Arrays and Visual Studio Tools for Office
When developing solutions using Microsoft Visual Studio Tools for the Microsoft Office System, I (Paul Cornell) find it much easier to pass around intrinsic .NET object instead of Microsoft Office interop objects. Case in point: the Microsoft Office Excel Range object. One issue that always trips me up is that the Excel Range object is one-based, and .NET arrays are generally zero-based. There's nothing in my opinion that makes working with zero-based arrays any better than one-based arrays; it's just that .NET relies very heavily on zero-based arrays, and it's something I always need to be aware of when I'm developing Visual Studio Tools for Office solutions. To demonstrate, last night I wrote a helper function that takes a Range object and places its values into a .NET ArrayList object, as follows:
Private Function CreateArrayListFromRange _
(ByRef Range As Excel.Range) _
As ArrayList
' Purpose: Given an Excel range,
' returns a one-dimensional array of the range's values.
Dim arrayList As New ArrayList
For row As Integer = 1 To Range.Rows.Count
For column As Integer = 1 To Range.Columns.Count
arrayList.Add(CType(Range(row, column), _
Excel.Range).Value2)
Next column
Next row
Return arrayList
End Function
You could call this function from a VSTO event in an Excel solution as follows:
Private Sub ThisWorkbook_Open() Handles ThisWorkbook.Open
' Using one-dimensional array list.
' Assumes you have a worksheet named "Sheet1" and a list
' of values in the A2:C4 range on Sheet1.
Try
Dim arrayList As New ArrayList
arrayList = CreateArrayListFromRange _
(CType(ThisWorkbook.Worksheets("Sheet1"), _
Excel.Worksheet).Range("A2", "C4"))
For item As Integer = 0 To arrayList.Count - 1
MsgBox(arrayList.Item(item) & " (item " & item & ")")
Next item
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Note that in the CreateArrayListFromRange function, I can simply iterate through the values using a one-based nomenclature and write the values to the ArrayList object. However, to read these values out of the ArrayList object in the ThisWorkbook_Open event, I need to use a zero-based nomenclature. If I didn't subtract one from arrayList.Count I would get an out-of-bounds exception.
Another issue with this code snippet is that an ArrayList object works fine if you're only concerned about a single row or single column of cell values. This code doesn't work well for a multidimensional cell array. What I really want is to use the good old Array object and make it mimic the multidimensional nature of a deeper range of cells. Here's how this morning I modified my earlier code to do this:
Private Function CreateArrayFromRange _
(ByRef Range As Excel.Range, _
ByVal rows As Integer, ByVal columns As Integer) As Array
' Purpose: Given an Excel range, returns a multidimensional
' array of the range's values.
Dim array As Array = array.CreateInstance _
(GetType(Object), rows, columns)
For row As Integer = 1 To rows
For column As Integer = 1 To columns
array.SetValue((CType(Range(row, column), _
Excel.Range).Value2), row - 1, column - 1)
Next column
Next row
Return array
End Function
Now I can call this function as follows:
Private Sub ThisWorkbook_Open() Handles ThisWorkbook.Open
' Using multidimensional array list.
' Assumes you have a worksheet named "Sheet1" and a list
' of values in the A2:C4 range on Sheet1.
Try
Dim range As Excel.Range = _
CType(ThisWorkbook.Worksheets("Sheet1"), _
Excel.Worksheet).Range("A2", "C4")
Dim array As Array = _
CreateArrayFromRange(range, range.Rows.Count, _
range.Columns.Count)
For row As Integer = 0 To range.Rows.Count - 1
For column As Integer = 0 To range.Columns.Count - 1
MsgBox(array.GetValue(row, column) & _
" (item " & row & ", " & column & ")")
Next column
Next row
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Notice that I have to be even more careful when I deal with one-based arrays and zero-based arrays, especially when it comes to the array.SetValue call in the CreateArrayFromRange function.
详：http://blogs.msdn.com/vsto/archive/2003/11/25/39744.aspx