Question

I have a Border with Label inside a Window,

<Border x:Name="Border1" BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Left" Height="21" Margin="229,164,0,0" VerticalAlignment="Top" Width="90" Opacity="0.5">
    <Grid>
        <Label Content="test"/>
    </Grid>
</Border>

I have also a Variable:

public bool vis = false;

How could I bind the vis variable with border Visibility property?

Answer 1

If you already have your bool variable in a viewmodel, you have two things to do:

1. make it a property, like:

   public bool vis { get; set; }

And you need a visibility converter for your property then:

It is described here:

http://social.msdn.microsoft.com/Forums/en/wpf/thread/3c0bef93-9daf-462f-b5da-b830cdee23d9

The example assumes that you have a viewmodel and use Binding

Here is some demo code that I made from your snippet:

ViewModel:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;

namespace StackOverflowWpf2
{
    public class BorderViewModel : INotifyPropertyChanged
    {
        private bool borderVisible = false;

        public bool BorderVisible 
        {
            get
            {
                return borderVisible;
            }

            set
            {
                borderVisible = value;
                NotifyPropertyChanged("BorderVisible");
            }
        }

        private void NotifyPropertyChanged(string info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }
}

XAML:

<Window x:Class="StackOverflowWpf2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <BooleanToVisibilityConverter x:Key="BoolToVisConverter" />
    </Window.Resources>
    <Grid>
        <Border x:Name="Border1" BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Left" Height="21" Margin="229,164,0,0" VerticalAlignment="Top" Width="90" Opacity="0.5"
                Visibility="{Binding Path=BorderVisible, Converter={StaticResource BoolToVisConverter} }" >
            <Grid>
                <Label Content="test"/>
            </Grid>
        </Border>
        <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="381,35,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" 
                />
    </Grid>
</Window>

Some Codebehind quick testcode: (actually is MainWindow.xaml.cs)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace StackOverflowWpf2
{
    /// <summary>
    /// Interaktionslogik für MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public BorderViewModel ViewModel { get; set; }

        public MainWindow()
        {
            InitializeComponent();

            ViewModel = new BorderViewModel();

            this.DataContext = ViewModel;

        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            var vis = (this.DataContext as BorderViewModel).BorderVisible;

            (this.DataContext as BorderViewModel).BorderVisible = !vis;

        }
    }
}