VB.Net/Development/Reflection

Define Attributes and Use Reflection to get its value

 
Imports System.Reflection

Public Class MainClass
   Public Shared Sub Main()
        Dim MethodObj As System.Reflection.MethodInfo
        Dim MessageDemo As New Demo()
        For Each MethodObj In MessageDemo.GetType.GetMethods()
            Dim Attr As Attribute
            For Each Attr In MethodObj.GetCustomAttributes(False)
                Console.WriteLine(MethodObj.Name)
                Console.WriteLine(Attr)
                Console.WriteLine(CType(Attr, UserName).Name)
            Next
        Next
   
   End Sub
End Class 

Class UserName
    Inherits Attribute
    Public Name As String 
    Public Sub New(ByVal Name As String)
        MyBase.New()
        Me.Name = Name
    End Sub
End Class
Class Demo
    <UserName("Name 1")> Sub DemoMsg()
        Console.WriteLine("Message")
    End Sub
    <UserName("Name 2")> Sub Greet()
        Console.WriteLine("Hello")
    End Sub
End Class

Fill Reflection Data into ListView

 
Imports System
Imports System.Collections
Imports System.Data
Imports System.Reflection
Imports System.Drawing
Imports System.Windows.Forms
Imports System.ruponentModel
Imports System.Drawing.Drawing2D
Imports System.IO
Public Class MainClass
    
    Shared Sub Main()
        Dim form1 As Form = New Form1
        Application.Run(form1)

    End Sub
End Class

Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        " Make column headers.
        lvwProperties.View = View.Details
        lvwProperties.Columns.Clear()
        lvwProperties.Columns.Add("Property", 10, HorizontalAlignment.Left)
        lvwProperties.Columns.Add("Type", 10, HorizontalAlignment.Left)
        lvwProperties.Columns.Add("Value", 10,HorizontalAlignment.Left)
        Dim property_value As Object
        Dim properties_info As PropertyInfo() = GetType(Form1).GetProperties()
        lvwProperties.Items.Clear()
        For i As Integer = 0 To properties_info.Length - 1
            With properties_info(i)
                If .GetIndexParameters().Length = 0 Then
                    property_value = .GetValue(Me, Nothing)
                    If property_value Is Nothing Then
                        ListViewMakeRow(lvwProperties, _
                            .Name, _
                            .PropertyType.ToString, _
                            "<Nothing>")
                    Else
                        ListViewMakeRow(lvwProperties, _
                            .Name, _
                            .PropertyType.ToString, _
                            property_value.ToString)
                    End If
                Else
                    ListViewMakeRow(lvwProperties, _
                        .Name, _
                        .PropertyType.ToString, _
                        "<array>")
                End If
            End With
        Next i
        lvwProperties.Columns(0).Width = -2
        lvwProperties.Columns(1).Width = -2
        lvwProperties.Columns(2).Width = -2
        Dim new_wid As Integer = 30
        For i As Integer = 0 To lvwProperties.Columns.Count - 1
            new_wid += lvwProperties.Columns(i).Width
        Next i
        Me.Size = New Size(new_wid, Me.Size.Height)
    End Sub
    Private Sub ListViewMakeRow(ByVal lvw As ListView, ByVal item_title As String, ByVal ParamArray subitem_titles() As String)
        Dim new_item As ListViewItem = lvw.Items.Add(item_title)
        For i As Integer = subitem_titles.GetLowerBound(0) To _
            subitem_titles.GetUpperBound(0)
            new_item.SubItems.Add(subitem_titles(i))
        Next i
    End Sub
End Class

<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Public Class Form1
    Inherits System.Windows.Forms.Form
    "Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.lvwProperties = New System.Windows.Forms.ListView
        Me.SuspendLayout()
        "
        "lvwProperties
        "
        Me.lvwProperties.Dock = System.Windows.Forms.DockStyle.Fill
        Me.lvwProperties.Location = New System.Drawing.Point(0, 0)
        Me.lvwProperties.Name = "lvwProperties"
        Me.lvwProperties.Size = New System.Drawing.Size(292, 273)
        Me.lvwProperties.TabIndex = 1
        "
        "Form1
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.Add(Me.lvwProperties)
        Me.Name = "Form1"
        Me.Text = "ReflectionListProperties"
        Me.ResumeLayout(False)
    End Sub
    Friend WithEvents lvwProperties As System.Windows.Forms.ListView
End Class

