Question

VB.net中把datagridview中的数据导出到电子表格，表格导出后出现"未将对象引用设置到对象的实例。

代码如下：
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim MyExcel As New Microsoft.Office.Interop.Excel.Application()
MyExcel.Application.Workbooks.Add()
MyExcel.Visible = True
'获取标题
Dim Cols As Integer
For Cols = 1 To DataGridView1.Columns.Count
MyExcel.Cells(1, Cols) = DataGridView1.Columns(Cols - 1).HeaderText
Next
'往excel表里添加数据()
Dim i As Integer
For i = 0 To DataGridView1.RowCount - 1
Dim j As Integer
For j = 0 To DataGridView1.ColumnCount - 1
If Me.DataGridView1(j, i).Value Is System.DBNull.Value Then
MyExcel.Cells(i + 2, j + 1) = ""
Else
MyExcel.Cells(i + 2, j + 1) = DataGridView1(j + 0, i + 0).Value.ToString
End If
Next j
Next i
End Sub
End Class
表格能够导出但是程序随后就报错，VS2013提示MyExcel.Cells(i + 2, j + 1) = DataGridView1(j + 0, i + 0).Value.ToString这一句有问题，说是“未将对象引用设置到对象的实例”。请高手指点，这个代码是借鉴百度中的，本人小白一枚。

Answer 1

以下是我以前百度找的资料 希望对你有用 你读取DataGridView到DataGrid然后直接调用函数即可

Public Function ExportXLsD(ByVal datagrid As DataGrid) ', ByVal Title As String)
'Dim Mytable As New DataTable
'Mytable = CType(datagrid.DataSource, DataTable)
If mytable Is Nothing Then
MessageBox.Show("没有记录不能导出数据", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
Exit Function
End If
If mytable.Rows.Count > 0 Then
Dim MyFileName As String
Dim FileName As String
With SaveFileDialog1
.AddExtension = True '如果用户忘记添加扩展名，将自动家上
.DefaultExt = "xls" '默认扩展名
.Filter = "Excel文件(*.xls)|*.xls"
.Title = "文件保存到"
If .ShowDialog = DialogResult.OK Then
FileName = .FileName
End If
End With
MyFileName = Microsoft.VisualBasic.Right(FileName, 4)
If MyFileName = "" Then
Exit Function
End If
If MyFileName = ".xls" Or MyFileName = ".XLS" Then
Dim FS As FileStream = New FileStream(FileName, FileMode.Create)
Dim sw As StreamWriter = New StreamWriter(FS, System.Text.Encoding.Default)
sw.WriteLine(vbTab & FileName & vbTab & Date.Now)
Dim i, j As Integer
Dim str As String = ""
For i = 0 To mytable.Columns.Count - 1
str = mytable.Columns(i).Caption
sw.Write(str & vbTab)
Next
sw.Write(vbCrLf)
For j = 0 To mytable.Rows.Count - 1
For i = 0 To mytable.Columns.Count - 1
Dim strColName, strRow As String
strRow = IIf(mytable.Rows(j).Item(i) Is DBNull.Value, "", mytable.Rows(j).Item(i))
sw.Write(strRow & vbTab)
Next
sw.Write(vbLf)
Next
sw.Close()
FS.Close()
MessageBox.Show("数据导出成功！", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
Else
Exit Function
End If
Else
MessageBox.Show("没有记录不能导出数据", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
End Function
Private Sub OK_Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK_Button.Click
Dim saveExcel As SaveFileDialog
saveExcel = New SaveFileDialog
saveExcel.Filter = "Excel文件(.xls)|*.xls"
Dim filename As String
If saveExcel.ShowDialog = Windows.Forms.DialogResult.Cancel Then Exit Sub
filename = saveExcel.FileName
Dim excel As Excel.Application
excel = New Excel.Application
excel.DisplayAlerts = False
excel.Workbooks.Add(True)
excel.Visible = False
Dim i As Integer
For i = 0 To DataGridView1.Columns.Count - 1
excel.Cells(1, i + 1) = DataGridView1.Columns(i).HeaderText
Next
'设置标题
Dim j As Integer
For i = 0 To DataGridView1.Rows.Count - 1 '填充数据
For j = 0 To DataGridView1.Columns.Count - 1
excel.Cells(i + 2, j + 1) = DataGridView1(j, i).Value
Next
Next
excel.Workbooks(1).SaveCopyAs(filename) '保存
Me.Close()
End Sub

追问

这个代码太长，调试很费力，我问的那个代码能够导出数据，就是表格出来后，VS2013 就报错了
谢谢你的回答，我已经知道原来代码的错误在哪里了，给你分吧

Answer 2

可以分享下你是怎么解决的吗，我的和我你的一模一样的错位，导出的代码这些都一样。