Templates: Quick Overview of SaveAsText and LoadFromText (aka let’s get boring again)
Before we dive into the way the Access Objects are persisted in the Access 2007 template files, I thought it would be best if we talked briefly about the Application.SaveAsText and Application.LoadFromText methods and what they generate and read in, respectively.
In case you don’t recognize these two methods, don’t be surprised: they are hidden and undocumented. Before we get all cloak and dagger, it’s worth saying that these methods are not undocumented as in here, but as in here. Now, let’s take a look at the signature for these methods:
Sub Application.SaveAsText(ObjectName As String, _
ObjectType As AcObjectType, _
FileName As String)
Sub Application.LoadFromText (ObjectType As AcObjectType, _
ObjectName As String, _
FileName As String)
For both of these methods, you specify an object type, the name of the object and a name of a file. For SaveAsText, the given object is stored in a text format in the given file, and for LoadFromText, an object is created given a text format in the given file.
If you look at the text format for a simple form with a single button on it, it looks like this:
Version =20
VersionRequired =20
Checksum =-540535037
Begin Form
DividingLines = NotDefault
AllowDesignChanges = NotDefault
DefaultView =0
TabularCharSet =204
PictureAlignment =2
DatasheetGridlinesBehavior =3
GridX =24
GridY =24
Width =8884
DatasheetFontHeight =11
ItemSuffix =2
Right =7755
Bottom =7860
RecSrcDt = Begin
0x5e1d77333303e340
End
GUID = Begin
0x215548c7105bb74f9c5a62a34852d43e
End
NameMap = Begin
0x0acc0e5500000000000000000000000000000000000000000c00000004000000 ,
0x0000000000000000000000000000
End
DatasheetFontName ="Arial"
FilterOnLoad =0
DatasheetBackColor12 =16777215
ShowPageMargins =0
DisplayOnSharePointSite =1
DatasheetAlternateBackColor =16053492
DatasheetGridlinesColor12 =16765357
FitToScreen =1
Begin
Begin CommandButton
FontSize =11
FontWeight =400
ForeColor =-2147483630
FontName ="Calibri"
LeftPadding =30
TopPadding =30
RightPadding =30
BottomPadding =30
GridlineStyleLeft =0
GridlineStyleTop =0
GridlineStyleRight =0
GridlineStyleBottom =0
GridlineWidthLeft =1
GridlineWidthTop =1
GridlineWidthRight =1
GridlineWidthBottom =1
End
Begin Section
Height =7560
Name ="Detail"
GUID = Begin
0x074cc32161de494c80853bffa393c314
End
AutoHeight =1
Begin
Begin CommandButton
OverlapFlags =85
Left =1800
Top =960
Width =900
Height =840
Name ="Command1"
Caption ="Command1"
GUID = Begin
0x3822e4b79de09b4b8acf9150c95debd3
End
LayoutCachedLeft =1800
LayoutCachedTop =960
LayoutCachedWidth =2700
LayoutCachedHeight =1800
End
End
End
End
End
As you can see, this format is pretty straightforward: blocks are defined by the BEGIN … END clauses and each property off of the object takes the format of <PROPERTY NAME> = <VALUE>.
The control, called “CommandButton” is within a BEGIN … END loop at the end of the description of the form, and its own properties are also described under them. Tabs clearly define a hierarchy here.
You will also notice that the binary properties (such as NameMap and GUID) get BEGIN … END blocks with their value codified in hexadecimal numbers. The LoadFromText/SaveAsText format obviously handles all property types for all Access objects: numbers, text, binary, enums…
Finally, Access is smart enough to only write out properties that have values that don’t match their defaults. This way we save a lot of space writing things we already know.
As an interesting tidbit, you will notice that the option to load and save tables is missing. Yes, you cannot save or load tables using this mechanism, and that’s for historical reasons. This mechanism was never meant as a import/export entry point, but as a simple way to create form, macros, report and queries from a pre-canned source, such as a number of the wizards shipped with Access.