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AutoScrollSmallChange Property
See Also  Example
Leadtools.WinForms Namespace > RasterImageViewer Class : AutoScrollSmallChange Property



Gets or sets the amount that the scroll bar is incremented or decremented for a small scroll.

Syntax

Visual Basic (Declaration) 
<BrowsableAttribute(False)>
Public Overridable ReadOnly Property AutoScrollSmallChange As Size
Visual Basic (Usage)Copy Code
Dim instance As RasterImageViewer
Dim value As Size
 
value = instance.AutoScrollSmallChange
C# 
[BrowsableAttribute(false)]
public virtual Size AutoScrollSmallChange {get;}
C++/CLI 
[BrowsableAttribute(false)]
public:
virtual property Size AutoScrollSmallChange {
   Size get();
}

Return Value

The amount that the scroll bar is incremented or decremented.

Example

This example hides the RasterImageViewer control scroll bars and creates two custom scrollbars.

Visual BasicCopy Code
Private Class MyForm3 : Inherits Form
    Public viewer As RasterImageViewer
    Private panel As Panel
    Private myHScroll As HScrollBar
    Private myVScroll As VScrollBar
    Public Sub New(ByVal title As String)
        Text = title

        Me.Size = New Size(750, 450)

        panel = New Panel()
        panel.Dock = DockStyle.Fill
        Controls.Add(panel)

        ' Create the raster viewer
        viewer = New RasterImageViewer()
        viewer.Dock = DockStyle.Fill
        viewer.Width = 500
        viewer.DoubleBuffer = True
        panel.Controls.Add(viewer)

        ' Load an image into the viewer
        RasterCodecs.Startup()
        Dim codecs As RasterCodecs = New RasterCodecs()
        viewer.Image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Sample1.cmp")
        codecs.Dispose()
        RasterCodecs.Shutdown()

        viewer.AutoScroll = False
        Dim size As Size = viewer.AutoScrollMinSize

        ' Create two scrollbar controls for scrolling

        myHScroll = New HScrollBar()
        myHScroll.Location = New Point(100, 50)
        myHScroll.Dock = DockStyle.Top
        myHScroll.Height *= 2
        myHScroll.Minimum = 0
        myHScroll.Maximum = viewer.Image.Width
        AddHandler myHScroll.ValueChanged, AddressOf hScroll_ValueChanged
        panel.Controls.Add(myHScroll)
        myHScroll.BringToFront()

        myVScroll = New VScrollBar()
        myVScroll.Dock = DockStyle.Left
        myVScroll.Location = New Point(100, 100)
        myVScroll.Width *= 2
        myVScroll.Minimum = 0
        myVScroll.Maximum = viewer.Image.Height
        AddHandler myVScroll.ValueChanged, AddressOf vScroll_ValueChanged
        panel.Controls.Add(myVScroll)
        myVScroll.BringToFront()

        viewer.BringToFront()

        OnSizeChanged(EventArgs.Empty)
    End Sub

    Private Sub vScroll_ValueChanged(ByVal sender As Object, ByVal e As EventArgs)
        viewer.ScrollPosition = New Point(myHScroll.Value, myVScroll.Value)
    End Sub

    Private Sub hScroll_ValueChanged(ByVal sender As Object, ByVal e As EventArgs)
        viewer.ScrollPosition = New Point(myHScroll.Value, myVScroll.Value)
    End Sub

    Protected Overrides Sub OnSizeChanged(ByVal e As EventArgs)
        If (Not myHScroll Is Nothing) AndAlso (Not myVScroll Is Nothing) Then
            myHScroll.SmallChange = viewer.AutoScrollSmallChange.Width
            myHScroll.LargeChange = viewer.AutoScrollLargeChange.Width
            myVScroll.SmallChange = viewer.AutoScrollSmallChange.Height
            myVScroll.LargeChange = viewer.AutoScrollLargeChange.Height

            Console.WriteLine("AutoScrollSmallChange {0}", viewer.AutoScrollSmallChange)
            Console.WriteLine("AutoScrollLargeChange {0}", viewer.AutoScrollLargeChange)
            Console.WriteLine("AutoScrollMinSize {0}", viewer.AutoScrollMinSize)
            Console.WriteLine("SmallScrollChangeRatio {0}", viewer.SmallScrollChangeRatio)
            Console.WriteLine("HScroll {0}", viewer.HScroll)
            Console.WriteLine("VScroll {0}", viewer.VScroll)
            Console.WriteLine("")

            myHScroll.Enabled = viewer.HScroll
            myVScroll.Enabled = viewer.VScroll
        End If
        MyBase.OnSizeChanged(e)
    End Sub

