Adding different Commands to elements in dynamically populated ListView










0















I have a ListView with dynamically added items. Every row in the list contains a Label, a Switch and a Button. The respective Button should only be visible when the Switch for that ViewCell is toggled. The respective Button should also have a Command that is specific to that item in the list. How can I achieve this? I am using the MVVM pattern.



<ListView HorizontalOptions="FillAndExpand" ItemsSource="Binding SomeList">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
<Label
HorizontalOptions="StartAndExpand"
Text="Binding SomePropertyFromSomeList"
VerticalOptions="Center" />
<Switch />
<Button
Command="Binding DoSomethingSpecificToThisSwitch"
IsVisible="Binding VisibleWhenThisSwitchIsToggled"
Text="Binding AlsoDependentOnWhichSwitch" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>









share|improve this question


























    0















    I have a ListView with dynamically added items. Every row in the list contains a Label, a Switch and a Button. The respective Button should only be visible when the Switch for that ViewCell is toggled. The respective Button should also have a Command that is specific to that item in the list. How can I achieve this? I am using the MVVM pattern.



    <ListView HorizontalOptions="FillAndExpand" ItemsSource="Binding SomeList">
    <ListView.ItemTemplate>
    <DataTemplate>
    <ViewCell>
    <StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
    <Label
    HorizontalOptions="StartAndExpand"
    Text="Binding SomePropertyFromSomeList"
    VerticalOptions="Center" />
    <Switch />
    <Button
    Command="Binding DoSomethingSpecificToThisSwitch"
    IsVisible="Binding VisibleWhenThisSwitchIsToggled"
    Text="Binding AlsoDependentOnWhichSwitch" />
    </StackLayout>
    </ViewCell>
    </DataTemplate>
    </ListView.ItemTemplate>
    </ListView>









    share|improve this question
























      0












      0








      0








      I have a ListView with dynamically added items. Every row in the list contains a Label, a Switch and a Button. The respective Button should only be visible when the Switch for that ViewCell is toggled. The respective Button should also have a Command that is specific to that item in the list. How can I achieve this? I am using the MVVM pattern.



      <ListView HorizontalOptions="FillAndExpand" ItemsSource="Binding SomeList">
      <ListView.ItemTemplate>
      <DataTemplate>
      <ViewCell>
      <StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
      <Label
      HorizontalOptions="StartAndExpand"
      Text="Binding SomePropertyFromSomeList"
      VerticalOptions="Center" />
      <Switch />
      <Button
      Command="Binding DoSomethingSpecificToThisSwitch"
      IsVisible="Binding VisibleWhenThisSwitchIsToggled"
      Text="Binding AlsoDependentOnWhichSwitch" />
      </StackLayout>
      </ViewCell>
      </DataTemplate>
      </ListView.ItemTemplate>
      </ListView>









      share|improve this question














      I have a ListView with dynamically added items. Every row in the list contains a Label, a Switch and a Button. The respective Button should only be visible when the Switch for that ViewCell is toggled. The respective Button should also have a Command that is specific to that item in the list. How can I achieve this? I am using the MVVM pattern.



      <ListView HorizontalOptions="FillAndExpand" ItemsSource="Binding SomeList">
      <ListView.ItemTemplate>
      <DataTemplate>
      <ViewCell>
      <StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
      <Label
      HorizontalOptions="StartAndExpand"
      Text="Binding SomePropertyFromSomeList"
      VerticalOptions="Center" />
      <Switch />
      <Button
      Command="Binding DoSomethingSpecificToThisSwitch"
      IsVisible="Binding VisibleWhenThisSwitchIsToggled"
      Text="Binding AlsoDependentOnWhichSwitch" />
      </StackLayout>
      </ViewCell>
      </DataTemplate>
      </ListView.ItemTemplate>
      </ListView>






      c# xaml xamarin.forms






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 15 '18 at 8:15









      ZebrastianZebrastian

      536




      536






















          1 Answer
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          Best way I find to tackle this, is to use a CommandParameter and decide what to do in your ViewModel based on the context of the ViewCell data.



