例外:VB.NET&中没有为一个或多个必需参数提供任何值. MS-访问数据库 [英] Exception: No value given for one or more required parameters in VB.NET & MS-ACCESS DB

问题描述

我使用库存系统.代码错误

I work with an Inventory System. I have an error on my code, it says

没有为一个或多个必需参数提供值.

No value given for one or more required parameters.

，错误被抛出到cmd.ExecuteNonQuery().这是什么意思?有人能帮我吗?顺便说一句，此代码用于扣除数据库中的物料数量.对不起，我的英语不好.

and the error was thrown to cmd.ExecuteNonQuery(). What does it mean? can someone help me? By the way this code is for deducting Item Quantity on Database. Sorry for my bad English.

con.Open()
Dim sqlQry As String = "UPDATE [tbl_Stocks] 
                        SET [Quantity] = [Quantity] - @QU 
                        WHERE Products='" & lbPro.Text & "'"
Using cmd As New OleDbCommand(sqlQry, con)
    cmd.Parameters.AddWithValue("@QU", lbQuan.Text)
    cmd.ExecuteNonQuery()
    con.Close()
    MsgBox("Save Successfully!")
End Using

推荐答案

我看不到任何缺陷.尝试使用这种替代方法(稍作调整即可通过参数发送两个输入)

I don't see any flaw. Try this substitute(a little tweak sending both inputs via parameter)

con.Open()
Dim sqlQry As String = "UPDATE [tbl_Stocks] SET [Quantity] = [Quantity] - @QU " &
                       "WHERE Products=@prod"
Using cmd As New OleDbCommand(sqlQry, con)
    cmd.Parameters.AddWithValue("@QU", lbQuan.Text)
    cmd.Parameters.AddWithValue("@prod", lbPro.Text)
    cmd.ExecuteNonQuery()
    con.Close()
    MsgBox("Save Successfully!")
End Using

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