sql - 无法将 vb.net 项目与 Access 号进行比较

Question

编辑:对于遇到此问题的任何人，不要错过有关仅使用的提示参数，而不是将值直接插入到 SQL 查询中。

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我的 vb.net 项目遇到了一个大问题，我坚持了一个星期

我有一个组合框项目，我需要将它与 Access 号进行比较，这是我的数据库以检索一些信息，但我只是收到一个错误，无论我将我的组合框项目转换成什么格式，它都说我的数据类型不兼容用表达式

这是我的代码中的一个 SQL 查询:

Dim dt1 As New DataTable 

'This query select some itens from a row that match with the selected combobox number  

Dim find1 As New OleDb.OleDbDataAdapter("SELECT Product, Number," _ 
& " Customer, Quantity, ProductionDate, AskDay, Pack, Company FROM RegOPE" _ 
& " WHERE Number ='" & CInt(mycombobox.SelectedItem) & "'", cn)

'Ive tried SelectedItem, Item, Text, SelectedValue...  
'For conversion i tried parse, tryparse, conversion...  

cn.Open() 'Opens database connection  
find1.Fill(dt1)  <- I got the error here  
cn.Close() 'Close database connect  
mydatagrid.DataSource = dt1 'Show the result in datagridview  

Answer 1

数字标准应该没有引号

Dim find1 As New OleDb.OleDbDataAdapter("SELECT Product, Number, " _
                                      & "Customer, Quantity, ProductionDate, AskDay, Pack, Company FROM RegOPE " _
                                      & "WHERE Number =" & CInt(mycombobox.SelectedItem), cn)

但最好始终使用参数:

Dim comm = New OleDb.OleDbCommand("SELECT Product, Number, " _
                                      & "Customer, Quantity, ProductionDate, AskDay, Pack, Company FROM RegOPE " _
                                      & "WHERE Number =?", cn)

comm.Parameters.AddWithValue("unusedName", mycombobox.SelectedItem)

Dim find1 As New OleDb.OleDbDataAdapter(comm)