vb.net循环取值出错

vb.net循环取值出错:

VB.NET code

 Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click                Dim i As Integer        Dim s As String=""        Dim t As Integer        For t = 0 To DataGridView1.Rows.Count - 1            For i = 0 To DataGridView1.Columns.GetColumnCount(DataGridViewElementStates.Visible) - 1                s = s + DataGridView1(i, t).Value.ToString '这里为什么出现并未将物件参考设定为物件的执行个体            Next        Next        MsgBox(s)    End Sub

我不要For t = 0 To DataGridView1.Rows.Count - 1这个循环就没有问题,加上这个就会出现以上的问题了

------解决方法--------------------------------------------------------
s = s + DataGridView1.items(t).cells(i).tostring
------解决方法--------------------------------------------------------
Dim i As Integer
  Dim s As String=""
  Dim t As Integer
  For t = 0 To DataGridView1.Rows.Count - 1
  For i = 0 To DataGridView1.Columns.GetColumnCount(DataGridViewElementStates.Visible) - 1
  s = s + datagridview.rows[t].cells[i].formsetvalue.tostring()
  Next
  Next