Saving/Loading the Application Docking Layout

The TLMDDockManager component can be used to save/load docking layout. Because the user can undock any number of panels and make them “floating” the saving/loading process has been designed as global process, not the process related to some concrete site.

The SaveToFile and SaveToStream methods can be used to save application docking layout. While saving the TLMDDockManager iterates through all existing in application dock sites (e.g. TLMDDockSite instances), including all floating window sites. It fires the OnSaveSite event before saving each site. The OnSaveSite event can be used as a site filter to prevent saving some particular site.

Saving is performed in XML format. Saved XML basically reflect zone structure, and can look like this:

<?xml version="1.0" encoding="utf-8"?>

<sitelist>

   <site id="frmMain.Site">

      <zone kind="HORZ">

         <zone kind="TABS" autohide="1" activetab="0" size="209">

            <zone kind="PANEL" id="frmMain.pnlCalendar" visible="1" hiddenwidth="209" hiddenheight="517"/>

            <zone kind="PANEL" id="frmMain.pnlTealPanel" visible="1" hiddenwidth="209" hiddenheight="534"/>

         </zone>

         <zone kind="VERT" size="741" dsize="1">

            <zone kind="HORZ" size="309" dsize="0.741007194244604">

               <zone kind="PANEL" id="frmMain.pnlCentral" visible="1" size="521" dsize="0.708843537414966" isspace="1"/>

               <zone kind="TABS" activetab="0" size="214" dsize="0.291156462585034">

                  <zone kind="PANEL" id="frmMain.pnlSiteStructure" visible="1"/>

                  <zone kind="PANEL" id="frmMain.pnlBluePanel" visible="1"/>

                  <zone kind="PANEL" id="frmMain.pnlGreenPanel" visible="1"/>

               </zone>

            </zone>

            <zone kind="TABS" activetab="0" size="108" dsize="0.258992805755396">

               <zone kind="PANEL" id="frmMain.pnlOutput" visible="1"/>

               <zone kind="PANEL" id="frmMain.pnlCallStack" visible="1"/>

               <zone kind="PANEL" id="frmMain.pnlWatches" visible="1"/>

            </zone>

         </zone>

      </zone>

   </site>

</sitelist>

Saving additional application info

OnWriteAppInfo event can be used to write some additional application depended info into XML. This can be, for example, the main application form bounds. The LoadFromFile and LoadFromStream methods can be used to load back previously saved layout. The OnReadAppInfo event handler can be used to read back and apply additional application depended info from the XML:

procedure MainForm.DockManagerWriteAppInfo(Sender: TObject;

  const Xml: ILMDXmlDocument);

var

  elem: ILMDXmlElement;

  i:    Integer;

begin

  elem := Xml.DocumentElement.AppendElement('application');

  elem.SetIntAttr('left', MainForm.Left);

  elem.SetIntAttr('top', MainForm.Top);

  elem.SetIntAttr('width', MainForm.Width);

  elem.SetIntAttr('height', MainForm.Height);

end;

procedure MainForm.DockManagerReadAppInfo(Sender: TObject;

  const Xml: ILMDXmlDocument);

var

  i:    Integer;

  elem: ILMDXmlElement;

  comp: TComponent;

begin

  elem := Xml.DocumentElement.FindElement('application', '', Null);

  if elem <> nil then

  begin

    SetBounds(elem.GetIntAttr('left', MainForm.Left),

              elem.GetIntAttr('top', MainForm.Top),

              elem.GetIntAttr('width', MainForm.Width),

              elem.GetIntAttr('height', MainForm.Height));

  end;

end;

The OnWriteAppInfo event handler shown above will produce the following XML:

<?xml version="1.0" encoding="utf-8"?>

<sitelist>

   ...

   <application left="411" top="264" width="790" height="493"/>

</sitelist>

Deferring startup layouting

Assigning False value to the LoadDesignLayout property of the site at design-time prevents the site to apply the design-time layout at the application start (e.g. while form components loading). So, the empty site will be shown after application start. This can prevent visual flickers while loading previously saved layout.

At the application start the application can check whether the layout has been previously saved (e.g. for example, whether the file exists), and load saved layout directly, skipping applying design-time layout. However, if layout has not been saved, then the design-time layout can be safely applied by calling ApplyDesignLayout method of the TLMDDockManager component. This method also iterates through all existing sites and applies the design-time layout, if required.