But just how much more efficient is StringBuilder? To find out, I coded a simple Windows Application that gives you the choice of using either. The code is below. (If you want to code this program yourself, simply create the form with the components shown in the illustration.
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As you can see, StringBuilder was 11525 percent (that is, 115 times) faster than using String concatenation. That's a difference worth coding for!
Here's the code! The System.Diagnostics namespace was imported for the StopWatch object.
Imports System.Diagnostics
Public Class Form1
Dim AndTimeSpan As Integer
Dim AppendTimeSpan As Integer
Private Sub TimeEm_Click( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles TimeEm.Click
If UseAnd.Checked Then UseAndTest()
If UseAppend.Checked Then UseAppendTest()
CalcImprovement()
End Sub
Private Sub UseAndTest()
Dim myStopwatch As Stopwatch = New Stopwatch
Dim i As Integer
Dim LoopLimit As Integer = CInt(NumberOfIterations.Text)
Dim TestString As String = ""
Dim myTimeSpan As New TimeSpan
myStopwatch.Reset()
myStopwatch.Start()
For i = 1 To LoopLimit
TestString &= "B"
Next
myStopwatch.Stop()
myTimeSpan = myStopwatch.Elapsed
AndTimeSpan = myTimeSpan.Milliseconds
UsingAnd.Text = myTimeSpan.ToString
End Sub
Private Sub UseAppendTest()
Dim myStopwatch As Stopwatch = New Stopwatch
Dim i As Integer
Dim LoopLimit As Integer = _
CInt(NumberOfIterations.Text)
Dim TestAppend As New System.Text.StringBuilder
Dim myTimeSpan As New TimeSpan
myStopwatch.Reset()
myStopwatch.Start()
For i = 1 To LoopLimit
TestAppend.Append("B")
Next
myStopwatch.Stop()
myTimeSpan = myStopwatch.Elapsed
AppendTimeSpan = myTimeSpan.Milliseconds
UsingAppend.Text = myTimeSpan.ToString
End Sub
Private Sub CalcImprovement()
Try
PercentageImprovement.Text = _
CStr((AndTimeSpan / AppendTimeSpan) * 100)
Catch ex As Exception
PercentageImprovement.Text = ""
End Try
End Sub
End Class
