修改UCD连接需要重启错误

app/device/connection.py

@@ -78,8 +78,27 @@ class ConnectionController:
 
     # -- UCD 连接 ------------------------------------------------
 
-    def connect_ucd(self, display: str) -> bool:
+    def _refresh_ucd_selection(self, display: str) -> tuple[list[str], str | None]:
+        """Rescan devices and return (device list, valid selection or None)."""
+        ucd_list = self.list_ucd_devices()
+        if display in ucd_list:
+            return ucd_list, display
+        return ucd_list, (ucd_list[0] if ucd_list else None)
+
+    def _sync_ucd_combo(self, ucd_list: list[str], selected: str) -> None:
+        app = self._app
+        app.ucd_list_combo.config(values=ucd_list)
+        app.ucd_list_var.set(selected)
+        app.update_config()
+
+    def connect_ucd(self, display: str, *, rescan: bool = True) -> bool:
         """打开指定 UCD 设备。成功返回 True。"""
+        if rescan:
+            _, display = self._refresh_ucd_selection(display)
+        if not display:
+            self._log("未检测到 UCD 设备，请确认电源已打开后重试", level="error")
+            return False
+
         if self._device.state.name != "CLOSED":
             try:
                 self._device.close()
@@ -158,7 +177,11 @@ class ConnectionController:
 
         def worker():
             try:
-                ucd_ok = self.connect_ucd(app.ucd_list_var.get())
+                ucd_list, selected = self._refresh_ucd_selection(app.ucd_list_var.get())
+                app._dispatch_ui(self._sync_ucd_combo, ucd_list, selected or "")
+                ucd_ok = False
+                if selected:
+                    ucd_ok = self.connect_ucd(selected, rescan=False)
                 app._dispatch_ui(
                     app.update_connection_indicator,
                     app.ucd_status_indicator, ucd_ok,
@@ -185,7 +208,19 @@ class ConnectionController:
 
         def worker():
             try:
-                ucd_ok = self.connect_ucd(app.ucd_list_var.get())
+                ucd_list, selected = self._refresh_ucd_selection(app.ucd_list_var.get())
+                app._dispatch_ui(self._sync_ucd_combo, ucd_list, selected or "")
+                if not selected:
+                    app._dispatch_ui(
+                        app.update_connection_indicator,
+                        app.ucd_status_indicator,
+                        False,
+                    )
+                    app._dispatch_ui(app.status_var.set, "未检测到 UCD 设备")
+                    app._dispatch_ui(self._enable_widgets)
+                    return
+
+                ucd_ok = self.connect_ucd(selected, rescan=False)
                 app._dispatch_ui(
                     app.update_connection_indicator,
                     app.ucd_status_indicator,