          If you use Binding, you can bind to the whole context of the current data by selecting a . ( dot ), that way the data from the current ViewCell is passed to your ViewModel.



          Let's show how you code this...
          Your View should look like this



          <?xml version="1.0" encoding="utf-8"?>
          <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:TestCommand"
          x:Name="TestPage"
          x:Class="TestCommand.MainPage">
          <StackLayout>
          <ListView ItemsSource="Binding Persons" RowHeight="50">
          <ListView.ItemTemplate>
          <DataTemplate>
          <ViewCell>
          <StackLayout>
          <Label Text="Binding Name" />
          <Button Text="Click" Command="Binding DoCommand, Source=x:Reference TestPage" CommandParameter="Binding ." />
          </StackLayout>
          </ViewCell>
          </DataTemplate>
          </ListView.ItemTemplate>
          </ListView>
          </StackLayout>
          </ContentPage>


          Note that you need to provide a Name for your page! With that you can point to the same command in each ViewCell. But pass in the current ViewCell data with the Command Parameter.



          In your ViewModel you than can act upon the 'selected' data... and do something specific like so:



          public List<Person> Persons get; set; = new List<Person>() new Person() Name = "Glenn Versweyveld" , new Person() Name = "John Do" ;

          private Command<Person> _doCommand;
          public Command<Person> DoCommand => _doCommand ?? (_doCommand = new Command<Person>((Person obj) => HandlePerson(obj)));

          private void HandlePerson(Person obj)








          share|improve this answer























          • I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

            – Zebrastian
            Nov 15 '18 at 10:39












          • What is the BindingContext of your ContentPage?

            – Depechie
            Nov 15 '18 at 10:42











          • The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

            – Depechie
            Nov 15 '18 at 10:48











          • My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

            – Zebrastian
            Nov 15 '18 at 11:22












          • That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

            – Depechie
            Nov 15 '18 at 11:40










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          active

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          0














          Best way I find to tackle this, is to use a CommandParameter and decide what to do in your ViewModel based on the context of the ViewCell data.



          If you use Binding, you can bind to the whole context of the current data by selecting a . ( dot ), that way the data from the current ViewCell is passed to your ViewModel.



          Let's show how you code this...
          Your View should look like this



          <?xml version="1.0" encoding="utf-8"?>
          <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:TestCommand"
          x:Name="TestPage"
          x:Class="TestCommand.MainPage">
          <StackLayout>
          <ListView ItemsSource="Binding Persons" RowHeight="50">
          <ListView.ItemTemplate>
          <DataTemplate>
          <ViewCell>
          <StackLayout>
          <Label Text="Binding Name" />
          <Button Text="Click" Command="Binding DoCommand, Source=x:Reference TestPage" CommandParameter="Binding ." />
          </StackLayout>
          </ViewCell>
          </DataTemplate>
          </ListView.ItemTemplate>
          </ListView>
          </StackLayout>
          </ContentPage>


          Note that you need to provide a Name for your page! With that you can point to the same command in each ViewCell. But pass in the current ViewCell data with the Command Parameter.



          In your ViewModel you than can act upon the 'selected' data... and do something specific like so:



          public List<Person> Persons get; set; = new List<Person>() new Person() Name = "Glenn Versweyveld" , new Person() Name = "John Do" ;

          private Command<Person> _doCommand;
          public Command<Person> DoCommand => _doCommand ?? (_doCommand = new Command<Person>((Person obj) => HandlePerson(obj)));

          private void HandlePerson(Person obj)








          share|improve this answer























          • I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

            – Zebrastian
            Nov 15 '18 at 10:39












          • What is the BindingContext of your ContentPage?

