getting error on picker when binding data CommunityToolkit.Mvvm

Question

 xmlns:viewModels="clr-namespace:Dev.ViewModels"
 xmlns:models="clr-namespace:Dev.Models"
 x:DataType="viewModels:LoginViewModel" 


<Picker ItemsSource="{Binding Genders,Mode=TwoWay}"
                        SelectedItem="{Binding SelectedItemGender,Mode=TwoWay}"
                        ItemDisplayBinding="{Binding PickerText}"
                        FontFamily="OpenSansSemibold"
                        VerticalOptions="CenterAndExpand" 
                        HorizontalOptions="FillAndExpand"
                        FontSize="12"/>

    public class PickerRoot
    {
        public string? PickerValue { get; set; }
        public string? PickerText { get; set; }
    }

internal partial class LoginViewModel
{
    [ObservableProperty]
    private ObservableCollection<PickerRoot> genders = new();
    [ObservableProperty]
    private PickerRoot? selectedItemGender;
    public LoginViewModel()
    {
        GetGenderList();
    }
    private void GetGenderList()
    {
        Genders.Clear();
        Genders.Add(new PickerRoot { PickerText = "Select", PickerValue = "Select" });
        Genders.Add(new PickerRoot { PickerText = "Male", PickerValue = "Male" });
        Genders.Add(new PickerRoot { PickerText = "Female", PickerValue = "Female" });
        SelectedItemGender = Genders.Where(x => x.PickerText == "Male").FirstOrDefault();
    }
}

getting error- XamlC warning XC0022: Binding could be compiled to improve runtime performance if x:DataType is specified.

 <Picker ItemsSource="{Binding Genders}"
                        x:DataType="models:PickerRoot"
                        SelectedItem="{Binding SelectedItemGender,Mode=TwoWay}"
                        ItemDisplayBinding="{Binding PickerText}"
                        TitleColor="{DynamicResource LabelPlaceHolder}" 
                        FontFamily="OpenSansSemibold"
                        VerticalOptions="CenterAndExpand" 
                        HorizontalOptions="FillAndExpand"
                        FontSize="12"/>

if i specify x:DataType then getting below error
XamlC warning XC0045: Binding: Property "Genders" not found on "Dev.Models.PickerRoot".

Answer 1

Hello,

Please modify the code like the following:

<Picker ...
<!-- x:DataType="models:PickerRoot" // remove this-->
             ItemDisplayBinding="{Binding PickerText, x:DataType = models:PickerRoot}"
>

You got this error because Genders is a property of LoginViewModel and you have set x:DataType="viewModels:LoginViewModel" in the Page. At the meantime, PickerText is a property of models:PickerRoot

Best Regards,

Wenyan Zhang

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