添加项目文件。

GroupLine.App/App.xaml.cs

@@ -0,0 +1,25 @@
+using System.Windows;
+
+namespace GroupLine.App
+{
+    /// <summary>
+    /// App.xaml 的交互逻辑
+    /// </summary>
+    public partial class App : Application
+    {
+        private static System.Threading.Mutex mutex;
+        protected override void OnStartup(StartupEventArgs e)
+        {
+            mutex = new System.Threading.Mutex(true, "OnlyRun_CRNS");
+            if (mutex.WaitOne(0, false))
+            {
+                base.OnStartup(e);
+            }
+            else
+            {
+                MessageBox.Show("程序已经在运行！", "提示");
+                this.Shutdown();
+            }
+        }
+    }
+}