The Focus method returns true if the control successfully received input focus. The control can have the input focus while not displaying any visual cues of having the focus. This behavior is primarily observed by the nonselectable controls listed below, or any controls derived from them.

A control can be selected and receive input focus if all the following are true: the Selectable value of ControlStyles is set to true, it is contained in another control, and all its parent controls are both visible and enabled.

The Windows Forms controls in the following list are not selectable. Controls derived from these controls are also not selectable.

• Panel

• GroupBox

• PictureBox

• ProgressBar

• Splitter

• Label

• LinkLabel (when there is no link present in the control)

Note:
Focus is a low-level method intended primarily for custom control authors. Instead, application programmers should use the Select method or the ActiveControl property for child controls, or the Activate method for forms.

The following code example sets focus to the specified Control, if it can receive focus.

Public Sub ControlSetFocus(control As Control)
   ' Set focus to the control, if it can receive focus.
   If control.CanFocus Then
      control.Focus()
   End If
End Sub

public void ControlSetFocus(Control control)
{
   // Set focus to the control, if it can receive focus.
   if(control.CanFocus)
   {
      control.Focus();
   }
}

public:
   void ControlSetFocus( Control^ control )
   {

      // Set focus to the control, if it can receive focus.
      if ( control->CanFocus )
      {
         control->Focus();
      }
   }

• UIPermission 

  for all windows to call this method. Associated enumeration: AllWindows value of UIPermissionWindow.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

.NET Framework

.NET Compact Framework

Reference