添加项目文件。

DotNet.RevitUI/MVVM/RelayCommand.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DotNet.RevitUI.MVVM
+{
+    /// <summary>
+    /// 不带参数通用命令类.
+    /// </summary>
+    /// <seealso cref="System.Windows.Input.ICommand" />
+
+    public class RelayCommand : System.Windows.Input.ICommand
+    {
+        private readonly Action m_Execute;
+
+        private readonly Func<bool> m_CanExecute;
+
+        public event EventHandler CanExecuteChanged
+        {
+            add
+            {
+                if (m_CanExecute != null)
+                    System.Windows.Input.CommandManager.RequerySuggested += value;
+            }
+            remove
+            {
+                if (m_CanExecute != null)
+                    System.Windows.Input.CommandManager.RequerySuggested -= value;
+            }
+        }
+
+        public RelayCommand(Action execute)
+            : this(execute, null)
+        {
+
+        }
+
+        public RelayCommand(Action execute, Func<bool> canExecute)
+        {
+            m_Execute = execute ?? throw new ArgumentNullException("execute");
+
+            m_CanExecute = canExecute;
+        }
+
+        [System.Diagnostics.DebuggerStepThrough]
+        public bool CanExecute(object parameter)
+        {
+            return m_CanExecute == null || m_CanExecute();
+        }
+
+        public void Execute(object parameter)
+        {
+            m_Execute();
+        }
+    }
+}