如何在Access数据库中插入空白数据 [英] How to insert blank data in access db

问题描述

大家好，

我有一个应用程序，在该应用程序中，我必须记录特定日期范围内完成的交易的报告
为此，我正在创建一个临时表，在表单加载期间将数据插入并读取其中，这是代码

Hi Everyone,

I have an application in which i have to take reports of the transaction done on particular date range
For this I am creating one temp table in which data is inserted and fetched during form load, here is the code

Dim InDate As String
               Dim OutDate As String
               Dim DtIn As Date
               Dim DtOut As Date
For i As Integer = 0 To ds.Tables(0).Rows.Count - 1
                        Regno = ds.Tables(0).Rows(i)(0).ToString()
                        barcode = ds.Tables(0).Rows(i)(1).ToString()
                        vehityp = ds.Tables(0).Rows(i)(2).ToString()
                        vehimodl = ds.Tables(0).Rows(i)(3).ToString()
                        InDate = ds.Tables(0).Rows(i)(4).ToString()
                        OutDate = ds.Tables(0).Rows(i)(5).ToString()
                        DtIn = DateTime.Parse(InDate)
                        DtOut = DateTime.Parse(OutDate)
                        diff = DtIn - DtOut
                        DiffD = diff.Days
                        DiffH = diff.Hours
                        DiffM = diff.Minutes
                        Try
                            sqlcmd = "Insert Into tmp ([RegistrationNo],[Barcode],[VehicleType],[VehicleModel] , [TranInDate], [TranOutDate], [OutDays], [OutHours], [OutMins]) Values ('" _
                            + Regno + "','" + barcode + "','" + vehityp + "','" + vehimodl + "', '" + InDate.ToString() + "', '" + OutDate.ToString() + "', " + DiffD.ToString() + ", " + DiffH.ToString() + ", " + DiffM.ToString() + ")"
                            cmd.CommandText = sqlcmd
                            cmd.ExecuteNonQuery()
                        Catch ex As Exception
                            MsgBox(ex.Message, "Messageinst")
                        End Try
                    Next

当我的InDate为空白时，显示错误为
无法将字符串识别为有效的DateTime"

谁能帮助我如何插入空白的InDate值

When My InDate is blank it is showing an error as
"String was not recognised as a valid DateTime"

Can anyone help me on how to insert the blank InDate value

推荐答案

这不是传递参数的最有效方法.使用参数化查询，这是一个示例:

http://www.vb-helper.com/howto_net_db_parameterized_query.html [

This is not the most efficient way of passing parameters. Use parameterized queries, here is an example:

http://www.vb-helper.com/howto_net_db_parameterized_query.html[^]

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