Question

我正在开发一个控制台，我想将按钮拖到网格中：

要拖动按钮，我使用以下过程：

Public drag As Boolean = False
Public ptX As Integer = 0
Public ptY As Integer = 0
Public btn As Button

Private Sub MoveButton_MouseDown(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseDown
    drag = True
    btn = CType(sender, Button)
    ptX = e.X : ptY = e.Y
End Sub

Private Sub MoveButton_MouseMove(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseMove
    If drag Then
        btn.Location = New Point(btn.Location.X + e.X - ptX, btn.Location.Y + e.Y - ptY)
        Me.Refresh()
    End If
End Sub

Private Sub MoveButton_MouseUp(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseUp
    drag = False
End Sub

到目前为止，真好！这适用于此事。但是，我试图突出显示单元格，同时按下它上面的按钮：

为此，我尝试执行以下操作：

Private Sub CellA1_MouseHover(sender As Object, e As EventArgs) Handles CellA1.MouseHover
    If drag Then
        CellA1.BackColor = Color.Red
    End If
End Sub

当然我不能这样做，除非我以某种方式在拖动CellA1.MouseHover时启用MoveButton事件。

任何人都可以帮我吗？

但是，如果您有进一步帮助我的困难意愿，我的最后一个目标是将MoveButton放在红色单元格位置：

但是由于我还没有执行此操作的代码，所以我可以随意使用这部分程序。任何帮助将非常感激。并且，一如既往地提前感谢你们。

Answer 1

由于当您拖动按钮时鼠标实际上不在PictureBox上，因此它永远不会引发任何鼠标事件。您可以执行的操作是调用表单的GetChildAtPoint() method以获取 后面的控件 按钮。一旦你有了，只需验证名称以＆＃34; Cell＆＃34;开头。并改变背面颜色。

要捕捉到单元格的位置，您需要向MouseUp指示我们当前所在的单元格。只需将单元格控件存储在变量中，然后只需设置yourButton.Location = currentCell.Location

即可

以下是我对您的代码所做的更改，为了清晰起见进行了评论：

Public drag As Boolean = False
Public ptX As Integer = 0
Public ptY As Integer = 0
Public btn As Button
Public prevCtrl As Control = Nothing 'Store the previous Cell the button was dragged over.
'                                     We need this to be able to reset the BackColor of the Cell, 
'                                     and also so that you can snap to its location once you drop the button.

Private Sub MoveButton_MouseDown(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseDown
    'No changes made here.
    drag = True
    btn = CType(sender, Button)
    ptX = e.X : ptY = e.Y
End Sub

Private Sub MoveButton_MouseMove(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseMove
    If drag Then
        btn.Location = New Point(btn.Location.X + e.X - ptX, btn.Location.Y + e.Y - ptY)

        'Go 1 pixel up, or else GetChildAtPoint() will return the button instead of the control behind it.
        Dim LookPoint As Point = Point.Subtract(btn.Location, New Size(0, 1))

        'Get the control located below/behind the button.
        Dim ControlBelow As Control = Me.GetChildAtPoint(LookPoint, GetChildAtPointSkip.Invisible Or GetChildAtPointSkip.Disabled) 'Ignore invisible or disabled controls.

        'Check so that the previous cell is not also the current cell. If they're the same then we won't change anything.
        If prevCtrl IsNot ControlBelow Then

            'Ok, the current cell and the previous cell are not the same.
            'Now check if there was any previous cell at all.
            If prevCtrl IsNot Nothing Then
                'There was a previous cell, but since the button 
                'is no longer hovering over it we reset its BackColor.
                prevCtrl.BackColor = Color.White
                prevCtrl = Nothing
            End If

            'Check that there infact is a control behind the button,
            'and also check that its name starts with "Cell".
            If ControlBelow IsNot Nothing AndAlso ControlBelow.Name.StartsWith("Cell", StringComparison.OrdinalIgnoreCase) Then
                'The control behind the button is a valid Cell. Change its BackColor.
                ControlBelow.BackColor = Color.Red
                prevCtrl = ControlBelow 'The previous cell is now the current cell.
            End If

        End If

        'Me.Refresh() - this is a very unnecessary call, it will just eat CPU. The form does not need to be redrawn at this point.
    End If
End Sub

Private Sub MoveButton_MouseUp(sender As Object, e As MouseEventArgs) Handles MoveButton.MouseUp
    'Check if we dragged the button. At this point prevCtrl is the current cell (if it's not Nothing).
    If drag = True AndAlso prevCtrl IsNot Nothing Then
        btn.Location = prevCtrl.Location 'Snap to the cell's location.
        prevCtrl.BackColor = Color.White 'Reset the cell's BackColor.
        prevCtrl = Nothing 'Reset this since we're no longer dragging the button.
    End If

    drag = False
End Sub

它就像一个魅力！

拖动对象时启用其他事件

1 个答案: