Incremental Intellisense Improvements in VS2010

Introduction

Some improvements like LINQ are substantial, and some just make our lives a little easier. Intellisense in VS2010 has an improvement that is incremental and will make the life of a programmer a little easier.

In VS2008 Intellisense listed members alphabetically by matching characters as you type them. In VS2010 Intellisense lists members using a contains-a approach. Let's take a few minutes to explore this incremental improvement to the VS2010 IDE.

Evolution Lived

In a very early version of C++ I realized one could modify the basic IO functions like printf and add a second version of the methods that wrote directly to a second video buffer. The primary implementation of these methods wrote to the primary video and comprised the programs output. By adding a second monitor-a CGA monitor-and adding the equivalent of trace statement and sending them to the CGA video memory you can have your primary output, which in those days was a text-based GUI-display, on your primary monitor and trace statements appear on the CGA monitor. Viola! Two monitors in the days before it was en vogue.

Video buffer memory is still accessible. To see this open a cmd window, run the debug.exe program and send some data right to video memory. (For the demo I am using EGA video memory because I can't recall the CGA video memory addresses.) It is worth noting that odd numbered memory addresses at EGA memory represent the background and foreground RGB colors, and that my typographic errors (shown in Figure 1) show you just how error prone this approach can be (which in turn demonstrates why good debugging tools were and still are so necessary).

Click here for larger image

Click here for larger image

Figure 1: Entering the raw data right into EGA video memory will display ASCII characters and RGB colors directly to video memory.

Thankfully debugging evolved shortly thereafter with Borland's Turbo Pascal Integrated Development Environment (IDE) and continue to evolve today. Now we have built-in Output windows and Intellisense that make debugging what's going on and figuring out what code base we have to work with substantially easier. (To demonstrate Intellisense for VS2010 I will demonstrate how to redirect IO using .NET in the section "The New and Improved Intellisense".)

Intellisense in Visual Studio 2008

Intellisense in Visual Studio works by displaying members alphabetically. When you type an object name followed by the member of an operator (.) and some alpha-numeric characters Visual Studio will display a drop down window, the first member that start with those characters and then the members that follow alphabetically. Visual Studio 2010 improves on this approach.

The New and Improved Intellisense

When you type an object name, followed by the member of operator in Visual Studio 2010, Visual Studio will display all of the members that start with or contain those characters. Instead of a starts-with, alphabetic listing, Visual Studio 2010 displays a list of members that contain those characters anywhere in the member name, as long as those characters are in the same relative order and the case matches.

To demonstrate, the code in Listing 1 shows you how to redirect console IO to a WinForm of your choosing, instead of the IDE's Output window. I will use this code to show you how Intellisense lists members in VS2010. (Listing 2 shows you how to add a TextBox to a form and initialize the MyStreamWriter class with the TextBox, resulting in Console Write and WriteLine method calls buffering data in the Form's TextBox.)

Listing 1: Building your own debug window in VS2010 using console IO redirection.

  Imports System.Windows.Forms
  Imports System.Text
  
  Public Class MyStreamWriter
    Inherits System.IO.TextWriter
  
    Private control As TextBoxBase
    Private Builder As StringBuilder
  
    Public Sub New(ByVal control As TextBox)
      Me.control = control
      AddHandler control.HandleCreated, _
         New EventHandler(AddressOf OnHandleCreated)
    End Sub
  
    Public Overrides Sub Write(ByVal ch As Char)
      Write(ch.ToString())
    End Sub
  
    Public Overrides Sub Write(ByVal s As String)
      If (control.IsHandleCreated) Then
        AppendText(s)
      Else
        BufferText(s)
      End If
    End Sub
  
    Public Overrides Sub WriteLine(ByVal s As String)
      Write(s + Environment.NewLine)
    End Sub
  
    Private Sub BufferText(ByVal s As String)
      If (Builder Is Nothing) Then
        Builder = New StringBuilder()
      End If
      Builder.Append(s)
    End Sub
  
    Private Sub AppendText(ByVal s As String)
      If (Builder Is Nothing = False) Then
        control.AppendText(Builder.ToString())
        Builder = Nothing
      End If
  
      control.AppendText(s)
    End Sub
  
    Private Sub OnHandleCreated(ByVal sender As Object, _
       ByVal e As EventArgs)
      If (Builder Is Nothing = False) Then
        control.AppendText(Builder.ToString())
        Builder = Nothing
      End If
    End Sub
  
    Public Overrides ReadOnly Property Encoding() As System.Text.Encoding
      Get
        Return Encoding.Default
      End Get
    End Property
  End Class

Listing 2: Initialize MyStreamWriter with a TextBox residing on a form to send Console IO to the TextBox instead of a command window or the Output window in Visual Studio/

  Public Class Form2
    Private writer As MyStreamWriter = Nothing
  
    Private Sub Form1_Load(ByVal sender As System.Object, _
       ByVal e As System.EventArgs) Handles MyBase.Load
      writer = New MyStreamWriter(TextBox1)
      Console.SetOut(writer)
    End Sub
  
  End Class

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This article was originally published on December 18, 2009