从 sql db 填充列表框，其中 3 个字段满足文本框值

Question

我正在尝试从 sql 数据库返回列表框中的行。我只希望返回 3 个字段与文本框值匹配的行。目前，如果在 3 个文本框中的任何一个中键入任何内容，列表框将返回所有行。如果没有输入任何内容，则不会显示任何内容（该部分是预期/正确的行为）。 我的代码是：

  Private Sub tireselect_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    m_cn.ConnectionString = "Data Source=localhost;Initial Catalog=tires;Integrated Security=True"
    m_cn.Open()
    'Dim con As New SqlConnection()
    'Dim cmd As String = "Select brand, model, width, aspect, rim, retail from dbo.tires"
    Dim sqltext = "SELECT [ID] ,[brand] ,[model] ,[cost] ,[retail] ,[width] ,[aspect] ,[rim] FROM [tires].[dbo].[tires]"
    Using sqlCon = New SqlConnection("Data Source=localhost;Initial Catalog=tires;Integrated Security=True")
        sqlCon.Open()


        Dim cmd = New SqlCommand(sqltext, sqlCon)
        cmd.Parameters.AddWithValue("@tirewidth", (Int(TireLookup.txtWidth.Text)))
        cmd.Parameters.AddWithValue("@tireaspect", (Int(TireLookup.txtAspect.Text)))
        cmd.Parameters.AddWithValue("@tirerim", (Int(TireLookup.txtRim.Text)))
        cmd.ExecuteNonQuery()
    End Using

    Dim m_da As New SqlDataAdapter("SELECT [ID] ,[brand] ,[model] ,[cost] ,[retail] ,[width] ,[aspect] ,[rim] FROM [tires].[dbo].[tires] where [width]=tirelookup.txtwidth.text AND [aspect]=tirelookup.txtwidth.text AND [rim]=tirelookup.txtrim.text", m_cn)
    Dim myDataSet As New DataSet()
    m_da.Fill(myDataSet, "dbo.tires")
    Dim myDataTable As DataTable = myDataSet.Tables(0)
    Dim tempRow As DataRow
    For Each tempRow In myDataTable.Rows
        ListBox1.Items.Add(tempRow("brand"))
        ListBox2.Items.Add(tempRow("model"))
        ListBox3.Items.Add(tempRow("width") & " / " & tempRow("aspect") & " / " & tempRow("rim"))
        ListBox4.Items.Add("$ " & tempRow("retail") & "   Tire ID=" & (tempRow("ID") - 1))
    Next
End Sub

Answer 1

你需要像这样改变你的谓词：

  where [width]=@tirewidth 
  AND [aspect]=@tireaspect
  AND [rim]=@tirerim