vb.net how to do IF err.number = 2627 Then errMsg = "This student ID has exists! "

Hi, every one.
Nice see you again.

I stuck at the exception handling part of my project. I feel VB.net has a lousy exception handling.
In vb6, i can catch exception , check the err.number and then use my own text to alert user.
For example:
if it is connection failed, then use my own error text like "Hi, brother turn on that blue PC. SQL server is inside."

If it is violation of primary key, then I can use "Dont register a tag with a existing ID. Please use a new ID."

Now in vb.net, they say i should  catch different specific exceptions and put my own error message.

There are two problem i met, first I cannot find what is that specific exception i wanna catch.
For example, I wanna catch the following error
Message      "Error: 2627: Violation of PRIMARY KEY constraint 'PK__TBL_TAG_INFO__505BE5AD'. Cannot insert duplicate key in object 'TBL_TAG_INFO'.
The statement has been terminated."

Who can tell me the specific exception?

Another Problem, i cannot decide which is narrow excpetion?


See my following code.

I put catch sqlexception before generic exception. Good, inside sqlexception , i can use err.num.
However some error like primary key Violation cannot be caught by sqlexception. It is caught by generic exception. i dont know the reason. maybe primary key Violation is not under sqlexception.
Then In generic exception, there is no err.number. What should i do?
I plan to trim the error number from the Ex.Message. But it seems quite funny. Shouldsome better method be there, right?

'*******************************************************
try
                  dim objDatabase as new clsDatabase("connectionStr")                  
                  
                  iNoAffected = objDatabase.ExecSPNoReturn (strProcName, arrParams)
                  if iNoAffected = 1 then
                        RowTrackData(myRow,CType(Me.iTagID,Int32),sTagType, "Success","")                        
                  End If
            catch sqlEx as SqlException       
                        dim errMsg as String

                      if sqlEx.Number = 17
                        
                              ' Server: Msg 17, Level 16, State 1
                              ' SQL Server does not exist or access denied
                              errMsg = "SQL Server does not exist or access denied"
                        elseif sqlEx.Number =  17142
                        
                              ' Server: Msg 17142, Level 16, State 1
                              ' SQL Server has been paused. No new connection will be allowed
                              errMsg = "SQL Server has been paused. No new connection will be allowed"
                  
                        elseif sqlEx.Number =  18456
                        
                              ' Server: Msg 18456, Level 16, State 1
                              ' Login failed for user 'sa'
                              errMsg = " Login to database failed"
                  
                        end if

                  RowTrackData(myRow, _
                                    CType(Me.iTagID,Int32), _
                                    sTagType, _
                                    "<font color='red'>Failed</font>", _
                                    sqlEx.Message)
            catch ex as Exception       
                  dim errNum as Int64
                        
                  errNum = System.Runtime.InteropServices.Marshal.GetHRForException(ex)
                  if errNum= -2146233088 then
                  else if errNum= -2146233088 then
                  End If
                  RowTrackData(myRow, _
                                    CType(Me.iTagID,Int32), _
                                    sTagType, _
                                    "<font color='red'>Failed</font>", _
                                    "This tag has been existing. Cannot register again.")
            finally
                  ' Create a DataView using the DataTable.
                  'myDataView = New DataView(myDataTable)                  
            end try
'********************************************************