CODEWITHSUNDEEP
xamarinxamarin.forms
maouriceg
maouriceg

Reputation: 49

How to access properties in Code Behind on a Xamarin Forms Page

I am feeling really stupid right now. I have a page with a listing of transactions. When a user selects an item on the grid, I load the properties for that selection into a details page. I am binding and properly displaying the details in XAML, But I need to access the property values in code behind to make some subsequence calls to an API. I am drawing a blank on how to achieve that here.

            <Label Grid.Column="3"
            Grid.Row="2"
            Text="{Binding Amount}" />
            <Label Grid.Column="4"
            Grid.Row="2"
            Text="{Binding Status}"
            VerticalOptions="End" />

So how would I get the value of Status and Amount in Code Behind.

Upvotes: 0

Views: 2173

Answers (2)

Junior Jiang
Junior Jiang

Reputation: 12721

Here is a sample to explain how to get content from Control.

VeggieViewModel class :

public class VeggieViewModel
{
    public string Name { get; set; }
    public string Type { get; set; }
    public string Image { get; set; }
}

Create a ViewModel with specified data :

public class ViewModel
{
    public ObservableCollection<VeggieViewModel> veggies { get; set; }
    public ViewModel()
    {
        veggies = new ObservableCollection<VeggieViewModel>();
        veggies.Add(new VeggieViewModel { Name = "Tomato", Type = "Fruit", Image = "tomato.png" });
        veggies.Add(new VeggieViewModel { Name = "Romaine Lettuce", Type = "Vegetable", Image = "lettuce.png" });
        veggies.Add(new VeggieViewModel { Name = "Zucchini", Type = "Vegetable", Image = "zucchini.png" });
    }
}

Xaml code as follow :

<ListView  x:Name="lstView" RowHeight="60" ItemSelected="lstView_ItemSelected">
    <ListView.ItemTemplate>
        <DataTemplate>
            <ViewCell>
                </StackLayout>-->
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="*"/>
                        <RowDefinition Height="*"/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>

                    <Image Grid.RowSpan="2" Grid.Column="0" Source="{Binding Image}"/>
                    <Label Grid.Row="0" Grid.Column="1" Text="{Binding Name}" FontSize="24" />
                    <Label Grid.Row="1" Grid.Column="1" Text="{Binding Type}" />
                </Grid>
            </ViewCell>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

Now in ContentPage , binding data for ListView and deal with ItemSelected method .I will get content of Name and Type ,that's the same with your want of Status and Amount .

public MainPage ()
{
    InitializeComponent();

    ViewModel viewModel = new ViewModel();

    lstView.ItemsSource = viewModel.veggies;
}

private void lstView_ItemSelected(object sender, SelectedItemChangedEventArgs e)
{
    var obj = (VeggieViewModel)e.SelectedItem;
    Console.WriteLine("-name is-" + obj.Name + "-type is-" + obj.Type);
    DisplayAlert("Show Message", "-name is-" + obj.Name + "-type is-" + obj.Type, "OK");
    // other code 
}

The effect :

enter image description here

Upvotes: 1

Dima Kravchyk
Dima Kravchyk

Reputation: 21

You can add name for label and then get property in code behind.

<Label x:Name="label" Grid.Column="4"
  Grid.Row="2"
  Text="{Binding Status}"
  VerticalOptions="End" />

var value = label.Text // get value in code behind

Also you can get value from BindingContext. You need cast you binding context in you view model type

if(BindingContext is YouViewModelType context)
{
    var value = context.Status
}

Upvotes: 1

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