Autoincrement a string's last integer value - mysql

Question

I am using vb.net and reading a string from mysql database. Now the string contains "test 1". I want to increment the last digit (1) by the value 1. I somehow used string length and solved it but it works only for string up to "test 10" and then it keeps adding spaces for example: "test 13" and so on. I want to just have strings auto incremented like "test 20" or "test 100". How can I do so?
This is the code I am using:
If reader2.Read Then
var = reader2.GetInt64("version")
a = reader2.GetString("project_id")
location = reader2.GetString("location")
governorate = reader2.GetString("governorate")
memo = reader2.GetString("memo")
title = reader2.GetString("project_title")
var = var + 1
Dim st As String
st = a.Substring(0, a.Length - 2)
st = st & " " & var
b = st
b should have the value of "test 2" or the incremented final value

Answer 1

If in your case projected is “description value” then it is easily done with split function like below:
var = var + 1
Dim st As String
st = a.Split(" ")(0)
st = st & " " & var
b = st

Answer 2

The core issue is that you are using Substring(0, a.Length - 2) where 2 is a constant value which never increases even if the number of digits increases.
If there is a space between the project-name and the number you can use String.Split instead:
Dim version = reader2.GetInt64("version")
Dim projectID = reader2.GetString("project_id")
Dim token As String() = projectID.Split() ' splits by white-space characters '
Dim projectName As String = token(0).Trim()
Dim result As String = String.Format("{0} {1}", projectName, version + 1)
If you want to use Substring instead of Split:
' ... '
Dim projectName = projectID
Dim spaceIndex As Int32 = projectName.IndexOf(" ")
If spaceIndex >= 0 Then projectName = projectName.Substring(0, spaceIndex)
' ... '