Get Class Member and Property Information from base and inherited Class

 
Imports System.Reflection

Public Class MainClass
   Public Shared Sub Main()
        Dim Book = New Derived()
        Dim Member As MemberInfo
        Console.WriteLine("Members:")
        For Each Member In Book.GetType.GetMembers()
            Console.WriteLine(Member.Name & " " & Member.MemberType)
        Next
        Dim PropertyObj As PropertyInfo
        Console.WriteLine("Properties:")
        For Each PropertyObj In Book.GetType.GetProperties()
            Console.WriteLine(PropertyObj.Name & " " & PropertyObj.PropertyType.ToString())
        Next
        Dim MethodObj As MethodInfo
        Console.WriteLine("Methods:")
        For Each MethodObj In Book.GetType.GetMethods()
            Console.WriteLine(MethodObj.Name & " " & MethodObj.ReturnType.ToString())
        Next
        Dim EventObj As EventInfo
        Console.WriteLine("Events:")
        For Each EventObj In Book.GetType.GetEvents()
            Console.WriteLine(EventObj.Name & " " & EventObj.IsMulticast)
        Next
        Dim InterfaceObj As Type
        Console.WriteLine("Events:")
        For Each InterfaceObj In Book.GetType.GetInterfaces()
            Console.WriteLine(InterfaceObj.Name)
        Next
   
   End Sub
End Class 
    Class Base
        Public ProductID As String
        Public Weight As Double
        Private ProductPrice As Double
        Public Sub New()
        End Sub
        Public ReadOnly Property Price() As Double
            Get
                Return 0
            End Get
        End Property
    End Class
    Class Derived
        Inherits Base
        Implements IFormattable
        Public Title As String
        Public Author As String
        Public Publisher As String
        Public Overridable Overloads Function ToString(ByVal _
          Format As String, ByVal Provider As IFormatProvider) _
          As String Implements IFormattable.ToString
            ToString = Title
        End Function
        Public Sub New()
            MyBase.New()
        End Sub
    End Class

Get Method Information

 
Imports System.Reflection

Public Class MainClass
   Public Shared Sub Main()
        Dim SomeObj = New Demo()
        Dim MethodObj As System.Reflection.MethodInfo
        Console.WriteLine()
        Console.WriteLine("Methods:")
        For Each MethodObj In SomeObj.GetType.GetMethods()
            Console.WriteLine(MethodObj.Name & " " & MethodObj.ReturnType.ToString())
            Dim Param As ParameterInfo
            For Each Param In MethodObj.GetParameters()
                Console.WriteLine(Param.Name & " " & Param.ParameterType.ToString())
            Next
            Console.WriteLine()
        Next
   
   End Sub
End Class 

    Class Demo
        Public Sub A()
        End Sub
        Public Sub B(ByVal Msg As String)
        End Sub
        Public Function C(ByVal A As Integer, ByVal B As Integer) As Integer
        End Function
        Public Sub D(ByVal A As Double, ByVal B As Double, ByVal C As Double)
        End Sub
    End Class

Get Method information and invoke Method using Reflection API

 
Imports System.Reflection

Public Class MainClass
   Public Shared Sub Main()
        Dim SomeObj = New Demo()
        Dim IntegerVar As Integer = 1
        Dim DoubleVar As Double = 100.0
        Dim StringVar As String = "Hello"
        Dim Param As ParameterInfo
        Dim MethodObj As System.Reflection.MethodInfo
        For Each MethodObj In SomeObj.GetType.GetMethods()
            Dim Parameters(MethodObj.GetParameters().Length - 1) As Object
            Dim CallMethod As Boolean = True
            Dim I As Integer = 0
            For Each Param In MethodObj.GetParameters()
                If Equals(Param.ParameterType, IntegerVar.GetType()) Then
                    Parameters(I) = IntegerVar
                ElseIf Equals(Param.ParameterType, DoubleVar.GetType()) Then
                    Parameters(I) = DoubleVar
                ElseIf Equals(Param.ParameterType, StringVar.GetType()) Then
                    Parameters(I) = StringVar
                Else
                    CallMethod = False
                End If
                I = I + 1
            Next
            If (CallMethod) Then
                If MethodObj.GetParameters().Length = 0 Then
                    Console.WriteLine("Calling: " & MethodObj.Name)
                    Console.WriteLine(MethodObj.Invoke(SomeObj, Nothing))
                Else
                    Console.WriteLine("Calling: " & MethodObj.Name)
                    Console.WriteLine(MethodObj.Invoke(SomeObj, Parameters))
                End If
            End If
            Console.WriteLine()
        Next
   
   End Sub
End Class 

    Class Demo
        Public Sub Hello()
        End Sub
        Public Sub ShowMessage(ByVal Msg As String)
        End Sub
        Public Function AddTwoIntegers(ByVal A As Integer, ByVal B As Integer) As Integer
        End Function
        Public Sub ShowThreeDoubles(ByVal A As Double, ByVal B As Double, ByVal C As Double)
        End Sub
    End Class

Reflection: display the member of Form Class

 
Imports System
Imports System.Collections
Imports System.Data
Imports System.IO
Imports System.Xml.Serialization
Imports System.Windows.Forms
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Drawing.Text
Imports System.Drawing.Printing

Public Class MainClass
    Shared Sub Main()
      Dim aForm As New Windows.Forms.Form()
      Dim aType As Type
      aType = aForm.GetType()
      Dim member As Object
      Console.WriteLine("Members of the Form class")
      For Each member In aType.GetMembers
        Console.Write(member.ToString)
      Next
    End Sub
End Class

