Interaction.Triggers

  <HTabControl Grid.Row="1" ItemsSource="{Binding Path=OutNursingPartStatementFolderList}" SelectedItem="{Binding Path=SelectedNursingPartFolder}"
               SelectedValuePath="NRST_FLDR_CTG_CD" DisplayMemberPath="FLDR_NM" ItemContainerStyle="{StaticResource treeItemStyle}">
      <i:Interaction.Triggers>
          <i:EventTrigger EventName="SelectionChanged">
              <i:InvokeCommandAction Command="{Binding Path=SelectionFolderChangedCommand}" />
          </i:EventTrigger>
      </i:Interaction.Triggers>
  </HTabControl>




-----------------------------------------------cs
  
        public ICommand SelectionFolderChangedCommand
        {
            get
            {
                if (selectionFolderChangedCommand == null)
                    selectionFolderChangedCommand = new RelayCommand(p => this.selectionFolder());

                return selectionFolderChangedCommand;
            }
        }
  

        private void selectionFolder()
        {
        }

KeyBinding

<HTextBox x:Name="txtSearch" Margin="5,0,0,0" Text="{Binding Path=InputWord, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" PreviewKeyDown="txtSearch_PreviewKeyDown">
  <HTextBox.InputBindings>
      <KeyBinding Key="Enter" Command="{Binding Path=SearchNursingStatementCommand}" CommandParameter="{Binding ElementName=dgrdSearch}" />
  </HTextBox.InputBindings>
</HTextBox>