            – Depechie
            Nov 15 '18 at 10:42











          • The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

            – Depechie
            Nov 15 '18 at 10:48











          • My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

            – Zebrastian
            Nov 15 '18 at 11:22












          • That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

            – Depechie
            Nov 15 '18 at 11:40















          0














          Best way I find to tackle this, is to use a CommandParameter and decide what to do in your ViewModel based on the context of the ViewCell data.



          If you use Binding, you can bind to the whole context of the current data by selecting a . ( dot ), that way the data from the current ViewCell is passed to your ViewModel.



          Let's show how you code this...
          Your View should look like this



          <?xml version="1.0" encoding="utf-8"?>
          <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:TestCommand"
          x:Name="TestPage"
          x:Class="TestCommand.MainPage">
          <StackLayout>
          <ListView ItemsSource="Binding Persons" RowHeight="50">
          <ListView.ItemTemplate>
          <DataTemplate>
          <ViewCell>
          <StackLayout>
          <Label Text="Binding Name" />
          <Button Text="Click" Command="Binding DoCommand, Source=x:Reference TestPage" CommandParameter="Binding ." />
          </StackLayout>
          </ViewCell>
          </DataTemplate>
          </ListView.ItemTemplate>
          </ListView>
          </StackLayout>
          </ContentPage>


          Note that you need to provide a Name for your page! With that you can point to the same command in each ViewCell. But pass in the current ViewCell data with the Command Parameter.



          In your ViewModel you than can act upon the 'selected' data... and do something specific like so:



          public List<Person> Persons get; set; = new List<Person>() new Person() Name = "Glenn Versweyveld" , new Person() Name = "John Do" ;

          private Command<Person> _doCommand;
          public Command<Person> DoCommand => _doCommand ?? (_doCommand = new Command<Person>((Person obj) => HandlePerson(obj)));

          private void HandlePerson(Person obj)








          share|improve this answer























          • I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

            – Zebrastian
            Nov 15 '18 at 10:39












          • What is the BindingContext of your ContentPage?

            – Depechie
            Nov 15 '18 at 10:42











          • The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

            – Depechie
            Nov 15 '18 at 10:48











          • My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

            – Zebrastian
            Nov 15 '18 at 11:22












          • That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

            – Depechie
            Nov 15 '18 at 11:40













          0












          0








          0







          Best way I find to tackle this, is to use a CommandParameter and decide what to do in your ViewModel based on the context of the ViewCell data.



          If you use Binding, you can bind to the whole context of the current data by selecting a . ( dot ), that way the data from the current ViewCell is passed to your ViewModel.



          Let's show how you code this...
          Your View should look like this



          <?xml version="1.0" encoding="utf-8"?>
          <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:TestCommand"
          x:Name="TestPage"
          x:Class="TestCommand.MainPage">
          <StackLayout>
          <ListView ItemsSource="Binding Persons" RowHeight="50">
          <ListView.ItemTemplate>
          <DataTemplate>
          <ViewCell>
          <StackLayout>
          <Label Text="Binding Name" />
          <Button Text="Click" Command="Binding DoCommand, Source=x:Reference TestPage" CommandParameter="Binding ." />
          </StackLayout>
          </ViewCell>
          </DataTemplate>
          </ListView.ItemTemplate>
          </ListView>
          </StackLayout>
          </ContentPage>


          Note that you need to provide a Name for your page! With that you can point to the same command in each ViewCell. But pass in the current ViewCell data with the Command Parameter.



          In your ViewModel you than can act upon the 'selected' data... and do something specific like so:



          public List<Person> Persons get; set; = new List<Person>() new Person() Name = "Glenn Versweyveld" , new Person() Name = "John Do" ;

          private Command<Person> _doCommand;
          public Command<Person> DoCommand => _doCommand ?? (_doCommand = new Command<Person>((Person obj) => HandlePerson(obj)));

          private void HandlePerson(Person obj)








          share|improve this answer













          Best way I find to tackle this, is to use a CommandParameter and decide what to do in your ViewModel based on the context of the ViewCell data.



