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windows form inherit problem with vb.net vs 2008

• • Reply

  3 months ago

  by bhavusidh

  Bhavesh Patel

  , India

  Joined 7 months ago

  Hi

  In vs 2008 with vb.net I am trying to inherit a form to another form.

  Partial Public Class Form1

  End Class

  Partial Public Class Form2

  Inherits Form1

  End Class

   But it gives following error:

  Error 4 Base class 'Form1' specified for class 'Form2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types. C:\Documents and Settings\rozsoy\My Documents\myvs2008_projects\ONSITEV3\winmobile5_6_vb_csharp_SVS_V3_controls_vs2008\winmob5\Form2.vb 2 14 winmob5
  

   

  Any ideas?

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• • Reply

  3 months ago

  by konikula

  Matej Kasper

  Trutnov, Czech Republic

  Joined 2 years ago

  I have not this problem in 2008. Maybe if you paste bigger part of code?

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• • Reply

  3 months ago

  by bhavusidh

  Bhavesh Patel

  , India

  Joined 7 months ago

  Hi

  In vs 2005 there is inherited form templete but in my vb 2008 I could not find that templete so I just added windows forms.

  Simple 2 forms one inherits the other whic gives error.

  However if I try same thing with c# it works I mean I dont have same problem. But I have to use vb.net.

  I am working with windows mobile 5 and 6 projects but I tried same thing with windows applications as well.

  You are saying you dont have same problem vith vs 2008. Can you send me an example?

  Thanks

  Reside

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• • Reply

  3 months ago

  by bhavusidh

  Bhavesh Patel

  , India

  Joined 7 months ago

  Hi
  I solved that problem if I click show all files on the solution explorer it shows designer.vb file.
  I changed Inherits System.Windows.Forms.Form with Inherits Form1 in Forn2.Designer.vb file.

  The error disappeared but if I open from2 designer it  shows a message :
  visual inheritance is currently disabled because the base class references a device-specific component or contains P/Invoke
  Form1 does not have any thing at the moment.
  How can I that problem. If I put any control on form1 I can not see it on form2. It should happen shuldnt it?
  Thanks
  Reside

  ---

  software developer

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• • Reply

  3 months ago

  by konikula

  Matej Kasper

  Trutnov, Czech Republic

  Joined 2 years ago

  Ok. Now I maybe understand. If you inherited form added by Project/Add, this thing could make you problems. If you simply type both classes in some existing module, and "clone" your own InitialiseComponent and Dispose from some designer.vb, and type inheritance in such class, you shouldn't get no problems. Try this:
  
  Project Add Class;

  Class Select All, Delete;

  Type:
  Class BaseForm
  Inherits Form
  Sub InitializeComponent
  Sub Dispose
  End Class
  
  Class Form2
  Inherits BaseForm
  End Class

  You must only somehow solve overridabilty of Initialize, if you want to use both new classes as forms, not only Inheritance Bases. Possible maybe if you put Overridable Sub Init to Base, which is then called from Base.InitializeComponent. Which is not more overriden than in BaseForm. Also remember MyBase.New before InitializeComponent in Sub New,

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• • Reply

  3 months ago

  by bhavusidh

  Bhavesh Patel

  , India

  Joined 7 months ago

  Thanks for helping me. You are great It is working

  From project I added two classes not windows forms and added as following:

  Public Class BaseForm

  Inherits System.Windows.Forms.Form

  Protected Sub New()

  InitializeComponent()

  End Sub

  Protected Overridable Sub InitializeComponent()

  Me.SuspendLayout()

  '

  'BaseForm

  '

  Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Inherit

  Me.ClientSize = New System.Drawing.Size(240, 294)

  Me.Name = "BaseForm"

  Me.ResumeLayout(False)

  End Sub

  Shadows Sub Dispose()

  End Sub

   

  Protected Overridable Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

  End Sub

  End Class

   

   

  Public Class InheritedForm

  Inherits BaseForm

  Friend WithEvents Button2 As System.Windows.Forms.Button

  Protected Overrides Sub InitializeComponent()

  Me.Button2 = New System.Windows.Forms.Button

  Me.SuspendLayout()

  MyBase.InitializeComponent()

  '

  'Button2

  '

  Me.Button2.Location = New System.Drawing.Point(83, 148)

  Me.Button2.Name = "Button2"

  Me.Button2.Size = New System.Drawing.Size(72, 20)

  Me.Button2.TabIndex = 3

  Me.Button2.Text = "Button2"

  '

  'InheritedForm

  '

  Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Inherit

  Me.ClientSize = New System.Drawing.Size(240, 294)

  Me.Controls.Add(Me.Button2)

  Me.Name = "InheritedForm"

  Me.Controls.SetChildIndex(Me.Button2, 0)

  Me.ResumeLayout(False)

  End Sub

  Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

  End Sub

  End Class

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• • Reply

  3 months ago

  by konikula

  Matej Kasper

  Trutnov, Czech Republic

  Joined 2 years ago

  Take some prsonal excercise in inheriting. Thats just fine (and very easy) way to ease many things :) (anyway I didn't suppose that this helps :] so this is surprise :)

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