CODEWITHSUNDEEP
c#mvvmwindows-phone-8.1icommand
Rohit
Rohit

Reputation: 552

Binding Command Not found Error

I am not using any particular library for this. I have a Listview in page and on its click I want to call a command named DemoCommand but as I bind my ViewModel to page it shows error command not found. My Xaml code is.

<Grid DataContext="{Binding OrdersObject}">
    <ListView Grid.Row="1" ItemsSource="{Binding data.orders}" SelectionChanged="ListView_SelectionChanged" ItemTemplate="{StaticResource DueOrderTemplate}" ItemContainerStyle="{StaticResource StretchItemStyle}">
        <Interactivity:Interaction.Behaviors>
            <Core:EventTriggerBehavior EventName="SelectionChanged">
                <Core:InvokeCommandAction CommandParameter="{Binding}" Command="{Binding DemoCommand}"/>
            </Core:EventTriggerBehavior>
        </Interactivity:Interaction.Behaviors>
    </ListView>
</Grid>

My binding code is

var OrdersObj = new ViewModels.OrdersVM();

            await OrdersObj.GetOrders("cancel");
            this.DataContext = OrdersObj;

And my View Model code is 

class OrdersVM
{
    public Models.DueOrderM OrdersObject { get; set; }

    async public Task<Boolean> GetOrders(string order_type)
    {
       OrdersObject=//from API
    }
    RelayCommand<Models.OOrderM> _demoCommand;

    public RelayCommand<Models.OOrderM> DemoCommand
    {
        get
        {
            if (_demoCommand == null)
            {
                _demoCommand = new RelayCommand<Models.OOrderM>((itemParam) =>
                {
                    System.Diagnostics.Debug.WriteLine(itemParam);
                });
            }
            return _demoCommand;
        }
        set { _demoCommand = value; }
    }

}

Upvotes: 0

Views: 547

Answers (2)

Rohit
Rohit

Reputation: 552

I was able to solve the problem myself after looking few examples none of which were working I got the solution myself according to which I needed to change only my Xaml code. updated code is

<ListView x:Name="lstItem" Grid.Row="1" ItemsSource="{Binding OrdersObject.data.orders}" ItemTemplate="{StaticResource DueOrderTemplate}" ItemContainerStyle="{StaticResource StretchItemStyle}">
        <Interactivity:Interaction.Behaviors>
            <Core:EventTriggerBehavior EventName="SelectionChanged">
                <Core:InvokeCommandAction CommandParameter="{Binding SelectedItem, ElementName=lstItem}" Command="{Binding DemoCommand}"/>
            </Core:EventTriggerBehavior>
        </Interactivity:Interaction.Behaviors>
    </ListView>

Important thing I noted was naming of listview in command parameter and need to assign it using x:Name then it worked else it did not work. Hope it helps someone like me.

Upvotes: 1

hdev
hdev

Reputation: 6507

  1. I would set DataContext not in 'code behind' but in XAML 

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
mc:Ignorable="d" 
DataContext="{Binding ViewModel, Source={StaticResource ViewModelLocator}}"
d:DataContext="{Binding ViewModel, Source={StaticResource ViewModelLocator}}"

  2. You set OrdersObject as DataContext to the Grid, so try RelativeSources so your Command-Binding can see the ViewModel again.

Upvotes: 0

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