          If you use Binding, you can bind to the whole context of the current data by selecting a . ( dot ), that way the data from the current ViewCell is passed to your ViewModel.



          Let's show how you code this...
          Your View should look like this



          <?xml version="1.0" encoding="utf-8"?>
          <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
          xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
          xmlns:local="clr-namespace:TestCommand"
          x:Name="TestPage"
          x:Class="TestCommand.MainPage">
          <StackLayout>
          <ListView ItemsSource="Binding Persons" RowHeight="50">
          <ListView.ItemTemplate>
          <DataTemplate>
          <ViewCell>
          <StackLayout>
          <Label Text="Binding Name" />
          <Button Text="Click" Command="Binding DoCommand, Source=x:Reference TestPage" CommandParameter="Binding ." />
          </StackLayout>
          </ViewCell>
          </DataTemplate>
          </ListView.ItemTemplate>
          </ListView>
          </StackLayout>
          </ContentPage>


          Note that you need to provide a Name for your page! With that you can point to the same command in each ViewCell. But pass in the current ViewCell data with the Command Parameter.



          In your ViewModel you than can act upon the 'selected' data... and do something specific like so:



          public List<Person> Persons get; set; = new List<Person>() new Person() Name = "Glenn Versweyveld" , new Person() Name = "John Do" ;

          private Command<Person> _doCommand;
          public Command<Person> DoCommand => _doCommand ?? (_doCommand = new Command<Person>((Person obj) => HandlePerson(obj)));

          private void HandlePerson(Person obj)









          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 15 '18 at 9:09









          DepechieDepechie

          5,1261939




          5,1261939












          • I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

            – Zebrastian
            Nov 15 '18 at 10:39












          • What is the BindingContext of your ContentPage?

            – Depechie
            Nov 15 '18 at 10:42











          • The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

            – Depechie
            Nov 15 '18 at 10:48











          • My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

            – Zebrastian
            Nov 15 '18 at 11:22












          • That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

            – Depechie
            Nov 15 '18 at 11:40

















          • I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

            – Zebrastian
            Nov 15 '18 at 10:39












          • What is the BindingContext of your ContentPage?

            – Depechie
            Nov 15 '18 at 10:42











          • The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

            – Depechie
            Nov 15 '18 at 10:48











          • My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

            – Zebrastian
            Nov 15 '18 at 11:22












          • That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

            – Depechie
            Nov 15 '18 at 11:40
















          I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

          – Zebrastian
          Nov 15 '18 at 10:39






          I'm trying to test your example, but I can't get the DoCommand binding to work. I get "Binding: 'DoCommand' property not found on 'TestCommand.MainPage', target property: 'Xamarin.Forms.Button.Command'". Do you have any idea what I'm missing?

          – Zebrastian
          Nov 15 '18 at 10:39














          What is the BindingContext of your ContentPage?

          – Depechie
          Nov 15 '18 at 10:42





          What is the BindingContext of your ContentPage?

          – Depechie
          Nov 15 '18 at 10:42













          The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

          – Depechie
          Nov 15 '18 at 10:48





          The error code at least, means that it's looking for the Command in the BindingContext of the ContentPage. But that that BindingContext ( your ViewModel ) does not contain the DoCommand public property.

          – Depechie
          Nov 15 '18 at 10:48













          My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

          – Zebrastian
          Nov 15 '18 at 11:22






          My MainPage.xaml.cs should do the BindingContext: this.BindingContext = new TestViewModel();

          – Zebrastian
          Nov 15 '18 at 11:22














          That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

          – Depechie
          Nov 15 '18 at 11:40





          That seems correct and you added the command on that TestViewModel I guess... now the error you posted states "not found on 'TestCommand.MainPage', target property". Did you just copy paste my code over your ContentPage code? Because I think the ClassName should be your test page class name and not the one I provided in this sample...

          – Depechie
          Nov 15 '18 at 11:40



















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