Control Not move in drag and drop - vb.net

Question

In my Application i want to move the control one side another side. That control inside the tablelayoutpanel. I would like to drag the control which is inside the panel and the panel is inside the table layout panel so first i remove the control form panel and add the control in form after that i drag the button control its make the issue not clearly dragging. (that means drag fast its not working properly). My Code is
Private Sub HandleDraggableControlMouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Button2.MouseDown
Dim target As Control = TryCast(sender, Control)
Dim xWidth, xHeight As Integer
If (Not target Is Nothing) Then
xWidth = sender.Width
xHeight = sender.Height
sender.Parent.Controls.Remove(sender)
sender.Dock = DockStyle.None
sender.Width = xWidth
sender.Height = xHeight
Me.Controls.Add(sender)
Dim pt As Point = Me.PointToClient(target.PointToScreen(Point.Empty))
target.Location = pt
target.Parent = Me
target.BringToFront()
Me.isMouseDown = True
Me.cachedControlPos = pt
Me.cachedMousePos = Control.MousePosition
End If
End Sub
Private Sub HandleDraggableControlMouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Button2.MouseMove
If (Me.isMouseDown) Then
Dim target As Control = TryCast(sender, Control)
If (Not target Is Nothing) Then
Dim x As Integer = (Me.cachedControlPos.X + (Control.MousePosition.X - Me.cachedMousePos.X))
Dim y As Integer = (Me.cachedControlPos.Y + (Control.MousePosition.Y - Me.cachedMousePos.Y))
target.Location = New Point(x, y)
'c2 = (c1 + (m2 - m1))
End If
End If
End Sub
Private Sub HandleDraggableControlMouseUp(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Button2.MouseUp
Me.cachedControlPos = Point.Empty
Me.cachedMousePos = Point.Empty
Me.isMouseDown = False
End Sub
My problem is if drag the control fast the control not moved cursor only moved why?. What am doing wrong in my coding?. How is solve the problem?

Answer 1

You need to add the difference between the current mouse position m2 and the cached mouse position m1 to a cached control position c1 to give you the current control position c2.
c2 = (c1 + (m2 - m1))
Something like this:
sender.Location = New Point(
(cachedControlLocation.X + (e.X - startX)),
(cachedControlLocation.Y + (e.Y - startY))
)
Here's a sample form to show you how it works:
Public Class Form1
Public Sub New()
Me.InitializeComponent()
Me.ClientSize = New Size(800, 600)
Me.panel1 = New Panel() With {.Bounds = New Rectangle(10, 10, 300, 300), .BackColor = Color.Red}
Me.panel2 = New Panel() With {.Bounds = New Rectangle(10, 10, 200, 200), .BackColor = Color.Green}
Me.panel3 = New Panel() With {.Bounds = New Rectangle(10, 10, 100, 100), .BackColor = Color.Blue}
Me.panel2.Controls.Add(Me.panel3)
Me.panel1.Controls.Add(Me.panel2)
Me.Controls.Add(Me.panel1)
End Sub
Private Sub HandleDraggableControlMouseDown(sender As Object, e As MouseEventArgs) Handles panel1.MouseDown, panel2.MouseDown, panel3.MouseDown
Dim target As Control = TryCast(sender, Control)
If (Not target Is Nothing) Then
Dim pt As Point = Me.PointToClient(target.PointToScreen(Point.Empty))
target.Parent = Me
target.BringToFront()
target.Location = pt
Me.isMouseDown = True
Me.cachedControlPos = pt
Me.cachedMousePos = Control.MousePosition
End If
End Sub
Private Sub HandleDraggableControlMouseMove(sender As Object, e As MouseEventArgs) Handles panel1.MouseMove, panel2.MouseMove, panel3.MouseMove
If (Me.isMouseDown) Then
Dim target As Control = TryCast(sender, Control)
If (Not target Is Nothing) Then
Dim x As Integer = (Me.cachedControlPos.X + (Control.MousePosition.X - Me.cachedMousePos.X))
Dim y As Integer = (Me.cachedControlPos.Y + (Control.MousePosition.Y - Me.cachedMousePos.Y))
target.Location = New Point(x, y)
'c2 = (c1 + (m2 - m1))
End If
End If
End Sub
Private Sub HandleDraggableControlMouseUp(sender As Object, e As MouseEventArgs) Handles panel1.MouseUp, panel2.MouseUp, panel3.MouseUp
Me.cachedControlPos = Point.Empty
Me.cachedMousePos = Point.Empty
Me.isMouseDown = False
End Sub
Private cachedMousePos As Point
Private cachedControlPos As Point
Private isMouseDown As Boolean
Private WithEvents panel1 As Panel
Private WithEvents panel2 As Panel
Private WithEvents panel3 As Panel
End Class
Update 1
It's important that you set the new location after you've changed the parent and moved it to the front.
target.Parent = Me
target.BringToFront()
target.Location = pt '<---
Update 2
So I've narrowed it down to what's causing this issue, and it turns out to be the Selectable control style. You can verify this by subclassing the button class and remove the style in the constructor.
Public Class UIButton
Inherits Button
Public Sub New()
MyBase.SetStyle(ControlStyles.Selectable, False)
End Sub
End Class
So how can we fix this? Well, AFAIK there's no easy solution. It's to be expected that a selectable control will process the mouse messages in a different way than those who can't. The only way I can think of (and it might be a dirty one) is to subclass the control(s) and intercept the mouse messages. The following code is not a final solution, so use it with caution.
Public Class UIButton
Inherits Button
Protected Overrides Sub WndProc(ByRef m As Message)
Select Case m.Msg
Case WM.LBUTTONDOWN
Dim dw As New DWORD With {.value = m.LParam}
Dim vk As Integer = m.WParam.ToInt32()
MyBase.OnMouseDown(New MouseEventArgs(Windows.Forms.MouseButtons.Left, 0, dw.loword, dw.hiword, 0))
Debug.WriteLine("X={0}, Y={1}", dw.loword, dw.hiword)
Exit Select
Case WM.MOVE
Dim dw As New DWORD With {.value = m.LParam}
Dim vk As Integer = m.WParam.ToInt32()
If (vk = Keys.LButton) Then
MyBase.OnMouseMove(New MouseEventArgs(Windows.Forms.MouseButtons.Left, 0, dw.loword, dw.hiword, 0))
Debug.WriteLine("X={0}, Y={1}", dw.loword, dw.hiword)
End If
Exit Select
Case WM.LBUTTONUP
Dim dw As New DWORD With {.value = m.LParam}
Dim vk As Integer = m.WParam.ToInt32()
MyBase.OnMouseUp(New MouseEventArgs(Windows.Forms.MouseButtons.Left, 0, dw.loword, dw.hiword, 0))
Debug.WriteLine("X={0}, Y={1}", dw.loword, dw.hiword)
Exit Select
End Select
MyBase.WndProc(m)
End Sub
Private Enum WM As Integer
MOVE = &H200
LBUTTONDOWN = &H201
LBUTTONUP = &H202
End Enum
<StructLayout(LayoutKind.Explicit)> _
Private Structure DWORD
<FieldOffset(0)> Public value As Integer
<FieldOffset(0)> Public loword As Short
<FieldOffset(2)> Public hiword As Short
End Structure
End Class