Bind command in WPF using MVVM

You can bind the Command property of the button to any property that returns ICommand. Prism implements a nice convenient command called DelegateCommand that is very easy to use (here is a knock-off of it):

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

private void FuncToCall(object context)
{
    //this is called when the button is clicked
}

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;
}



<Button x:Name="myButton" Command="{Binding MyButtonClickCommand}" />

The CodeProject example How to use Commands in WPF has a very similar example with code that you can easily work through. The previous Stack Overflow question has an example using RoutedCommands that are statically bound to: How to bind Close command to a button, and How to bind WPF button to a command in ViewModelBase? has a slightly more advanced example.

Seeing a lot of answers implementing this ICommand interface, I suggest a simpler option, which is to use the built in System.Windows.Input

Here's an example:

Xaml View:

<Window
    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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    x:Class="SomeDialog"
    SizeToContent="WidthAndHeight"
    WindowStartupLocation="CenterOwner" 
    ResizeMode="CanResizeWithGrip">

    <StackPanel>
        <Button Width="Auto" Command="{Binding ClearCommand}" Content="Clear"/>
    </StackPanel>

</Window>

View Code behind:

using System.Windows;

public partial class SomeDialog : Window
{
    public SomeDialog()
    {
        var vm = new ViewModel();
        DataContext = vm;
        CommandBindings.AddRange(vm.Commands);
        InitializeComponent();
    }
 }

View model:

using System.Windows.Input;

public class ViewModel : ViewModelBase
{
    readonly CommandBindingCollection commands = new CommandBindingCollection();

    public static RoutedUICommand ClearCommand { get; set; } = new RoutedUICommand("Clear", "ClearCommand", typeof(ErrorDialog));

    public CommandBindingCollection Commands
    {
        get
        {
            commands.Add(new CommandBinding(ClearCommand, OnClearExecuted);
            return commands;
        }
    }

    void OnClearExecuted(object sender, ExecutedRoutedEventArgs e)
    {
        view.DialogResult = true; //Indicate things
        view.Close(); //Close the window
    }
}

Call like this:

public void OpenSomeDialog()
{
    var dialog = new SomeDialog() {Owner = Application.Current.MainWindow};
    bool? b = dialog.ShowDialog();
    if (b != null && (bool) b)
        //Do things
}

Now go dialog things.