Question

我有一个for循环，它显示了最后一项。我想获取所有项目并用作存储过程的参数。有一个基本原因，为什么它只显示最后一项？

Dim Flipper As String
For x As Integer = 0 To EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles().Count - 1
        Flipper = EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles(x).Name

    Next

Stored Proc:
Select * From myTable Inner Join myOtherTalbe ON myTable.Id = myOtherTable.Id Where RoleId = @RoleId

VB CodeBehind:
Dim strConnection As String = "myDataSource"
        Dim con As New SqlConnection(strConnection)
        Dim cmd As New SqlCommand("mainForumA", con)
        cmd.CommandType = CommandType.StoredProcedure
        'params here if needed
        cmd.Parameters.Add(New SqlParameter("@RoleId", Flippers))
        con.Open()
        Dim ds = New DataSet()
        Dim da = New SqlDataAdapter(cmd)
        da.Fill(ds)

        cdcatalog.DataSource = ds
        cdcatalog.DataBind()
        con.Close()

如果我只有一个角色，那就没问题，但如果有多个角色，我需要：

Select * From myTable Inner Join myOtherTalbe ON myTable.Id = myOtherTable.Id Where RoleId = @RoleId1 Or RoleId = @RoleId2, etc

Answer 1

您需要以逗号分隔的字符串，并在sql文本中使用In运算符。

Dim Flippers As New List(Of String)
For x As Integer = 0 To EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles().Count - 1
    Flippers.Add(EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles(x).Name)
Next
Dim values As String = String.Join(Flippers.ToArray, ",") 

Dim sqlText = "Select * From table Where Role In (" & values & ")"

Answer 2

正如上面的回复所说，你没有用Flipper做任何事情。您可以尝试将名称添加到列表中，然后绑定它。另外，我会将CustomerRoles存储在列表中，而不是每次都解析IWorkContext。它将帮助您提高可读性和可能性。

 Dim Flipper As String
    Dim names As New List(Of String)
    For x As Integer = 0 To EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles().Count - 1
            Flipper = EngineContext.Current.Resolve(Of IWorkContext)().CurrentCustomer.CustomerRoles(x).Name
            names.Add(Flipper)
        Next

    ListView1.DataSource = names
    ListView1.DataBind()

For Loop仅显示最后一项

2 个答案: