looping read excel data - excel

Question

I need to loop the read data from excel to vb.net and when I reach the last row/column "!##$%^&*()" the excel data will stop read. How can I do that?
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
Dim xlApp As Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
Dim xRange As Excel.Range
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub cmdGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGenerate.Click
'Dim row As String
Dim empty_cell_ctr As Integer = 0 '5
Dim end_of_xlsheet As Boolean = False
Dim sRow As Integer 'start row
Dim col_end As Integer 'col W
'
'loading excel(open and read)
xlApp = New Excel.ApplicationClass
xlWorkBook = xlApp.Workbooks.Open("c:\sample.xls")
xlWorkSheet = xlWorkBook.Worksheets("Timesheet")
xlApp.Visible = True
While Not end_of_xlsheet
If sRow = "'!##$%^&*()_+" Then
xRange = xRange.Cells(sRow, col_end)
end_of_xlsheet = False 'end of sheet
Continue While
End If
sRow += 1
End While
MessageBox.Show(sRow)
End Sub
End Class

Answer 1

You seem to be overthinking this, you can get all of the data in the spreadsheet by accessing the UsedRange property, and then load this into a 2D array variable by accessing the Value2 property of this object like so:
Dim application = New Excel.Application()
Dim workbook As Excel.Workbook = application.Workbooks.Open("C:\aaa\bbb.xlsx")
Dim worksheet As Excel.Worksheet = workbook.Sheets(1)
Dim usedRange = worksheet.UsedRange
Dim usedRangeAs2DArray As Object(,) = usedRange.Value2
workbook.Save()
workbook.Close()
application.Quit()
Marshal.ReleaseComObject(application)

Answer 2

You may use LIKE operator :)
'Not sure why you are trying to check Row number for set of characters...
Excel.Range range = sheet.UsedRange;
Int rows_count = range.Rows.Count;
For (int sRow = 1; sRow <= rows_count; sRow++)
If (sheet.Cells[sRow, col_end].value Like "*'!##$%^&*") Then
'-- input the data to where ever you want. It is best to store it into an array first..
xRange = sheet.Cells[i, col_end].value;
Break;
Else
sRow++;
End If
Please take a look the following reference for better understanding your options.
import data from Excel to VB.Net
read data from Excel to VB.Net