应用来自多个 checkboxList 的过滤器来过滤 VB.net 中的 ListView

Question

我有一个 web 应用程序，其中有 1000 个产品，因此需要有多个过滤器。我总共有 4 个复选框列表。现在我的问题是，如果我从任何 checkboxList 应用过滤器，那么它会检查查询中指定的所有列的 selected 值。我要的是下面这样

SELECT * FROM products WHERE price_rang IN ('selectedValueFromCheckBoxList1') And category IN ('selectedValueFromCheckBoxList2')

现在发生了什么

SELECT * FROM `products` WHERE price_range IN ('selectedValueFromCheckBoxList2') AND category IN ('selectedValueFromCheckBoxList2')

所以在这个查询中假设如果我 select 值首先来自 checkboxList2 然后对于两个列它都采用该值并且结果不显示。

下面是我的过滤流程代码

Private Sub getResult()
        Dim constr As String = ConfigurationManager.ConnectionStrings("conio").ConnectionString
        Dim query As String = "select * from products"

        Dim condition As String = String.Empty
        For Each price As ListItem In priceFilter.Items
            condition += If(price.Selected, String.Format("'{0}',", price.Value), String.Empty)
        Next

        For Each sub_category As ListItem In category.Items
            condition += If(sub_category.Selected, String.Format("'{0}',", sub_category.Value), String.Empty)
        Next

        If Not String.IsNullOrEmpty(condition) Then
            condition = String.Format(" WHERE price_range IN ({0}) and sub_category IN ({0})", condition.Substring(0, condition.Length - 1))
        End If

        Using con As New MySqlConnection(constr)
            Using cmd As New MySqlCommand(query & condition)
                Using sda As New MySqlDataAdapter(cmd)
                    cmd.Connection = con
                    Using dt As New DataTable()
                        sda.Fill(dt)
                        products.DataSource = dt
                        products.DataBind()
                    End Using
                End Using
            End Using
        End Using
    End Sub

Answer 1

这是一个选项，如果您只对选中的项目感兴趣。

Public Function buildWhereClause() As String

        Dim query As String = "select * from products"
        Dim joiner As String = " "

        Dim condition As String = String.Empty
        Dim priceCondition As String = String.Empty

        For i = 0 To priceFilter.Items.Count - 1

            If priceFilter.Items(i).Selected Then
                Dim price As String = priceFilter.Items(i).ToString
                priceCondition = String.Concat(priceCondition, joiner, String.Format("'{0}'", price))
                If joiner = " " Then joiner = ", "
            End If
        Next

        Dim categoryCondition As String = String.Empty
        joiner = " "

        For i = 0 To categoryFilter.Items.Count - 1
            If categoryFilter.Items(i).Selected Then
                Dim category As String = categoryFilter.Items(i).ToString
                categoryCondition = String.Concat(categoryCondition, joiner, String.Format("'{0}'", category))
                If joiner = " " Then joiner = ", "
            End If
        Next

        Dim whereClause As String = String.Empty
        joiner = " where "
        If Not String.IsNullOrEmpty(priceCondition) Then
            whereClause = String.Concat(whereClause, joiner, String.Format(" price_range IN ({0})", priceCondition)) ' and sub_category IN ({0})", condition.Substring(0, condition.Length - 1))
            joiner = " and "
        End If

        If Not String.IsNullOrEmpty(categoryCondition) Then
            whereClause = String.Concat(whereClause, joiner, String.Format(" sub_category in ({0})", categoryCondition))
            joiner = " and "
        End If

        Return String.Concat(query, whereClause)

    End Function

应用来自多个 checkboxList 的过滤器来过滤 VB.net 中的 ListView

Apply filters from multiple checkboxList to filter ListView in VB.net

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