/// <summary>
/// Discover the preferred size of the element.
/// </summary>
/// <param name="context">Layout context.</param>
public override Size GetPreferredSize(ViewLayoutContext context)
{
Size preferredSize = Size.Empty;
// We need an owning form to perform calculations
if (_ownerForm != null)
{
// We only have size if custom chrome is being used with composition
if (_ownerForm.ApplyCustomChrome && _ownerForm.ApplyComposition)
{
try
{
// Create structure that will be populated by call to WM_GETTITLEBARINFOEX
PI.TITLEBARINFOEX tbi = new PI.TITLEBARINFOEX();
tbi.cbSize = (uint)Marshal.SizeOf(tbi);
// Ask the window for the title bar information
PI.SendMessage(_ownerForm.Handle, PI.WM_GETTITLEBARINFOEX, IntPtr.Zero, ref tbi);
// Find width of the button rectangle
int closeWidth = tbi.rcCloseButton.right - tbi.rcCloseButton.left;
int helpWidth = tbi.rcHelpButton.right - tbi.rcHelpButton.left;
int minWidth = tbi.rcMinButton.right - tbi.rcMinButton.left;
int maxWidth = tbi.rcMaxButton.right - tbi.rcMaxButton.left;
int clientWidth = _ownerForm.ClientSize.Width;
int clientScreenRight = _ownerForm.RectangleToScreen(_ownerForm.ClientRectangle).Right;
int leftMost = clientScreenRight;
// Find the left most button edge (start with right side of client area)
if ((closeWidth > 0) && (closeWidth < clientWidth))
leftMost = Math.Min(leftMost, tbi.rcCloseButton.left);
if ((helpWidth > 0) && (helpWidth < clientWidth))
leftMost = Math.Min(leftMost, tbi.rcHelpButton.left);
if ((minWidth > 0) && (minWidth < clientWidth))
leftMost = Math.Min(leftMost, tbi.rcMinButton.left);
if ((maxWidth > 0) && (maxWidth < clientWidth))
leftMost = Math.Min(leftMost, tbi.rcMaxButton.left);
// Our width is the distance between the left most button edge and the right
// side of the client area (this space the buttons are taking up). Plus a small
// extra gap between the first button and the caption elements to its left.
_width = (clientScreenRight - leftMost) + SPACING_GAP;
preferredSize.Width = _width;
}
catch(ObjectDisposedException)
{
// Asking for the WM_GETTITLEBARINFOEX can cause exception if the form level
// Icon has already been disposed. This happens in rare circumstances.
}
}
}
return preferredSize;
}
/// <summary>
/// Discover the preferred size of the element.
/// </summary>
/// <param name="context">Layout context.</param>
public override Size GetPreferredSize(ViewLayoutContext context)
{
Size preferredSize = Size.Empty;
// We need an owning form to perform calculations
if (_ownerForm != null)
{
// We only have size if custom chrome is being used with composition
if (_ownerForm.ApplyCustomChrome && _ownerForm.ApplyComposition)
{
try
{
// Create structure that will be populated by call to WM_GETTITLEBARINFOEX
PI.TITLEBARINFOEX tbi = new PI.TITLEBARINFOEX();
tbi.cbSize = (uint)Marshal.SizeOf(tbi);
// Ask the window for the title bar information
PI.SendMessage(_ownerForm.Handle, PI.WM_GETTITLEBARINFOEX, IntPtr.Zero, ref tbi);
// Find width of the button rectangle
int closeWidth = tbi.rcCloseButton.right - tbi.rcCloseButton.left;
int helpWidth = tbi.rcHelpButton.right - tbi.rcHelpButton.left;
int minWidth = tbi.rcMinButton.right - tbi.rcMinButton.left;
int maxWidth = tbi.rcMaxButton.right - tbi.rcMaxButton.left;
int clientWidth = _ownerForm.ClientSize.Width;
int clientScreenRight = _ownerForm.RectangleToScreen(_ownerForm.ClientRectangle).Right;
int leftMost = clientScreenRight;
// Find the left most button edge (start with right side of client area)
if ((closeWidth > 0) && (closeWidth < clientWidth))
{
leftMost = Math.Min(leftMost, tbi.rcCloseButton.left);
}
if ((helpWidth > 0) && (helpWidth < clientWidth))
{
leftMost = Math.Min(leftMost, tbi.rcHelpButton.left);
}
if ((minWidth > 0) && (minWidth < clientWidth))
{
leftMost = Math.Min(leftMost, tbi.rcMinButton.left);
}
if ((maxWidth > 0) && (maxWidth < clientWidth))
{
leftMost = Math.Min(leftMost, tbi.rcMaxButton.left);
}
// Our width is the distance between the left most button edge and the right
// side of the client area (this space the buttons are taking up). Plus a small
// extra gap between the first button and the caption elements to its left.
_width = (clientScreenRight - leftMost) + SPACING_GAP;
preferredSize.Width = _width;
}
catch (ObjectDisposedException)
{
// Asking for the WM_GETTITLEBARINFOEX can cause exception if the form level
// Icon has already been disposed. This happens in rare circumstances.
}
}
}
return(preferredSize);
}
