After export to Excel, that excel cannot open

Dim dsExcelExport As New System.Data.DataSet
Dim daExcelExport As New System.Data.SqlClient.SqlDataAdapter

Dim Excel As New Excel.Application

Dim strExcelFile As String
Dim strFileName As String
dsExcelExport.Clear()
daExcelExport.SelectCommand = New SqlCommand
daExcelExport.SelectCommand.Connection =
dtsclass.DatabaseConnection.GetDbConnection("ACCOUNT")
daExcelExport.SelectCommand.CommandText = "select * from myInvoice"
daExcelExport.Fill(dsExcelExport)

Try
With Excel
.SheetsInNewWorkbook = 1
.Workbooks.Add()
.Worksheets(1).Select()

.Range("A1").Value = "BRANCHID"
.Range("B1").Value = "BILLCODE"
.Range("C1").Value = "BILLNAME"
.Range("D1").Value = "COCODE"
.Range("E1").Value = "CONAME"
.Range("F1").Value = "INVNO"


Dim dr As DataRow
Dim i As Integer = 2
For Each dr In dsExcelExport.Tables(0).Rows

.Range("A" & i.ToString).Value = dr("BRANCHID")
.Range("B" & i.ToString).Value = dr("BILLINGCODE")
.Range("C" & i.ToString).Value = dr("BILLINGNAME")
.Range("D" & i.ToString).Value = dr("COCODE")
.Range("E" & i.ToString).Value = dr("CONAME")
.Range("F" & i.ToString).Value = dr("INVNO")
i += 1
Next


strExcelFile = _pFilePath
.ActiveWorkbook().SaveAs(strExcelFile)
.ActiveWorkbook.Close()
End With
MessageBox.Show("File exported sucessfully.", "Exporting done",
MessageBoxButtons.OK, MessageBoxIcon.Information)
''NormalExit:
Excel.Quit()
Excel = Nothing

I think I can export the file sucesfully, However, I cannot open the excel
in the first Time, it is hang . I need to kill the process in Task Manager
and then open the excel again.
Does my procedure got anything wrong ??
thanks a lot


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