修改EDI PIL增加 签单方式为null判断

Myshipping.Application/EDI/PILEdiHelper.cs

@@ -1807,7 +1807,7 @@ namespace Myshipping.Application.EDI.PIL
                 }
                 tempstr += GetSpaceStr("", 4);//5//Department Code//M//X(4)//19//22//webCSM Department Code (eg SG00) (out from webCSM only)//部门代码//webcsm部门代码（如sg00）（从webcsm只）
                 tempstr += GetSpaceStr("", 3);//6//Booking Agent Code//M//X(3)//23//25//webCSM Booking Agent Code (eg SIN)//订舱代理代码//webcsm订舱代理代码（如犯罪）
-                if (bill.ISSUETYPE.ToString().Trim().ToUpper() == "WAYBILL" || bill.ISSUETYPE.ToString().Trim().ToUpper() == "SEAWAY BILL")
+                if (bill.ISSUETYPE?.Trim().ToUpper() == "WAYBILL" || bill.ISSUETYPE?.Trim().ToUpper() == "SEAWAY BILL")
                 {
                     tempstr += GetSpaceStr("W", 1);//7//BOL Type//M//X(1)//26//26//N-Nominal, G-Negotiable, S-Switch, W-Waybill, M-Memo//公司类型//n-nominal，g-negotiable，S-开关，w-waybill，m-memo
                 }