Fix issue （#140 ）

Fix issue （#140 ）

Author: yanjinhuagood

src/WPFDevelopers.Shared/Core/Helpers/ElementHelper.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Windows;
 using System.Windows.Controls;
+using WPFDevelopers.Controls;
 
 namespace WPFDevelopers.Helpers
 {
@@ -82,13 +83,13 @@ private static void OnIsClearChanged(DependencyObject d, DependencyPropertyChang
             if (button != null)
             {
                 if ((bool)e.NewValue)
-                    button.Click += ButtonClear_Click;
+                    button.Click += OnButtonClear_Click;
                 else
-                    button.Click -= ButtonClear_Click;
+                    button.Click -= OnButtonClear_Click;
             }
         }
 
-        private static void ButtonClear_Click(object sender, RoutedEventArgs e)
+        private static void OnButtonClear_Click(object sender, RoutedEventArgs e)
         {
             if (sender is Button button)
             {
@@ -102,6 +103,11 @@ private static void ButtonClear_Click(object sender, RoutedEventArgs e)
                     if (tabControl != null)
                         tabControl.Items.Remove(tabItem); 
                 }
+                else if(button.TemplatedParent is DateRangePicker dateRangePicker)
+                {
+                    dateRangePicker.StartDate = null;
+                    dateRangePicker.EndDate = null;
+                }
             }
         }