主题：获取EXCEL单元格的值一直报错

请问:下述报错如何修改语句代码 ?

Dim App As New MSExcel.Application

Dim Wb As MSExcel.WorkBook = App.WorkBooks.Open(输出文件)

Dim Ws As MSExcel.WorkSheet = Wb.WorkSheets(1)

Dim Rg_Use As MSExcel.Range = Ws.UsedRange

MessageBox.Show(Rg_Use.Rows.Count & "  " & Rg_Use.Columns.Count & "  " & Rg_Use.Count)

For i As Integer = 1 To Rg_Use.Rows.Count

    For j As Integer = 1 To Rg_Use.Columns.Count

        Dim Rg_val As MSExcel.Range = Ws.Cells(i, j)

        'Dim rg_v As String = Rg_val.Value.ToString ' 出错语句

        MessageBox.Show(rg_val.Value.ToString)  ' 这里不出错

        If Rg_val.Value.ToString <> "" AndAlso rg_val.Value.ToString.Contains("|") Then ' 出错语句

            MessageBox.Show(rg_val.Value.ToString)

        End If 

    Next

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