CallMethodAction binding to Button fails

Question

There are no errors. I am trying to learn MVVM. The setup is simple. I get no output when clicking on the button. Xaml should be ok since I have produced interactions part in Blend by dragging behavior to the button. Note: My intention to use methods, but not command, since commands cover only click, but not for example DoubleClick.

<Window
x:Class="MVVM_1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:local="clr-namespace:MVVM_1"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Title="MainWindow"
Width="525"
Height="350"
mc:Ignorable="d"
 >
<Window.DataContext>
    <local:ViewModel/>
</Window.DataContext>
<Grid>
    <Button  x:Name="button"
        Width="75"
        Margin="198,168,0,0"
        HorizontalAlignment="Left"
        VerticalAlignment="Top"
        Content="TestMethod">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseLeftButtonDown" SourceName="button">
                <ei:CallMethodAction MethodName="MethodTesting" 
                                     TargetObject="{Binding}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </Button>
</Grid>

using System.Windows;

namespace MVVM_1
{
public class ViewModel 
    {

    public static void MethodTesting()
        {
            MessageBox.Show("Success!");
        }
    }
}

Shouldn't you have a `sender` and `EventArgs` as parameters in your `MethodTesting`? Also I have found [this answer](https://stackoverflow.com/a/21820832/2029607) which should help with your question. — XAMlMAX, Jul 25 '17 at 13:34

score 0 · Answer 1 · answered Jul 25 '17 at 11:14

You need to use a command to bind the control to the click event.

MVVM - Commands, RelayCommands and EventToCommand

Instead of:

public static void MethodTesting()  
{
    MessageBox.Show("Success!");
}

Use this example:

public ICommand ButtonClickCommand 
{
    get { return new DelegateCommand<object>(FuncToCall, FuncToEvaluate);}
}

private void FuncToCall(object context)
{
    //this is called when the button is clicked
    MessageBox.Show("Success!");
}

private bool FuncToEvaluate(object context)
{
    //this is called to evaluate whether FuncToCall can be called
    //for example you can return true or false based on some validation logic
    return true;
}

Also under this How do you create an OnClick command in WPF MVVM with a programmatically created button? - is another great example.

I am trying to avoid commands, and use methods. Methods promise more since for example DoubleClick is not supported by command. I should have stated that in my question. I will update the question now. — LetzerWille, Jul 25 '17 at 11:24

CallMethodAction binding to Button fails

1 Answers1