Expected semicolon inside if statement

I’ve borrowed some code from another question and answer online (accepted as a working solution), but my compiler seems to expect some extra characters and I can’t see why.

Compiler is expecting all of this:

Line: 37 - ) expected
Line: 37 - ; expected
Line: 37 - Invalid expression term ')'
Line: 37 - ; expected

at the line:

if (ex is Avalara.AvaTax.RestClient.AvaTaxError avaTaxError)

in the code block below

using System;
using SAPbobsCOM;
using SAPbouiCOM;
using Avalara.AvaTax.RestClient;
namespace B1UPCODE 
{ 
    public class B1UPCLASS 
    { 
        public void DynamicCode(params object[] parameters) 
        { 
            SAPbobsCOM.Company company = (SAPbobsCOM.Company)parameters[0];
            SAPbouiCOM.Application application = (SAPbouiCOM.Application)parameters[1];
            SAPbouiCOM.Form form = (SAPbouiCOM.Form)parameters[2];
            SBO.UI.B1Form eventForm = (SBO.UI.B1Form)parameters[3];
            UniversalFunctions.Model.CommonEventObject eventData = (UniversalFunctions.Model.CommonEventObject)parameters[4];
            SBO.AddonLogic.AddonData addonData = (SBO.AddonLogic.AddonData)parameters[5];
            var Client =    new AvaTaxClient("Whatever I want to call the client", "1.0", Environment.MachineName, AvaTaxEnvironment.Production)
                            .WithSecurity("MyUsername", "MyPassword");
                 
            // Verify that we can ping successfully
            var pingResult = Client.Ping();
            if ((bool)pingResult.authenticated)
            {
                application.StatusBar.SetText("Ping success", SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Success);

                try
                {
                    // Create a simple transaction for $100 using the fluent transaction builder
                    var transaction = new TransactionBuilder(Client, "DEFAULT", DocumentType.SalesInvoice, "9999")
                    .WithAddress(TransactionAddressType.SingleLocation, "255 S King St", null, null, "Seattle", "WA", "98104", "US")
                    .WithLineItem(100.0m, 1, "P0000000")
                    .Create();
                }
                catch(Exception ex)
                {

                    if (ex is Avalara.AvaTax.RestClient.AvaTaxError avaTaxError)
                    {
                        // Print the error status code (e.g. "BadRequest", "Unauthorized", etc.)
                        application.StatusBar.SetText("AvaTax Error Type: " + avaTaxError.statusCode, SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);
                        // Print the error message returned by AvaTax
                        application.StatusBar.SetText("AvaTax Error Message: " + avaTaxError.error.error.message.ToString(), SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);

                        // Print the error details for each error encountered
                        application.StatusBar.SetText("AvaTax Error Details:", SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);

                        foreach (var detail in avaTaxError.error.error.details)
                        {
                            // Print the description and help link for each error
                            application.StatusBar.SetText(" Description: " + detail.description, SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);
                            application.StatusBar.SetText(" Help Link: " + detail.helpLink, SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);
                        }

                        // Print the full error response received from AvaTax
                        application.StatusBar.SetText("Full Error Response: " + avaTaxError.error.error.ToString(), SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);

                    }
                }
            }
            else
            {
            application.StatusBar.SetText("Ping fail", SAPbouiCOM.BoMessageTime.bmt_Short, SAPbouiCOM.BoStatusBarMessageType.smt_Error);
            }
        } 
    } 
}

I’ve tried taking the avaTaxError assignment out of the if() comparison and creating a variable inside that block instead – that gets me down to a single expected semicolon. But I still can’t understand where it wants me to put it.

        if (ex is Avalara.AvaTax.RestClient.AvaTaxError)
        {
            var (Avalara.AvaTax.RestClient.AvaTaxError) avaTaxError;

>Solution :

Regardless of the language version, the following code should be more idiomatic, and underline that you actually intend to swallow all other exceptions:

try {
  // code here
} catch (Avalara.AvaTax.RestClient.AvaTaxError avaTaxError) {
  // your if body here
}
catch (Exception) {}