ScrollableControl.AutoScrollMargin Property

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets or sets the size of the auto-scroll margin.

public:
 property System::Drawing::Size AutoScrollMargin { System::Drawing::Size get(); void set(System::Drawing::Size value); };

public System.Drawing.Size AutoScrollMargin { get; set; }

member this.AutoScrollMargin : System.Drawing.Size with get, set

Public Property AutoScrollMargin As Size

Property Value

Size

A Size that represents the height and width of the auto-scroll margin in pixels.

Exceptions

ArgumentOutOfRangeException

The Height or Width value assigned is less than 0.

Examples

The following code example uses the derived class, Panel. The example evaluates the location of a text box and changes the appearance and behavior of its parent container, the panel control. The example requires that you have created an instance of a Panel control, TextBox, and Button. Place the text box on the panel so that it overlaps at least one of the panel's edges. Call this function on the click of a button to see the difference in the panel's behavior and appearance.

void SetAutoScrollMargins()
{
   /* If the text box is outside the panel's bounds, 
          turn on auto-scrolling and set the margin. */
   if ( text1->Location.X > panel1->Location.X || text1->Location.Y > panel1->Location.Y )
   {
      panel1->AutoScroll = true;

      /* If the AutoScrollMargin is set to less 
                than (5,5), set it to 5,5. */
      if ( panel1->AutoScrollMargin.Width < 5 || panel1->AutoScrollMargin.Height < 5 )
      {
         panel1->SetAutoScrollMargin( 5, 5 );
      }
   }
}

private void SetAutoScrollMargins()
 {
    /* If the text box is outside the panel's bounds, 
       turn on auto-scrolling and set the margin. */  
    if (text1.Location.X > panel1.Location.X || 
       text1.Location.Y > panel1.Location.Y)
    {
       panel1.AutoScroll = true;
       /* If the AutoScrollMargin is set to less 
          than (5,5), set it to 5,5. */
       if( panel1.AutoScrollMargin.Width < 5 || 
          panel1.AutoScrollMargin.Height < 5)
       {
          panel1.SetAutoScrollMargin(5, 5);
       }
    }
 }

Private Sub SetAutoScrollMargins()
    ' If the text box is outside the panel's bounds,
    ' turn on auto-scrolling and set the margin. 
    If (text1.Location.X > panel1.Location.X) Or _
        (text1.Location.Y > panel1.Location.Y) Then
        panel1.AutoScroll = True
        ' If the AutoScrollMargin is set to less
        ' than (5,5), set it to 5,5. 
        If (panel1.AutoScrollMargin.Width < 5) Or _
            (panel1.AutoScrollMargin.Height < 5) Then
            
            panel1.SetAutoScrollMargin(5, 5)
        End If
    End If
End Sub

Remarks

The auto-scroll margin is the distance between any child controls and the edges of the scrollable parent control. The AutoScrollMargin size is added to the size of any child controls contained in the scrollable control to determine whether or not scroll bars are needed. The AutoScrollMargin property is evaluated when the parent scrollable control is resized or the individual child controls are brought into view, and is used to determine if scroll bars must be displayed. Docked controls are excluded from the calculations that determine if scroll bars must be displayed.

Note

If a docked control's Dock property is set to DockStyle.Fill, the control fills the parent scrollable control and the docked control is ignored when using the AutoScrollMargin to determine whether scroll bars are needed.

If the distance from the edge of a child control to the parent scrollable control is less than the value assigned to the AutoScrollMargin property and the AutoScroll property is set to true, the appropriate scroll bar is displayed.

Note

We recommend, when docking controls within a scrollable control, that you add a child scrollable control, such as a Panel, to contain any other controls that might require scrolling. You should add the child Panel control to the scrollable control and its Dock property set to DockStyle.Fill and its AutoScroll property set to true. You should set the AutoScroll property of the parent scrollable control to false.

Applies to

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