我的对象引用未设置为对象的实例

Question

当我点击保存按钮内的保存按钮时出现此错误 错误是

“对象引用未设置为对象的实例”

Protected Sub btnWizardFinish_Click(sender As Object, e As EventArgs)
    If (rdoAprovalList.SelectedIndex = 1) Then
        SaveConsideration(4)
    Else
        SaveConsideration(1)
    End If
End Sub

这是保存子，包含保存和更新数据库中 DocumentStatusID 字段中的值

Private Sub SaveConsideration(ByVal DocumentStatusID As Integer)
    Dim Conn As New SqlConnection(strConn)
    Dim cmd As New SqlCommand
    Try
        If ((txtProducerID.Text.Trim.Length = 9)) Then

            cmd.Connection = Conn
            cmd.CommandType = CommandType.StoredProcedure
            cmd.CommandText = "spConsiderationSaving"
            cmd.Parameters.AddWithValue("@libDocumentID", txtProducerID.Text)
            cmd.Parameters.AddWithValue("@ProducerComments", txtProducerComment.Text)
            cmd.Parameters.AddWithValue("@DocumentStatusID", DocumentStatusID)
            cmd.Parameters.AddWithValue("@ConProduceThai", chkConproduceThai.Checked)
            cmd.Parameters.AddWithValue("@ConProducePolicy", chkConProducePolicy.Checked)
            cmd.Parameters.AddWithValue("@ConProduceIP", chkConProduceIP.Checked)
            cmd.Parameters.AddWithValue("@ConProduceDanger", chkConProduceDanger.Checked)
            cmd.Parameters.AddWithValue("@ConProducePeople", chkConproducePeople.Checked)
            cmd.Parameters.AddWithValue("@ConProduceManage", chkConProduceManage.Checked)
            cmd.Parameters.AddWithValue("@ConProduceMade", chkConProduceMade.Checked)
            Conn.Open()
            Dim ResponseText As Integer = DirectCast(cmd.ExecuteScalar, Int32).ToString
            If (ResponseText = 1) Then
                lblResponseResult.Text = "<img src='../images/icons/message-boxes/confirmation.png' /> บันทึกลงฐานข้อมูลเรียบร้อยแล้ว"
                If (DocumentStatusID = 3) Then 'Goto next step
                    AlertRedirects("redirect", pnlHint.ClientID, 3, "Verification.aspx")
                Else
                    AlertBoxs("alert", pnlHint.ClientID, 2)
                End If
            End If
        Else
            Dim sb As New System.Text.StringBuilder()
            sb.Append("<script type = 'text/javascript'>")
            sb.Append("window.onload=function(){")
            sb.Append("javascript:history.back();return false;")
            sb.Append("};")
            sb.Append("</script>")
            ClientScript.RegisterClientScriptBlock(Me.GetType(), "back", sb.ToString())
        End If
    Catch ex As Exception
        Response.Write("Error Save: " & ex.Message)
    Finally
        Conn.Close()

    End Try

End Sub

我认为这是参考某物的问题

Answer 1

什么是错误，请说明。您发布的代码似乎有两个语法错误

  Dim ResponseText As Integer = DirectCast(cmd.ExecuteScalar, Int32).ToString
        If (ResponseText = 1) 

您正在为 ResponseText 分配一个字符串值，它是一个整数 第二个是如果条件应该有像If (ResponseText == 1)这样的双等号，因为它不是用于赋值的单等号