Add a InteractiveDialog demo for the DialogExtension.

HandyControlDemo/ViewModel/Controls/DialogDemoViewModel.cs

@@ -1,16 +1,43 @@
 using System;
+using System.Windows.Input;
 using GalaSoft.MvvmLight;
 using GalaSoft.MvvmLight.CommandWpf;
 using HandyControl.Controls;
+using HandyControl.Tools.Extension;
+using HandyControlDemo.Properties.Langs;
 using HandyControlDemo.UserControl;
+using HandyControlDemo.UserControl.Basic;
+using HandyControlDemo.ViewModel.Basic;
 
 namespace HandyControlDemo.ViewModel
 {
     public class DialogDemoViewModel : ViewModelBase
     {
+        private string _dialogResult;
+
         public RelayCommand ShowTextCmd => new Lazy<RelayCommand>(() =>
             new RelayCommand(ShowText)).Value;
 
+        public string DialogResult
+        {
+            get => _dialogResult;
+            set => Set(ref _dialogResult, value);
+        }
+
+        public ICommand ShowInteractiveDialogCmd { get; }
+
+        public DialogDemoViewModel()
+        {
+            DialogResult = Lang.PleaseInput;
+
+            ShowInteractiveDialogCmd = new RelayCommand<string>(async message =>
+            {
+                DialogResult = await Dialog.Show<InteractiveDialog>()
+                    .Initialize<InteractiveDialogViewModel>(vm => vm.Message = message)
+                    .GetResultAsync<string>();
+            });
+        }
+
         private void ShowText()
         {
             Dialog.Show(new TextDialog());