I am writing two solution to acheive this task the second one is most recommended.

First: 

In first example i am using Excel.Application object

You need to import a reference of Microsoft.Office.Interof.excel

Most important thing, dont forget to close Excel Object otherwise it will be retain in the memory and that cause CONTEXTSWITCHDEADLOCK.

It only occurs when there is a delay in the processing or there is a huge excel file to read.

to resolve this problem follow these steps.

1 . Debug

2 . Exception

3. Managed Debugging Assistants

4. Disable ContextSwitchDeadLock.

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Public Sub ExportExcelIntoText(ByVal FullFileName As String)
Dim oXL As New Excel.Application
Dim oWBK As Excel.Workbook
Dim oWS As Excel.Worksheet
Dim TextFilename As String = FullFileNameTextFilename = Left(TextFilename, Len(TextFilename) – 4)TextFilename += “.txt”
‘deleting a existing file
If File.Exists(TextFilename) Then
File.Delete(TextFilename)
End IfDim fs As New FileStream(TextFilename, FileMode.Create, FileAccess.Write)
Dim sWrtier As New StreamWriter(fs)oWBK = oXL.Workbooks.Open(FullFileName)
oWS = oXL.Worksheets(1)
Try
Dim rowIndex As Int16 = 1
Dim colIndex As Int16 =1sWrtier.BaseStream.Seek(0, SeekOrigin.End)

For rowIndex = 1 To 50
colIndex = 1
If Not (CType(oWS.Cells(rowIndex, colIndex), Excel.Range)).Value2 Is Nothing Then
For colIndex = 1 To 15
If (CType(oXL.Cells(rowIndex, colIndex), Excel.Range)).Value2 Is Nothing Then
sWrtier.Write(“” + vbTab)
Else
sWrtier.Write((CType(oXL.Cells(rowIndex, colIndex), Excel.Range)).Value2.ToString() + vbTab)
End If
Next
End If
sWrtier.WriteLine()
Next‘closing the file
Catch ex As Exception
Console.Write(ex.Message)
Finally
oWBK.Close()
oWBK = Nothing
oXL = Nothing
sWrtier.Close()
sWrtier.Dispose()
sWrtier = Nothing
End Try
End Sub
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Second: In a below example i am reading excel file using OleDB and insert first into dataset and later writing into text file.Public Sub ExportExcelIntoText(ByVal FullFileName As String)
Dim TextFilename As String 
TextFilename = Left(TextFilename, Len(TextFilename) – 4) TextFilename += “.txt”
If File.Exists(TextFilename) Then
File.Delete(TextFilename)
End IfDim fs As FileStream
Dim sWrtier As StreamWriter
Dim da As OleDb.OleDbDataAdapter
Dim ds As DataSetds = Nothing
da = Nothing
sWrtier = Nothing
Tryfs = New FileStream(TextFilename, FileMode.Create, FileAccess.Write)
sWrtier = New StreamWriter(fs)
Dim cnn As New OleDb.OleDbConnection(“Provider=Microsoft.Jet.OLEDB.4.0;Data Source=” + FullFileName + “;Extended Properties=”"Excel 8.0;HDR=YES;”"”)
da = New OleDb.OleDbDataAdapter(“Select * from [Sheet1$]“, cnn)
ds = New DataSet(“ExcelFile”)da.Fill(ds)
Dim rowIndex As DataRow
Dim colIndex As DataColumnsWrtier.BaseStream.Seek(0, SeekOrigin.End)
For Each rowIndex In ds.Tables(0).Rows
For Each colIndex In ds.Tables(0).Columns
If rowIndex(colIndex) Is Nothing Then
sWrtier.Write(“” + vbTab)
Elses
Wrtier.Write(rowIndex(colIndex).ToString + vbTab)
End If
Next
sWrtier.WriteLine()
Next
‘closing the file
Catch ex As Exception
Console.Write(ex.Message)
Finally
ds.Dispose()
ds = Nothing
da.Dispose()
da = Nothing
sWrtier.Close()
sWrtier.Dispose()
sWrtier = Nothing
End Try
End Sub
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I would appreciate your comments.

regards,

Rana