code 获取失败

ProductionSystem/Untils/Tool/StepTool.cs

@@ -16,7 +16,7 @@ namespace ProductionSystem.Untils.Tool
         
         ProductStepService stepService = new ProductStepService();
         private CurveTool _curveTool = new CurveTool();
-        private PointKeyValue M248 = Program.CommandPointKeyValues.FirstOrDefault(m => m.Key == "D670");
+         
         ParaConfigService paraConfigService=new ParaConfigService();
         DataProductService dataProductService = new DataProductService();
         private readonly ProductStepService productStepService = new ProductStepService();
@@ -35,6 +35,7 @@ namespace ProductionSystem.Untils.Tool
         
         private string GetCode()
         {
+            PointKeyValue M248 = Program.CommandPointKeyValues.FirstOrDefault(m => m.Key == "D670");
             var readM248 = OmronHelper.GetPlcVal(M248.DataType, M248.Address);
             string plcTiaoMa = readM248.val.ToString().Replace("\r", "").Replace("\n", "");
             return plcTiaoMa;