Service/ModbusTcpPlcService.cs

@@ -3,6 +3,8 @@ using System;
 using System.Net;
 using System.Net.Sockets;
 using System.Threading.Tasks;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace MembranePoreTester.Communication
 {
@@ -17,15 +19,31 @@ namespace MembranePoreTester.Communication
             _config = config;
         }
 
-        private async Task EnsureConnectedAsync()
+ public async Task EnsureConnectedAsync(int retryCount = 3)
+    {
+        if (_tcpClient != null && _tcpClient.Connected)
+            return;
+
+        for (int i = 0; i < retryCount; i++)
         {
-            if (_tcpClient == null || !_tcpClient.Connected)
+            try
             {
+                _tcpClient?.Close();
                 _tcpClient = new TcpClient();
-                await _tcpClient.ConnectAsync(_config.IpAddress, _config.Port);
+                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(3));
+                // 现在可以直接使用扩展方法
+                await _tcpClient.ConnectAsync(_config.IpAddress, _config.Port).WithCancellation(cts.Token);
                 _master = ModbusIpMaster.CreateIp(_tcpClient);
+                return;
+            }
+            catch (Exception ex) when (i < retryCount - 1)
+            {
+                System.Diagnostics.Debug.WriteLine($"连接失败，{500}ms 后重试... {ex.Message}");
+                await Task.Delay(500);
             }
         }
+        throw new Exception($"无法连接到 PLC ({_config.IpAddress}:{_config.Port})，请检查网络和 PLC 状态。");
+    }
 
         // 读取两个连续的保持寄存器，转换为32位浮点数（假设大端模式）
         public async Task<float> ReadFloatAsync(ushort startAddress)
@@ -85,11 +103,12 @@ namespace MembranePoreTester.Communication
             return result[0];
         }
 
+        public bool IsConnected => _tcpClient != null && _tcpClient.Connected;
 
         public async Task<ushort[]> ReadHoldingRegistersAsync(ushort startAddress, ushort count)
         {
             await EnsureConnectedAsync();
-            await Task.Delay(100);
+           // await Task.Delay(100);
             return await _master.ReadHoldingRegistersAsync(_config.SlaveId, startAddress, count);
         }
 
@@ -176,6 +195,22 @@ namespace MembranePoreTester.Communication
         {
             _master?.Dispose();
             _tcpClient?.Close();
+            _tcpClient?.Dispose();
+        }
+    }
+
+
+    public static class TaskExtensions
+    {
+        public static async Task WithCancellation(this Task task, CancellationToken cancellationToken)
+        {
+            var tcs = new TaskCompletionSource<bool>();
+            using (cancellationToken.Register(s => ((TaskCompletionSource<bool>)s).TrySetResult(true), tcs))
+            {
+                if (task != await Task.WhenAny(task, tcs.Task))
+                    throw new OperationCanceledException(cancellationToken);
+            }
+            await task;
         }
     }
 }