Ariel Erlijman

Use Operators with Custom Objects – Overloading

Public Shared Operator + (objA as myClass, objB as myClass ) as MyClass
 'code
End Operator

ObjC = ObjA + ObjB

Make Simple Data Types Nullable

dim i as Nullable(Of Integer)
If not i.HasValue then
 Console.WriteLine("i is a null value")
End If

i=100
If i.HasValue then
 Console.WriteLine("Nullable integer i = " & i.Value)
End If

Build Typesafe Generic Classes

Example 1

Public Class GenericList(Of ItemType)
 'Some Code
End Class

Example 2

Public Class GenericList(Of Item Type)
Inherits CollectionBase

Public Function Add(ByVal value as ItemType) as Integer
 Return List.Add(value)
End Function

Public Sub Remove(ByVal value as ItemValue)
 List.Remove(value)
End Sub

Public ReadOnly Property Item(ByVal index as Integer) as ItemType
 Get
  Return CType(List.Item(index),ItemType)
 End Get
End Property

End Class

Program Code

Dim List as New GenericList(Of String)
List.Add("blue")
List.Add("red")

List.Add(Guid.NewGuid()) ' Will be detected by the compiler

Example 3 - More than one type parameter in the class

Public Class GenerichashTable(Of ItemType, KeyType)
 Inherits DictionaryBase
 'Code
End Class
 

Example 4 - Define Constraints to Parameters

Public Class SerializableList(Of ItemType as ISerializable)
 Inherits CollectionBase
 'Code
End Class

Public Class ControlCollection(Of ItemType as Control)
 Inherits CollectionBase
 'Code
End Class

If you want your class to create an instance of the Item

Public Class GenericList(Of ItemType as New)
 Inherits CollectionBase
 'Code
End Class

Example 5 - Define more than one constraint

Public Class GenericList(Of  ItemType as {ISerializable, New})
 Inherits CollectionBase
 'Code
End Class

Generics also works with structures, interfaces, deletates and methods.

Use Strongly Typed Configuration Settings

Double Click the My Project node in the Solution Explorer and select the Settings tab. Add the Name, Type, Scope and Value of your setting.

From your code, type:

dim aSetting as string
aSetting=My.Settings.YourSettingName

Updating User Settings

If you select User from the Scope drop-down list, you can modify that setting in runtime. The modify your setting and save it like this:

MySettings.YourSettingName = “NewValue”
MySettings.Save()

This will create a file under Documents and Settings\[UserName]\Local Settings\Application Data\[Application Name]\[Unique Directory] for the current user only with the selected value.

Use Strongly Typed Resources

1. Double click My Project, Resources, select type images, and add an image. Change the resource name to MyImage
2. Add a picture box or any other control that supports images and type: picturebox1.Image = My.Resources.MyImage

This will embed the image in your assembly. If you want to modify the image, replace the image inside the Resource Directory and recompile. There is no need to modify the code.

This approach is better than the ImageList because ImageList does not support typed resources. However, there are controls that do no support it and you have to fill the imagelist with the resource images in your code if you want to use it in this way.

Use the My Objects to Program Common Tasks

Type My. and select:

My.Computer

Information about the current computer, network, mouse and keyboard, printer, screen and clock. Also sounds, files, registry and clipboard

My.Application

Information about current application and context, assembly version, current folder, culture, command line arguments and log events

My.User

Information about current user

My.Forms

Default instances to any form in the app and to communicate between forms without needing to track from references in another class.

My.WebServices

Provides a default proxy-class instance for every web service

My.Settings

Allows you to retrieve custom settings from your application XML config file

My.Resources

Allows you to retrieve resources-blocks of binary or text data that are compiled intro your application assembly

Create XML Documentation for Your Code

Add ”’ before a sub or function, complete the fields, compile and see the xml file in your bin folder. Use NDoc or any other similar program to consume that xml file and create the xml documentation

Symbolic Rename

Right-click on any local variable and select Rename. This will rename all appropriate instances in your code of that variable.

Symbolic Rename works with any property, class or method.

Right click on a form, and select rename. You will see the same result.