detect when left mouse button is down while hovering over a button in Visual Basic.net - vb.net

Question

So I'm attempting to create a schedule grid in VB.net (exactly like the scheduler in UTorrent, if anyone is familiar) in a 24x7 layout. I want to be able to click down and drag over a series of squares to change the values of them.
I've been able to find this sample code that mostly works.
Private Sub DataGridView3_MouseHover(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DataGridView3.CellMouseMove
Dim grvScreenLocation As Point = DataGridView3.PointToScreen(DataGridView3.Location)
Dim tempX As Integer = DataGridView.MousePosition.X - grvScreenLocation.X + DataGridView3.Left
Dim tempY As Integer = DataGridView.MousePosition.Y - grvScreenLocation.Y + DataGridView3.Top
Dim hit As DataGridView.HitTestInfo = DataGridView3.HitTest(tempX, tempY)
cellX = hit.RowIndex
cellY = hit.ColumnIndex
TextBox3.Text = cellX
TextBox14.Text = cellY
End Sub
As written, this produces the desired results, however I need to have it only return cellx and celly to the text boxes only when the mouse button is down.

Answer 1

This can be accomplished by handling mouse left button down, mouse move and mouse left button up.
When you receive a mouse left button down event on the grid, record the mouse position and set a flag. In the mouse move handler if the flag is set, highlight all cells between the initial position and the current mouse position. On receiving a mouse left button up (on the grid when the grid is set) commit the cell selection (and clear the flag).
I've used this technique successfully for a fractal zoom.
Here's a rough outline of what you need to do:
Dim isSelecting As Boolean
Dim selectionStart As Point
Protected Overrides Sub OnMouseLeftButtonDown(e As MouseButtonEventArgs)
MyBase.OnMouseLeftButtonDown(e)
Dim position = e.GetPosition(Me)
Dim hit = VisualTreeHelper.HitTest(MyGrid, position)
If hit IsNot Nothing Then
isSelecting = True
selectionStart = position
End If
End Sub
Protected Overrides Sub OnMouseMove(e As MouseEventArgs)
MyBase.OnMouseMove(e)
If isSelecting Then
Dim position = e.GetPosition(Me)
' Update selection
End If
End Sub
Protected Overrides Sub OnMouseLeftButtonUp(e As MouseButtonEventArgs)
MyBase.OnMouseLeftButtonUp(e)
If isSelecting Then
Dim position = e.GetPosition(Me)
' Commit selection
End If
End Sub

Answer 2

This gave me what I wanted.
Private cellX As Integer = 0
Private cellY As Integer = 0
Private Sub DataGridView3_MouseHover(ByVal sender As System.Object, ByVal e As MouseEventArgs) Handles DataGridView3.CellMouseMove
Dim grvScreenLocation As Point = DataGridView3.PointToScreen(DataGridView3.Location)
Dim tempX As Integer = DataGridView.MousePosition.X - grvScreenLocation.X + DataGridView3.Left
Dim tempY As Integer = DataGridView.MousePosition.Y - grvScreenLocation.Y + DataGridView3.Top
Dim hit As DataGridView.HitTestInfo = DataGridView3.HitTest(tempX, tempY)
cellX = hit.RowIndex
cellY = hit.ColumnIndex
If e.Button = Windows.Forms.MouseButtons.Left Then
TextBoxX.Text = cellX
TextBoxY.Text = cellY
DataGridView3.Rows(cellX).Cells(cellY).Style.BackColor = Color.Red
End If
End Sub