vb.net列表框和sql

Question

我有4个列表框，我检查，其中的内容去弥补放入sql语句的变量。这很好。问题是我必须检查所有的框。如果我留下任何框out sql语句不起作用。 我尝试添加“”到列表框但这不起作用，它看起来很乱。有一种解决方法。很多感谢吉姆这里是我的代码：

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.Odbc
Imports System.Data.DataTable
Public Class Form1

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As      System.EventArgs) Handles MyBase.Load

    End Sub

     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As  System.EventArgs) Handles Button1.Click
    Dim con As New OleDb.OleDbConnection
    Dim dbProvider As String
    Dim dbSource As String
    Dim ds As New DataSet
    Dim tables As DataTableCollection = ds.Tables
    Dim source1 As New BindingSource()
    Dim da As New OleDb.OleDbDataAdapter
    Dim sql As String

    Dim aa As String = authorList.Text
    Dim bb As String = publisherList.Text
    Dim cc As String = yearpublishedList.Text
    Dim dd As String = genreList.Text

    dbProvider = "PROVIDER=Microsoft.ACE.OLEDB.12.0;"
    dbSource = "Data Source =C:\Documents and Settings\james\Desktop\Authors.accdb"
    con.ConnectionString = dbProvider & dbSource
    con.Open()
    sql = "SELECT * FROM books WHERE author = '" & aa & "' AND publisher = '" & bb &  "' AND yearpublished = '" & cc & "' AND genre = '" & dd & "' "


    da = New OleDb.OleDbDataAdapter(sql, con)
    da.Fill(ds, "Authors")

    Dim view1 As New DataView(tables(0))
    source1.DataSource = view1
    DataGridView1.DataSource = view1
    DataGridView1.Refresh()

    'MsgBox("OPEN FOR LUNCH")
    'MsgBox("CLOSED FOR THE DAY")
    con.Close()
 End Sub
End Class

Answer 1

您正在将复选框解析为字符串，因此当您这样做时，您会得到：

1,2,3,4,5,6,7

如果您没有选中一个复选框，它将如下所示：

1,2,3，，5,6,7

所以SQL会破解

有几种方法可以解决这个问题，所以我不打算尝试一下。 但是，这应该有希望向你解释发生了什么以及它为什么会发生，所以你可以继续修复