Question Object reference not set to an instance of an object.

sai87

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Joined
May 12, 2010
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15
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Beginner
hi all,
i am new to vb.net programming i am trying to export data from dat grid view to the ms excel 2007 worksheet i am getting data into datagridview from an ms access 2007 database my error is :
Object reference not set to an instance of an object.
i have written export to ms excel code in Button1_Click event k
so o am giving my code below pls try to help me out.
VB.NET:
Imports System.Data
Imports System.Data.OleDb
Imports Microsoft.Office.Interop.Excel
Imports Microsoft.Office.Interop
Imports System.Reflection.Missing
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        'Dim ConnString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Documents and Settings\USER\Desktop\D0605\ACCESSLINK1.mdb"
        Dim ConnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Documents and Settings\USER\Desktop\D0605\data1.accdb"
        Dim SQLString As String = "SELECT Company_name, count(Company_name) as counts FROM table1 group by Company_name"
        Dim OleDBConn1 As System.Data.OleDb.OleDbConnection = New System.Data.OleDb.OleDbConnection(ConnString)
        Dim DataSet1 As New DataSet()
        Dim OleDbDataAdapter1 As System.Data.OleDb.OleDbDataAdapter = New System.Data.OleDb.OleDbDataAdapter(SQLString, OleDBConn1)
        OleDBConn1.Open()
        OleDbDataAdapter1.Fill(DataSet1, "table1")
        DataGridView1.DataSource = DataSet1.Tables("table1")
end sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim wapp As New Microsoft.Office.Interop.Excel.Application
        Dim wsheet As New Microsoft.Office.Interop.Excel.Worksheet
        Dim wbook As Microsoft.Office.Interop.Excel.Workbook
        wapp = New Microsoft.Office.Interop.Excel.Application
        wapp.Visible = True
        wsheet = Nothing
        wbook = wapp.Workbooks.Add()
        wsheet = wbook.ActiveSheet
        Dim iX As New Integer
        Dim iY As New Integer
        Dim iC As Integer
        For iC = 0 To DataGridView1.Columns.Count - 1
            wsheet.Cells(1, iC + 1).Value = DataGridView1.Columns(iC).HeaderText
            wsheet.Cells(1, iC + 1).font.bold = True
        Next
        wsheet.Rows(2).select()
        For iX = Nothing To DataGridView1.Rows.Count - 1
            For iY = Nothing To DataGridView1.Columns.Count - 1
                wsheet.Cells(iX + 1, iY + 1) = DataGridView1(iY, iX).Value.ToString
                'wsheet.Cells(iX + 1, iY + 1).v = DataGridView1(iY, iX).Value.ToString
            Next
        Next
        wapp.Visible = True
        wapp.UserControl = True
    End Sub
End Class
 
Last edited by a moderator:

jmcilhinney

VB.NET Forum Moderator
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Please specify which line the exception is thrown on. Also, you can check for yourself which reference on that line is Nothing and then work backwards to where you expect an object to be assigned.
 

sai87

Member
Joined
May 12, 2010
Messages
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Programming Experience
Beginner
The line at which thw error is thrown

Please specify which line the exception is thrown on. Also, you can check for yourself which reference on that line is Nothing and then work backwards to where you expect an object to be assigned.

the line of code where this error is being thrown is :
wsheet.Cells(iX + 1, iY + 1) = DataGridView1(iY, iX).Value.ToString

i tried to solve it but not done so please try to help me out.
 

sai87

Member
Joined
May 12, 2010
Messages
15
Programming Experience
Beginner
reply:Object reference not set to an instance of an object.

So which reference on that line is Nothing? A reference is basically anyhing with a dot after it, i.e. anything you're trying to access a member of.

thanks
actually the problem is
wsheet.Cells(iX + 1, iY + 1).value = DataGridView1(iY, iX).Value.ToString
actually intelligence does nt show the "value" is not an member of worksheet but my assumption is values of datagridview is assigned to excel worksheet cells and the error is Object reference not set to an instance of an object.
so can u tell me where is the problem.
 
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