String vs. Stringbuilder

Most of the people use string everywhere in their code. Actually when doing string concatenation, do you know what exactly your doing? It has a big drawback mainly in concatenation which can be overcome by StringBuilder. It will give vast improvement in performance when you use concatenation of string over String.

First we will look at what happens when you concatenate two strings

Code:

Dim tString As String = String.Empty

For i As Integer = 1 To 10000
tString += "Test"
Next

Here we're concatenating the string "Test" 10000 times to the string tString. This is a performance leak because we're assigning 9999 new strings!

If we can have something which are be defined only once and add all the strings into it, what can you say about the performance. That's what StringBuilder is doing.

Code:

Dim sb As New System.Text.StringBuilder

For i As Integer = 1 To nCount.Value
sb.Append("Test")
Next

This code will do the same as the code above but faster. If you just want to concatenate a few strings together you can choose your preferred mode, but if you want with 1000's and more you really should work with the stringbuilder. Try the attached example-project to see the difference.