Exporting DataGridView to Excel File

Question

Good day all!
Somebody please help me about this problem that I encounter with exporting from DataGridView to Excel File. I'm still new to VB.Net and all programming stuff so please bear with me if I might sound so stupid and all.. :D
This is the error that I get:
An unhandled exception of type 'System.NullReferenceException' occurred in Program.exe
Additional information: Object reference not set to an instance of an object.
This is the code that I have:
Imports System.Data
Imports System.Data.SqlClient
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Me.Close()
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim xlApp As Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
Dim misValue As Object = System.Reflection.Missing.Value
Dim i As Integer
Dim j As Integer
xlApp = New Excel.ApplicationClass
xlWorkBook = xlApp.Workbooks.Add(misValue)
xlWorkSheet = xlWorkBook.Sheets("sheet1")
For i = 0 To DataGridView1.RowCount - 2
For j = 0 To DataGridView1.ColumnCount - 1
xlWorkSheet.Cells(i + 1, j + 1) = _ ' the error takes place here as per debugger
DataGridView1(j, i).Value.ToString() ' the error takes place here as per debugger
Next
Next
xlWorkSheet.SaveAs("C:\Book1.xls")
xlWorkBook.Close()
xlApp.Quit()
releaseObject(xlApp)
releaseObject(xlWorkBook)
releaseObject(xlWorkSheet)
MsgBox("You can find the file C:\Book1.xls")
End Sub
Private Sub releaseObject(ByVal obj As Object)
Try
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
obj = Nothing
Catch ex As Exception
obj = Nothing
Finally
GC.Collect()
End Try
End Sub
End Class
thanks for all your future help and God bless :)
Geee

Answer 1

thanks for all your help, I just needed to restart my PC and all these codes work. this is my final code:
Module1:
Imports System.Data
Imports System.Data.SqlClient
Imports Excel = Microsoft.Office.Interop.Excel
Module Module1
Public Sub Show1(DataGridView1 As DataGridView)
Dim pProcess() As Process = System.Diagnostics.Process.GetProcessesByName("EXCEL")
For Each p As Process In pProcess
p.Kill()
Next
Dim xlApp As Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
Dim misValue As Object = System.Reflection.Missing.Value
Dim i As Integer
Dim j As Integer
xlApp = New Excel.Application
xlWorkBook = xlApp.Workbooks.Add(misValue)
xlWorkSheet = CType(xlWorkBook.Sheets("sheet1"), Excel.Worksheet)
For i = 0 To DataGridView1.RowCount - 2
For j = 0 To DataGridView1.ColumnCount - 1
If DataGridView1(j, i).Value IsNot Nothing Then
xlWorkSheet.Cells(i + 1, j + 1) = _
DataGridView1(j, i).Value.ToString()
End If
Next
Next
xlWorkSheet.SaveAs(Application.StartupPath & "\" & "GeneratedReport " & Date.Now.ToString("MMdYYYY") & ".xlsx")
xlWorkBook.Close()
xlApp.Quit()
releaseObject(xlApp)
releaseObject(xlWorkBook)
releaseObject(xlWorkSheet)
End Sub
Private Sub releaseObject(ByVal obj As Object)
Try
If obj IsNot Nothing Then
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
obj = Nothing
End If
Catch ex As Exception
obj = Nothing
Finally
GC.Collect()
End Try
End Sub
End Module
Calling it:
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Show1(DataGridView1)
End Sub
But the column header is not included on the excel file, please help me again, thanks :)
Geee