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in Technique[技术] by (71.8m points)

c# - WPF button in ListView can not see command in ViewModel

<StackPanel>
        <!--<Button Command="{Binding GetOddsCommand}" CommandParameter="{Binding}" />-->

    <ListView 
        ItemsSource="{Binding Links}"
        >
        <ListView.ItemTemplate>
            <DataTemplate>
                <Border>
                    <Button Command="{Binding GetOddsCommand}" CommandParameter="{Binding}">
                        <TextBlock >
                        <Hyperlink NavigateUri="http://www.onet.pl" >
                            <TextBlock Text="{Binding}" />
                        </Hyperlink>
                    </TextBlock>
                    </Button>
                </Border>
            </DataTemplate>
        </ListView.ItemTemplate>

I have MVVM application. In viewmodel I have GetOddsCommand:

public ICommand GetOddsCommand
{
    get
    {
        if (_getOddsCommand == null)
            _getOddsCommand = new RelayCommand(param => GetOdds());
        return _getOddsCommand;
    }
}

private void GetOdds()
{

}

When I uncomment first button placed in StackPanel command works good. Debugger step into get and then when I click command Debugger step into GetOdds method. But it doesn't work in second button which is in the ListView. Looks like second button cannot see GetOddsCommand, but I don't understand why

Thanks

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by (71.8m points)

Putting a button and inside it a Hyperlink doesn't make much sense... What do you expect to happen when you click on the hyperlink?
Anyways, the following code will cause your command to be called:

<ListView ItemsSource="{Binding Links}" x:Name="ListView1">
        <ListView.ItemTemplate>
            <DataTemplate>
                <Border>
                    <Button Command="{Binding ElementName=ListView1, Path=DataContext.GetOddsCommand}" CommandParameter="{Binding}">
                         <TextBlock Text="{Binding}" />
                    </Button>
                </Border>
            </DataTemplate>
        </ListView.ItemTemplate>
</ListView>

Notice the DataContext used is that of the ListView not of the ListViewItem...
You might want to do the same kind of binding for the CommandParameter - Depends on what you're really after.

Now, adding the hyperlink inside will cause problems - if you click on the Hyperlink the button isn't really clicked so you won't get the command, if you click on an area without the hyperlink everything will be fine...

If you really do want the hyperlink there... You can set the IsHitTestVisible of the surrounding textblock to false.

e.g.:

<TextBlock IsHitTestVisible="false">
    <Hyperlink NavigateUri="http://www.onet.pl"  >
    <TextBlock Text="{Binding}" />
</TextBlock>

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