Reflection Information for Integer Class

 
Imports System
public class MainClass
   Shared Sub Main()
        Dim i As Integer = 15
        Console.WriteLine(i.ToString())
        Console.WriteLine("Hash is: " + i.GetHashCode().ToString())
        Console.WriteLine("Type is: " + i.GetType().ToString)
        Console.WriteLine("Type full name is: " + i.GetType().FullName())
        Console.WriteLine("Type assembly qualified name is: " + i.GetType().AssemblyQualifiedName)
        Console.WriteLine("Namespace is: " + i.GetType().Namespace)
   End Sub
End Class

Reflector Utilities

  
Imports System.Windows.Forms
<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Class Reflector
    Inherits System.Windows.Forms.Form
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.lblAssembly = New System.Windows.Forms.Label
        Me.treeTypes = New System.Windows.Forms.TreeView
        Me.cmdReflect = New System.Windows.Forms.Button
        Me.SuspendLayout()
        "
        "lblAssembly
        "
        Me.lblAssembly.Location = New System.Drawing.Point(10, 9)
        Me.lblAssembly.Name = "lblAssembly"
        Me.lblAssembly.Size = New System.Drawing.Size(272, 12)
        Me.lblAssembly.TabIndex = 5
        "
        "treeTypes
        "
        Me.treeTypes.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.treeTypes.Location = New System.Drawing.Point(10, 29)
        Me.treeTypes.Name = "treeTypes"
        Me.treeTypes.Size = New System.Drawing.Size(362, 276)
        Me.treeTypes.TabIndex = 4
        "
        "cmdReflect
        "
        Me.cmdReflect.Anchor = CType((System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.cmdReflect.Location = New System.Drawing.Point(300, 313)
        Me.cmdReflect.Name = "cmdReflect"
        Me.cmdReflect.Size = New System.Drawing.Size(72, 28)
        Me.cmdReflect.TabIndex = 3
        Me.cmdReflect.Text = "Reflect"
        "
        "Reflector
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(382, 350)
        Me.Controls.Add(Me.lblAssembly)
        Me.Controls.Add(Me.treeTypes)
        Me.Controls.Add(Me.cmdReflect)
        Me.Font = New System.Drawing.Font("Tahoma", 8.25!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Name = "Reflector"
        Me.Text = "Reflector"
        Me.ResumeLayout(False)
    End Sub
    Friend WithEvents lblAssembly As System.Windows.Forms.Label
    Friend WithEvents treeTypes As System.Windows.Forms.TreeView
    Friend WithEvents cmdReflect As System.Windows.Forms.Button
    Private Sub cmdReflect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdReflect.Click
        treeTypes.Nodes.Clear()
        Dim MyAssembly As System.Reflection.Assembly
        MyAssembly = System.Reflection.Assembly.GetExecutingAssembly()
        lblAssembly.Text = MyAssembly.FullName
        Dim MyTypes(), MyType As Type
        Dim MyEvents(), MyEvent As System.Reflection.EventInfo
        Dim MyMethods(), MyMethod As System.Reflection.MethodInfo
        Dim MyProperties(), MyProperty As System.Reflection.PropertyInfo
        MyTypes = MyAssembly.GetTypes()
        For Each MyType In MyTypes
            Dim nodeParent As TreeNode = treeTypes.Nodes.Add(MyType.FullName)
            Dim node As TreeNode = nodeParent.Nodes.Add("Events")
            MyEvents = MyType.GetEvents
            For Each MyEvent In MyEvents
                node.Nodes.Add(MyEvent.Name & " - event handler signature: " & _
                 MyEvent.EventHandlerType.Name)
            Next
            node = nodeParent.Nodes.Add("Methods")
            MyMethods = MyType.GetMethods()
            For Each MyMethod In MyMethods
                node.Nodes.Add(MyMethod.Name)
            Next
            node = nodeParent.Nodes.Add("Properties")
            MyProperties = MyType.GetProperties
            For Each MyProperty In MyProperties
                node.Nodes.Add(MyProperty.Name & "- data type: " & _
                MyProperty.PropertyType.ToString())
            Next
        Next
    End Sub
End Class

Use Reflection to create Class instance and call method

 
Imports System
Imports System.Reflection
 
Public Class MainClass
    Shared Sub Main(  )
         Dim theMathType As Type = Type.GetType("System.Math")
         Dim paramTypes(0) As Type
         paramTypes(0) = Type.GetType("System.Double")
         Dim ConsineInfo As MethodInfo = _
             theMathType.GetMethod("Sin", paramTypes)
         Dim parameters(0) As Object
         parameters(0) = 45 * (Math.PI / 180)
         Dim returnVal As Object
         returnVal = ConsineInfo.Invoke(theMathType, parameters)
         Console.WriteLine("The sine of a 45 degree angle is {0}", _
             returnVal)
    End Sub
  
End Class