How do you inherit StringBuilder in vb.net?

Question

I want to add my own member to the StringBuilder class, but when I go to create it IntelliSense doesn't bring it up.

public class myStringBuilder()
    Inherits System.Text.[StringBuilder should be here]
    ....
end class

Is it even possible? thanks

Answer 1

StringBuilder is NotInheritable (aka sealed in C#) so you cannot derive from it. You could try wrapping StringBuilder in your own class or consider using extension methods instead.

Answer 2

No, StringBuilder is a NotInheritable class. You could try wrapping a StringBuilder instance, but can't inherit from it. You can also use extension methods, if you're using .NET 3.5.

Answer 3

This is what I came up with, for those who are curious:

Imports System.Runtime.CompilerServices
Module sbExtension
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, _
                                   ByVal arg0 As Object)
        oStr.AppendFormat("{0}{1}", String.Format(format, arg0), ControlChars.NewLine)
    End Sub
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, ByVal arg0 As Object, _
                                   ByVal arg1 As Object)
        oStr.AppendFormat("{0}{1}", String.Format(format, arg0, arg1), ControlChars.NewLine)
    End Sub
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, _
                                   ByVal arg0 As Object, _
                                   ByVal arg1 As Object, _
                                   ByVal arg2 As Object)
        oStr.AppendFormat("{0}{1}", String.Format(format, arg0, arg1, arg2), ControlChars.NewLine)
    End Sub
    <Extension()> _
   Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                  ByVal format As String, _
                                  ByVal ParamArray args() As Object)
        oStr.AppendFormat("{0}{1}", String.Format(format, args), ControlChars.NewLine)
    End Sub
End Module

Answer 4

StringBuilder is a sealed class... so inheritance is not allowed.

Answer 5

StringBuilder is sealed. You cannot inherit from it.

Answer 6

If you're using an earlier version of .Net, you can write basically the same StringBuilderExtensions class and then explicitly call the static method instead.

With .Net 3.5: myStringBuilder.MyExtensionMethod(etc...);

Pre- .Net 3.5: StringBuilderExtensions.MyExtensionMethod(myStringBuilder, etc...);