错误：索引和长度必须指向字符串中的位置

Question

我在vb.net上遇到以下异常。我无法解决此错误：

Error 5: Index and length must refer to a location within the string.Parameter name: length.

这是我的代码：

Private Sub attemptedNumbersNew2(ByVal date_start As DateTime, ByVal date_end As DateTime, ByVal port As String, ByVal team As String)
        Dim con As New ADODB.Connection
        Dim recordS As New ADODB.Recordset
        Dim sql As String = "some query...."


        Try
            con.Open(connectStringA)
            recordS.Open(sql, con)
            If recordS.EOF Then
            Else
                Do While Not recordS.EOF
                    Dim temp As String
                    If name4number.Contains(lastAttempted) Then
                        temp = name4number.Item(lastAttempted)
                    Else
                        temp = lastAttempted
                    End If
                    If attemptedNames.Equals("NONE") Or attemptedNames.Equals("") Then
                        attemptedNames = temp
                    ElseIf Not temp.Equals("") Then
                        attemptedNames = attemptedNames & " - " & temp
                    End If
                    If agentsHashOffered.Contains(temp & "_" & team) Then
                        agentsHashOffered.Item(temp & "_" & team) = agentsHashOffered.Item(temp & "_" & team) + 1
                    Else
                        agentsHashOffered.Add(temp & "_" & team, 1)
                    End If
                    If recordS.Fields(2).Value >= oldDate Then
                        If answeringNumber.Equals("NONE") Then
                            answeringNumber = recordS.Fields(4).Value
                            If answeringNumber.Substring(0, 1).Equals("9") Then
                                answeringNumber = answeringNumber.Substring(1, 10)
                            End If
                            callDuration = -1
                        End If
                        disconnectionTime = recordS.Fields(3).Value

                    Else
                    End If

                    If attempted.Equals("NONE") Then
                        attempted = recordS.Fields(4).Value
                        If attempted.Substring(0, 1).Equals("9") Then
                            attempted = attempted.Substring(1, 10)
                        End If
                        attemptedCount = attemptedCount + 1
                        lastAttempted = attempted
                    Else
                        temp = recordS.Fields(4).Value
                        If temp.Substring(0, 1).Equals("9") Then
                            temp = temp.Substring(1, 10)
                        End If

                        attempted = attempted & "  -  " & temp
                        attemptedCount = attemptedCount + 1
                        lastAttempted = temp
                    End If
                    recordS.MoveNext()
                Loop
            End If
            con.Close()
            con = Nothing
            recordS = Nothing
        Catch ex As Exception
            MsgBox("Error #" & Err.Number & ": " & Err.Description)
        End Try
End Sub

前几天工作正常，但突然间我开始收到这个错误。

欢迎任何帮助 谢谢你提前