End Class

Public Sub RasterImageViewer_HScroll(ByVal title As String)
    Dim form As MyForm3 = New MyForm3(title)
    form.ShowDialog()
End Sub
C#Copy Code
class MyForm3 : Form 
{ 
   public RasterImageViewer viewer; 
   Panel panel; 
   HScrollBar hScroll; 
   VScrollBar vScroll; 
   public MyForm3(string title) 
   { 
      Text = title; 
 
      Size = new Size(750, 450); 
 
      panel = new Panel(); 
      panel.Dock = DockStyle.Fill; 
      Controls.Add(panel); 
 
      // Create the raster viewer 
      viewer = new RasterImageViewer(); 
      viewer.Dock = DockStyle.Fill; 
      viewer.Width = 500; 
      viewer.DoubleBuffer = true; 
      panel.Controls.Add(viewer); 
 
      // Load an image into the viewer 
      RasterCodecs.Startup(); 
      RasterCodecs codecs = new RasterCodecs(); 
      viewer.Image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Sample1.cmp"); 
      codecs.Dispose(); 
      RasterCodecs.Shutdown(); 
 
      viewer.AutoScroll = false; 
      Size size = viewer.AutoScrollMinSize; 
 
      // Create two scrollbar controls for scrolling 
 
      hScroll = new HScrollBar(); 
      hScroll.Location = new Point(100, 50); 
      hScroll.Dock = DockStyle.Top; 
      hScroll.Height *= 2; 
      hScroll.Minimum = 0; 
      hScroll.Maximum = viewer.Image.Width; 
      hScroll.ValueChanged += new EventHandler(hScroll_ValueChanged); 
      panel.Controls.Add(hScroll); 
      hScroll.BringToFront(); 
 
      vScroll = new VScrollBar(); 
      vScroll.Dock = DockStyle.Left; 
      vScroll.Location = new Point(100, 100); 
      vScroll.Width *= 2; 
      vScroll.Minimum = 0; 
      vScroll.Maximum = viewer.Image.Height; 
      vScroll.ValueChanged += new EventHandler(vScroll_ValueChanged); 
      panel.Controls.Add(vScroll); 
      vScroll.BringToFront(); 
 
      viewer.BringToFront(); 
 
      OnSizeChanged(EventArgs.Empty); 
   } 
 
   void vScroll_ValueChanged(object sender, EventArgs e) 
   { 
      viewer.ScrollPosition = new Point(hScroll.Value, vScroll.Value); 
   } 
 
   void hScroll_ValueChanged(object sender, EventArgs e) 
   { 
      viewer.ScrollPosition = new Point(hScroll.Value, vScroll.Value); 
   } 
 
   protected override void OnSizeChanged(EventArgs e) 
   { 
      if((hScroll != null) && (vScroll != null)) 
      { 
         hScroll.SmallChange = viewer.AutoScrollSmallChange.Width; 
         hScroll.LargeChange = viewer.AutoScrollLargeChange.Width; 
         vScroll.SmallChange = viewer.AutoScrollSmallChange.Height; 
         vScroll.LargeChange = viewer.AutoScrollLargeChange.Height; 
 
         Console.WriteLine("AutoScrollSmallChange  {0}", viewer.AutoScrollSmallChange); 
         Console.WriteLine("AutoScrollLargeChange  {0}", viewer.AutoScrollLargeChange); 
         Console.WriteLine("AutoScrollMinSize      {0}", viewer.AutoScrollMinSize); 
         Console.WriteLine("SmallScrollChangeRatio {0}", viewer.SmallScrollChangeRatio); 
         Console.WriteLine("HScroll                {0}", viewer.HScroll); 
         Console.WriteLine("VScroll                {0}", viewer.VScroll); 
         Console.WriteLine(""); 
 
         hScroll.Enabled = viewer.HScroll; 
         vScroll.Enabled = viewer.VScroll; 
      } 
      base.OnSizeChanged(e); 
   } 
 
} 
 
public void RasterImageViewer_HScroll(string title) 
{ 
   MyForm3 form = new MyForm3(title); 
   form.ShowDialog(); 
}

Remarks

A small scroll (or a line scroll) occurs when the user clicks an arrow.

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also