Microsoft VSrollBar behavior or bug with touch screen - windows forms

Question

I found a strange behavior with VScrollBar (vertical scrollbar available in Visual Studio tool box). The problem is \"if I swipe down on the scrollbar, it moves up.

Answer 1

I think what you want is a ViewPort.

Essentially you put a Control inside a PictureBox. The Control has a larger height than the PictureBox making it a ViewPort.

Before

You'll need to change the form designer code to get the control inside the PictureBox:

'
'PictureBox1
'
Me.PictureBox1.Location = New System.Drawing.Point(96, 87)
Me.PictureBox1.Name = "PictureBox1"
Me.PictureBox1.Size = New System.Drawing.Size(231, 195)
Me.PictureBox1.TabIndex = 0
Me.PictureBox1.TabStop = False
'
'VScrollBar1
'
Me.VScrollBar1.Location = New System.Drawing.Point(330, 88)
Me.VScrollBar1.Name = "VScrollBar1"
Me.VScrollBar1.Size = New System.Drawing.Size(34, 194)
Me.VScrollBar1.TabIndex = 2
'
'TextBox1
'
Me.TextBox1.Location = New System.Drawing.Point(0, 0)
Me.TextBox1.Multiline = True
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.Size = New System.Drawing.Size(211, 251)
Me.TextBox1.TabIndex = 3
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(522, 392)
Me.Controls.Add(Me.VScrollBar1)
Me.Controls.Add(Me.PictureBox1)
'======= THIS IS THE CRITICAL CHANGE ======= 
PictureBox1.Controls.Add(Me.TextBox1)

After

Then manually place a ScrollBar to the right of the PictureBox and facilitate the behaviour yourself, eg:

//set the VScroll the difference
VScroll.Max = Textbox.Height - PictureBox.Height;

In the VScroll event:

TextBox.Top = -VScroll.Value;

This will save you from mucking around with system settings in order to produce a QuickViewer custom control.

You can add smarts to it like programming PictureBox drag events to set the ScrollBar (and subsequently the inside controls Top). For most inside controls you'll just need to work out the Height which is easy using a for loop, eg:

foreach(var ctrl in PictureBox.Controls) { 
// tally up the controls height
...

For inside Textbox controls you can work out the Height based on Fontsize and number of lines. There are plenty of examples online showing how to do that. Since you're doing Textbox's with graphics, eg e.Graphics.DrawString it should be easy enough having the inside control as a innerPictureBox.

To swap the scroll/swipe direction set the VScroll default starting Value to its Max value and set the inside controls Top = VScroll.Value (no minus sign needed)