DataTemplate button command from binding

Question

I'm using Wpf and I'm passing a List<Value> to a <ItemsControl> in the xaml. I would like to bind the string in the Value Object to the Command of a Button. This xaml part looks like this:

    <Grid Margin="0,0,2,0">
    <Grid Margin="10">
        <ItemsControl Name="details">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Grid Margin="0,0,0,5">
                        <Grid.ColumnDefinitions>
                            ....
                        </Grid.ColumnDefinitions>
                        ...
                        <Button Grid.Column="2"
                                Content="{Binding ButtonContent}"
                                Visibility="{Binding ButtonVisibility}"
                                Command="{Binding ButtonClickMethod}" />
        ...

My Value Class looks like this:

public class Value
{        
    ...
    public string ButtonClickMethod { get; set; }

}

I'm setting the string link this:

v.ButtonClickMethod = "RelatedActivityId_OnClick";

And the Method is in the same class and looks like this:

private void RelatedActivityId_OnClick(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("RelatedActivityId_OnClick");
    }

Everything besides this is working properly and unses the same Object for the binding. What am I doing wrong?

So the string `ButtonClickMethod` contains the name of the method to execute? — H.B., Jul 19 '16 at 14:39

score 1 · Accepted Answer · edited May 23 '17 at 12:22

The Command property of the Button is of type ICommand so you cannot bind it to a string value.

You need to update your ButtonClickMethod to be of type ICommand or create a new property to bind you Command to.

See this answer for a sample implementation of ICommand.

If you need the button to execute code based on a parameter (string value?) then you can use the CommandParameter property, then use that paramters in your Command handler.

public class Value
{        
    public Value()
    {
        ButtonCommand  = new RelayCommand((a) => true, CommandMethod); 
    }

    public RelayCommand ButtonCommand {get; set; }
    public string ButtonClickMethod { get; set; }

    private void CommandMethod(object obj)
    {
        MessageBox.Show(obj?.ToString());
    }
}

and the XAML:

<Button Grid.Column="2"
         Content="{Binding ButtonContent}"
         Visibility="{Binding ButtonVisibility}"
         Command="{Binding ButtonCommand}"
         CommandParameter="{Binding ButtonClickMethod}" />

(If the goal is the execution based on a dynamically set value then just assigning a different command is way easier than using strings and reflection anyway.) — H.B., Jul 19 '16 at 14:44
i'm hoping he can use the parameter to decide which method to call rather than find it though reflection... assuming there is a finite amount of methods that he can call into. — AlexDrenea, Jul 19 '16 at 14:57

score 1 · Answer 2 · answered Jul 19 '16 at 14:48

The Button.Command property binds only to objects which implement the ICommand interface. If you want to invoke a method which its name is ButtonClickMethod, you will have to:

Create a class which implements ICommand interface.
Create a object of that class and bind it to your button (bind it to Button.Command).
Pass the Value.ButtonClickMethod as a CommandParameter to your ICommand object.
Use this to invoke any method you would like to.

DataTemplate button command from binding

2 Answers2