我想使用VBA打开一个visio文件，并更改所有的页边距的形状，然后保存文件，请帮助我！我使用下面的代码，但速度非常慢（文件大小12 Mb（80页）需要30分钟）。请帮助我！

Dim visDoc As Visio.Document
Dim visio_doc
Dim Save_visio_doc
Dim ObjVisio As Object
Dim pag As Visio.Page
Dim pagShape As Visio.shape
Set ObjVisio = CreateObject("Visio.application")
vSet visDoc = ObjVisio.Documents.Open("C\test.vsdx")
For Each pag In visDoc.Pages
    For Each pagShape In pag.Shapes
        pagShape.CellsSRC(visSectionObject, visRowText, visTxtBlkLeftMargin).FormulaU = "2 mm"
        pagShape.CellsSRC(visSectionObject, visRowText, visTxtBlkRightMargin).FormulaU = "2 mm"
        pagShape.CellsSRC(visSectionObject, visRowText, visTxtBlkTopMargin).FormulaU = "2 mm"
        pagShape.CellsSRC(visSectionObject, visRowText, visTxtBlkBottomMargin).FormulaU = "2 mm"
    Next
Next
Visdoc.Save
Visdoc.Close

如果任何人可以帮助，这将是非常感谢。