

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DropdownOptionsBinder

Binds the TMP_Dropdown option list.

Interface	Description
IBinder<List<string>>	Sets text options
IBinder<List<Sprite>>	Sets sprite options
IBinder<IEnumerable<TMP_Dropdown.OptionData>>	Sets options with the full data set
IReverseBinder<List<TMP_Dropdown.OptionData>>	Sends the current options back (OneWayToSource)

On set the old options are cleared and the new ones added; null clears the list. The selected index is kept when the new list still contains it.

Modes: OneWay, OneTime, OneWayToSource (TwoWay is not allowed).

[ViewModel]
public partial class LanguageViewModel
{
    [OneWayBind] private List<string> _languages;

    public LanguageViewModel()
    {
        _languages = new List<string> { "English", "Русский", "日本語" };
    }
}

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DropdownOptionsSwitcherBinder

bool → one of two option sets.

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DropdownOptionsByEnumMonoBinder

Fills the options with the values of the bound value's enum type. The options are rebuilt only when the type changes; null clears the list. An optional IConverter<Enum, IEnumerable<OptionData>> (for example EnumToDropdownOptionDataConverter) provides the labels; without it the value names are used.

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DropdownAlphaFadeSpeedBinder

Binds the fade speed, TMP_Dropdown.alphaFadeSpeed.

A negative value is raised to 0, NaN is logged.

Modes: OneWay, OneTime, OneWayToSource (TwoWay is not allowed).

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DropdownAlphaFadeSpeedSwitcherBinder

bool → one of two fade speeds.

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DropdownCommandBinder

Binds a command to TMP_Dropdown.onValueChanged. When an item is selected it calls command.Execute(selectedIndex).

Interface	Description
IBinder<IRelayCommand<int>>	Passes the index as int
IBinder<IRelayCommand<long>>	Passes the index as long

InteractableMode

As in ButtonCommandBinder, the reaction to CanExecute:

Mode	Behaviour
Interactable	dropdown.interactable = canExecute
Visible	gameObject.SetActive(canExecute)
None	Ignores it
Custom	Calls ICanExecuteHandler.SetCanExecute(bool)

Parameterized variants

Binder	Command	Extra parameters
DropdownCommandBinder	IRelayCommand<int> / IRelayCommand<long>	—
DropdownCommandBinder<T>	IRelayCommand<int, T>	1 parameter
DropdownCommandBinder<T1, T2>	IRelayCommand<int, T1, T2>	2 parameters
DropdownCommandBinder<T1, T2, T3>	IRelayCommand<int, T1, T2, T3>	3 parameters

The first command parameter is always the selected index.

Modes: OneWay, OneTime.

[ViewModel]
public partial class LanguageViewModel
{
    [RelayCommand]
    private void SelectLanguage(int index) { /* ... */ }
    // → IRelayCommand<int> SelectLanguageCommand
}

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DropdownToSourceMonoBinder

A MonoBinder for OneWayToSource binding of the TMP_Dropdown as a component. Inherits ComponentToSourceMonoBinder<TMP_Dropdown>.

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See also

• Slider Binders
• Button Command Binders, InteractableMode
• StarterKit overview