multibinding.md

 ## MultiBinding
 
+**XAML**
+```csharp
+<Window x:Class="WPF_MultiBinding.MainWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="CodeArsenal.net"
+        Height="158" Width="245"
+        xmlns:local="clr-namespace:WPF_MultiBinding">
+    <Window.Resources>
+        <local:MultiValueConverter x:Key="MultiValueConverter" />
+    </Window.Resources>
+    
+    <Grid>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="10" />
+            <ColumnDefinition Width="65" />
+            <ColumnDefinition Width="Auto" />
+        </Grid.ColumnDefinitions>
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="10" />
+            <RowDefinition Height="Auto" />
+        </Grid.RowDefinitions>
 
+        <TextBox Name="textBoxOne" Grid.Row="0" Height="20" MaxLength="8" Grid.Column="1"
+                 Text="{Binding TextOne, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
+        
+        <TextBox Name="textBoxTwo" Grid.Row="1" Height="20" MaxLength="8" Grid.Column="1" 
+                 Text="{Binding TextTwo, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
+        
+        <TextBox Name="textBoxThree" Grid.Row="2" Height="20" MaxLength="8" Grid.Column="1"
+                 Text="{Binding TextThree, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
+
+        <TextBlock Name="textBlockOutput" Grid.Row="4" Grid.Column="2">
+            <TextBlock.Text>
+                <MultiBinding Converter="{StaticResource MultiValueConverter}">
+                    <Binding Path="TextOne" />
+                    <Binding Path="TextTwo" />
+                    <Binding Path="TextThree" />
+                </MultiBinding>
+            </TextBlock.Text>
+        </TextBlock>
+    </Grid>
+</Window>
+```
+
+**View Model**
+```csharp
+public class ViewModel : INotifyPropertyChanged
+{
+    public ViewModel() { }
+
+    public event PropertyChangedEventHandler PropertyChanged;
+    private string _textOne;
+    public string TextOne 
+    {
+        get { return _textOne; } 
+        set
+        {
+            _textOne = value;
+            NotifyPropertyChanged("TextOne");
+        } 
+    }
+
+    private string _textTwo;
+    public string TextTwo
+    {
+        get { return _textTwo; }
+        set
+        {
+            _textTwo = value;
+            NotifyPropertyChanged("TextTwo");
+        } 
+    }
+
+    private string _textThree;
+    public string TextThree
+    {
+        get { return _textThree; }
+        set
+        {
+            _textThree = value;
+            NotifyPropertyChanged("TextThree");
+        } 
+    }
+
+    public void NotifyPropertyChanged(string propertyName)
+    {
+        if (PropertyChanged != null)
+        {
+            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}
+```
+
+**Conveter**
+```csharp
+public class MultiValueConverter : IMultiValueConverter
+{
+    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+    {
+        string one = values[0] as string;
+        string two = values[1] as string;
+        string three = values[2] as string;
+        if(!string.IsNullOrEmpty(one) && !string.IsNullOrEmpty(two) && !string.IsNullOrEmpty(three))
+        {
+            return one + two + three;
+        }
+        return null;
+    }
+
+    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+    {
+        throw new NotImplementedException();
+    }
+}
+```
+
+- http://www.codearsenal.net/2013/12/wpf-multibinding-example.html