hi everyone,

i have a sub that opens a form given the form's name as string and
opens it using System.Reflection. How can I set the form's properties
at runtime. Here is my code.

Public Sub OpenForm(ByVal cFormName)
        Dim frm As Object
        Dim frmType As Type

        Try
            frmType =
Type.GetType(System.Reflection.Assembly.GetExecutingAssembly.GetName.Name()
& cFormName)
            frm = Activator.CreateInstance(frmType)

'**********************************
' i would like to set the form's mdichild property, text, etc before i
show it. how can this be done?
'**********************************

            frmType.InvokeMember("Show",
Reflection.BindingFlags.InvokeMethod, Nothing, frm, Nothing)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub


thanks in advance

diego

well just cast the object pointer to the actuall interface and you can do
everything you want

In your eaxample code i do not see what is the advantage to use reflection
i only use reflection when i need a generic object invoke pattern ( late
bound with public interface )  i.o.w. a plugin architecture

regards

Michel Posseth


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Hi Michael,

thanks for your reply.

what i want to do is, read all my menu items from a database and from
that get the corresponding form name to be opened when the menu item is
clicked.

Anyway i have found a way to do it. below is my code. Please tell me of
what the disadvatahes are when using this approach. Thanks in advance.

'*********************************************
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
        LoadMenu()
        Me.Menu = mnuMain
    End Sub

    Public Sub OpenForm(ByVal cFormName, ByVal frmParent)
        Dim frm As Object
        Dim frmType As Type
        Dim oForm As Form

        Dim lIsOpen As Boolean

        Try
            frmType =
Type.GetType(System.Reflection.Assembly.GetExecutingAssembly.GetName.Name()
& "." & cFormName)
            frm = Activator.CreateInstance(frmType)
            oForm = DirectCast(frm, Form)

            If Not IsFormOpen(cFormName) Then
                frmType.InvokeMember("Show",
Reflection.BindingFlags.InvokeMethod, Nothing, oForm, Nothing)
            End If
            oForm.BringToFront()
            oForm.MdiParent = frmParent
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Private Function IsFormOpen(ByVal cFormName As String) As Boolean
        Dim oForm As Form
        Dim lRet As Boolean = False

        Try
            For Each oForm In Me.MdiChildren
                If oForm.Name = cFormName Then
                    If oForm.Visible Then
                        lRet = True
                        Exit For
                    End If
                End If
            Next
        Catch ex As Exception
        Finally
            IsFormOpen = lRet
        End Try
    End Function

    Private Sub LoadMenu()

        Dim oItem As MyMenuItem
        Dim lFirst As Boolean = True

        mnuMain.MenuItems.Clear()
        Try
            cmd = cnn.CreateCommand
            With cmd
                .CommandText = "SELECT * FROM MENUS ORDER BY ID"
                .CommandType = CommandType.Text
            End With
            da.SelectCommand = cmd
            da.Fill(ds, "MENUS")

            For Each oRow As DataRow In ds.Tables(0).Rows
                Select Case oRow("MENUTYPE")
                    Case 1  '   TOP LEVEL MENU
                        If Not lFirst Then
                            mnuMain.MenuItems.Add(oMenuItem)
                        Else
                            lFirst = False
                        End If
                        oMenuItem = New MenuItem(oRow("MENUITEM"))
                    Case 2  '   MENU ITEM
                        If oRow("MENUKIND") = 0 Then    '   EXIT MENU
                '    CloseMe() just calls Me.Close()
                            oItem = New MyMenuItem(oRow("MENUITEM"),
New System.EventHandler(AddressOf CloseMe))
                        Else    '   REGULAR MENU ITEM
                '    I HAVE CREATED A CLASS THAT INHERITS FROM THE MENUITEM CLASS
                '    SO THAT I CAN STORE THE FORM'S NAME IN THE MENUITEM
                '    DoMenu simply calls the OpenForm procedure
                            oItem = New MyMenuItem(oRow("MENUITEM"),
New System.EventHandler(AddressOf DoMenu))
                            oItem.FormName = oRow("FORMNAME")
                        End If
                        oMenuItem.MenuItems.Add(oItem)
                End Select
            Next
            mnuMain.MenuItems.Add(oMenuItem)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

    Private Sub DoMenu(ByVal sender As System.Object, ByVal e As
System.EventArgs)
        Dim oItem As MyMenuItem
        oItem = DirectCast(sender, MyMenuItem)

        OpenForm(oItem.FormName, Me)
    End Sub
'*********************************************


Ayon kay Michel Posseth  [MCP]:
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