Unable to Bubble user-defined Sql RAISERROR(...) to c# exception - sql-server-2008

Question

Unable to Bubble user-defined Sql RAISERROR(...) to c# exception.
Evidence or clues: Sql generated errors bubble to c# but Sql user-defined errors do not bubble to c#. Both are logged in the sql server logs.
EXEC sp_addmessage
#msgnum = 50001,
#severity = 16,
#msgtext = N'This is a user defined error message test_2_sp',
#lang = 'us_english';
DECLARE #FirstNum int = 1
DECLARE #SecondNum int = 0
DECLARE #RowCount int
BEGIN TRY
--SELECT #FirstNum / #SecondNum -- This sql error (not user defined) always comes through by itself with out try ... catch
SELECT #FirstNum + #SecondNum as Result
WHERE #FirstNum = 0 --Un-comment me and watch the error come and go???
--SET #RowCount = ##ROWCOUNT
--SELECT #RowCount AS '#RowCount' -- to see ##ROWCOUNT in SSMS
--RAISERROR('OutSide', 16, 1) WITH Log;
IF ##ROWCOUNT = 0
RAISERROR (50001, -1,-1) WITH Log; --https://msdn.microsoft.com/en-us/library/ms178592.aspx
END TRY
BEGIN CATCH
declare #ErrorMessage nvarchar(max), #ErrorSeverity int, #ErrorState int;
select #ErrorMessage = ERROR_MESSAGE() + ' LineNo ' + cast(ERROR_LINE() as nvarchar(5)), #ErrorSeverity = ERROR_SEVERITY(), #ErrorState = ERROR_STATE();
raiserror (#ErrorMessage, #ErrorSeverity, #ErrorState) WITH Log;
END CATCH
EXEC sp_dropmessage 50001, 'all';
END
C#
protected void Page_Load(object sender, EventArgs e)
{
string ConnectionStringName = "SQLUTLtest";
//string con = #"Data...";
SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings[ConnectionStringName].ToString());
using (SqlCommand cmd = new SqlCommand("Test_2_Sp", sqlcon))
{
cmd.CommandType = CommandType.StoredProcedure;
sqlcon.Open();
try
{
SqlDataAdapter adp = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
adp.Fill(dt);
Response.Write("Hello");
}
catch(Exception ex)
{
Response.Write(ex.Message);
}
finally
{
Response.Write("</br>finally");
}
}
}

Answer 1

Sharing the same response as I did on EE (https://www.experts-exchange.com/questions/28979394/Bubble-user-defined-Sql-RAISERROR-to-c-exception.html):
I think the code will be unable to catch SQL standard Exceptions as well. For example, if I add a SELECT 1/0 (critical divide by zero error) after performing the addition, the code will continue to populate the Data Table and not catch the exception.
Can you update your C# code to the following? Basically, rather than just filling up the DataTable, I am trying to get a DataSet first. This would fail if an exception has been generated. (I tried this on a WinForms App, hence the MessageBoxes. Request you to update the code as necessary).
using (SqlCommand mySqlCommand = new SqlCommand("Test_2_Sp", myCustomConnection))
{
mySqlCommand.CommandType = CommandType.StoredProcedure;
mySqlCommand.Parameters.AddWithValue("#firstnum", "1");
mySqlCommand.Parameters.AddWithValue("#secondnum", "0");
myCustomConnection.Open();
try
{
SqlDataAdapter adp = new SqlDataAdapter(mySqlCommand);
DataSet myDataSet = new DataSet();
adp.Fill(myDataSet);
if (myDataSet.Tables.Count > 0)
{
DataTable dt = myDataSet.Tables[0];
}
MessageBox.Show("Hello World!");
}
catch (Exception ex)
{
MessageBox.Show("Ouch!");
}
finally
{
MessageBox.Show("Good Bye!");
}
}