How To Load SINGLE CELL Value as Object - In 2D Object Array - InvalidCastException

Question

Setup: ---- VB.net - Visual Studio 2010 - Excel Version 2010 - Option Strict ON
The following WORKS FINE all day long for loading MULTIPLE range values IE: ("F2:F5") or more into a 2D Object Array... No problem... as in the following..
Dim myRangeTwo As Range = ws.Range("F2:F5")  ' MULTIPLE CELL RANGE     
Dim arr2(,) As Object = CType(myRangeTwo.Value(XlRangeValueDataType.xlRangeValueDefault), Object(,))
The ws.range("F2:F5") values are stuffed into the myRangeTwo range variable as 2D Objects and then those are easily stuffed into the 2D object array...
But this does not work for a SINGLE cell range...
Dim myRangeTwo As Range = ws.Range("F2:F2")    ' SINGLE CELL RANGE F2 ONLY            
Dim arr2(,) As Object = CType(myRangeTwo.Value(XlRangeValueDataType.xlRangeValueDefault), Object(,))
This triggers an Invalid Cast Exception error on trying to load into the arr2(,).. because the ws.range("F2:F2") is stuffed into the myRangeTwo variable as a "string"
not as an object therefore is not possible to stuff it into an Object Array and so correctly causes the Invalid Cast Error...
How do you handle this seemingly ridiculously simple problem ??
thanks... Cj

Answer 1

Hello,
Simply answer, you need to determine if the range is a single cell or multiple cells. So the following is geared for returning a DataTable for a start and end cell addresses that are different, granted there is no check to see if the cells are valid i.e.
end cell is before start cell i.e.
Since B1 and B10 is a valid range we are good but if we pass in F1:F1 or F10:F10 we must make a decision as per the if statement at the start of the function and if I were expecting this to happen I would have another function that returned a single value.
Option Strict On
Option Infer On
Imports Excel = Microsoft.Office.Interop.Excel
Imports Microsoft.Office
Imports System.Runtime.InteropServices
Module ExcelDemoIteratingData_2
Public Sub DemoGettingDates()
Dim dt As DataTable = OpenExcelAndIterate(
IO.Path.Combine(
AppDomain.CurrentDomain.BaseDirectory,
"GetDatesFromB.xlsx"),
"Sheet1",
"B1",
"B10")
Dim SomeDate As Date = #12/1/2013#
Dim Results =
From T In dt
Where Not IsDBNull(T.Item("SomeDate")) AndAlso T.Field(Of Date)("SomeDate") = SomeDate
Select T
).ToList
If Results.Count > 0 Then
For Each row As DataRow In Results
Console.WriteLine("Row [{0}] Value [{1}]",
row.Field(Of Integer)("Identifier"),
row.Field(Of Date)("SomeDate").ToShortDateString)
Next
End If
End Sub
Public Function OpenExcelAndIterate(
ByVal FileName As String,
ByVal SheetName As String,
ByVal StartCell As String,
ByVal EndCell As String) As DataTable
If StartCell = EndCell Then
' Decide logically what to do or
' throw an exception
End If
Dim dt As New DataTable
If IO.File.Exists(FileName) Then
Dim Proceed As Boolean = False
Dim xlApp As Excel.Application = Nothing
Dim xlWorkBooks As Excel.Workbooks = Nothing
Dim xlWorkBook As Excel.Workbook = Nothing
Dim xlWorkSheet As Excel.Worksheet = Nothing
Dim xlWorkSheets As Excel.Sheets = Nothing
Dim xlCells As Excel.Range = Nothing
xlApp = New Excel.Application
xlApp.DisplayAlerts = False
xlWorkBooks = xlApp.Workbooks
xlWorkBook = xlWorkBooks.Open(FileName)
xlApp.Visible = False
xlWorkSheets = xlWorkBook.Sheets
' For/Next finds our sheet
For x As Integer = 1 To xlWorkSheets.Count
xlWorkSheet = CType(xlWorkSheets(x), Excel.Worksheet)
If xlWorkSheet.Name = SheetName Then
Proceed = True
Exit For
End If
Runtime.InteropServices.Marshal.FinalReleaseComObject(xlWorkSheet)
xlWorkSheet = Nothing
Next
If Proceed Then
dt.Columns.AddRange(
New DataColumn() _
New DataColumn With {.ColumnName = "Identifier", .DataType = GetType(Int32), .AutoIncrement = True, .AutoIncrementSeed = 1},
New DataColumn With {.ColumnName = "SomeDate", .DataType = GetType(Date)}
Dim xlUsedRange = xlWorkSheet.Range(StartCell, EndCell)
Try
Dim ExcelArray(,) As Object = CType(xlUsedRange.Value(Excel.XlRangeValueDataType.xlRangeValueDefault), Object(,))
If ExcelArray IsNot Nothing Then
' Get bounds of the array.
Dim bound0 As Integer = ExcelArray.GetUpperBound(0)
Dim bound1 As Integer = ExcelArray.GetUpperBound(1)
For j As Integer = 1 To bound0
If (ExcelArray(j, 1) IsNot Nothing) Then
dt.Rows.Add(New Object() {Nothing, ExcelArray(j, 1)})
Else
dt.Rows.Add(New Object() {Nothing, Nothing})
End If
Next
End If
Finally
ReleaseComObject(xlUsedRange)
End Try
Else
MessageBox.Show(SheetName & " not found.")
End If
xlWorkBook.Close()
xlApp.UserControl = True
xlApp.Quit()
ReleaseComObject(xlCells)
ReleaseComObject(xlWorkSheets)
ReleaseComObject(xlWorkSheet)
ReleaseComObject(xlWorkBook)
ReleaseComObject(xlWorkBooks)
ReleaseComObject(xlApp)
Else
MessageBox.Show("'" & FileName & "' not located. Try one of the write examples first.")
End If
Return dt
End Function
Private Sub ReleaseComObject(ByVal sender As Object)
Try
If sender IsNot Nothing Then
System.Runtime.InteropServices.Marshal.ReleaseComObject(sender)
sender = Nothing
End If
Catch ex As Exception
sender = Nothing
End Try
End Sub
End Module
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