VB.NET & ASP.NET MVC导入CSV文件并在表格显示数据问题

问题根源 #

1. 数据存储错误：你在Controller中使用的TSetList是单个字符串数组，循环读取CSV每行数据时会反复覆盖数组内容，最终ViewData("transactions")仅保留了CSV的最后一行数据。
2. 视图渲染错误：直接用@Html.Raw(ViewData("transactions"))输出数组，ASP.NET MVC会直接输出数组的类型字符串（如System.String[]），不会自动生成表格行结构，导致表格无法正常展示数据。

解决方案步骤 #

1. 创建交易数据模型类

先定义一个类来封装每行交易数据，让数据结构更清晰：

Public Class Transaction
    Public Property SortCode As String
    Public Property AccountNumber As String
    Public Property AccountName As String
    Public Property Reference As String
    Public Property RTI As String
    Public Property Value As String
End Class

2. 修改Controller代码

将单个字符串数组替换为List(Of Transaction)，循环读取每行数据时添加到列表中，最后把整个列表传入ViewData：

Function Create() As ActionResult
    Return View()
End Function

<HttpPost()>
Function Create(upload As HttpPostedFileBase) As ActionResult
    Try
        If upload IsNot Nothing Then
            Dim _skiplines As Integer = 3
            Dim _posSortcode As Integer = 0
            Dim _posAccountNumber As Integer = 1
            Dim _posAccountName As Integer = 2
            Dim _posReference As Integer = 4
            Dim _posRTI As Integer = 999
            Dim _posValue As Integer = 3

            ' 初始化存储所有交易数据的列表
            Dim transactions As New List(Of Transaction)

            If upload.ContentLength > 0 Then
                Using reader = New System.IO.StreamReader(upload.InputStream)
                    ' 跳过指定行数
                    If _skiplines > 0 Then
                        For Counter = 1 To _skiplines
                            reader.ReadLine()
                        Next
                    End If

                    ' 循环读取每行数据
                    Do While Not reader.EndOfStream
                        Dim LineArray = Split(reader.ReadLine, ",")
                        Dim trans As New Transaction

                        ' 为当前交易对象赋值
                        trans.SortCode = If(_posSortcode <> 999, LineArray(_posSortcode), "")
                        trans.AccountNumber = If(_posAccountNumber <> 999, LineArray(_posAccountNumber), "")
                        trans.AccountName = If(_posAccountName <> 999, LineArray(_posAccountName), "")
                        trans.Reference = If(_posReference <> 999, LineArray(_posReference), "")
                        trans.RTI = If(_posRTI <> 999, LineArray(_posRTI), "")
                        trans.Value = If(_posValue <> 999, LineArray(_posValue), "")

                        ' 将当前交易添加到列表
                        transactions.Add(trans)
                    Loop
                    ViewData("transactions") = transactions
                    reader.Close()
                End Using
                ViewBag.Message = "Completed With " & transactions.Count.ToString()
            End If
        Else
            ViewBag.Message = "No File Found"
        End If
    Catch ex As Exception
        ViewBag.Error = ex.Message.ToString
    End Try
    Return View()
End Function

3. 修改View代码

在视图中遍历ViewData里的交易列表，动态生成表格行：

@Using (Html.BeginForm("Create", "File", Nothing, FormMethod.Post, New With {.enctype = "multipart/form-data"}))
@<div class="form-horizontal">
    <h4>Instructor</h4>
    <hr />

    <div class="form-group">
        <div class="col-md-10">
            <input type="file" id="ImportFile" name="upload" />
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>
    </div>
</div>
@ViewBag.Message
@If ViewBag.Error IsNot Nothing Then
    @<div class="alert alert-danger">@ViewBag.Error</div>
End If
End Using

<table class="table">
<thead>
    <tr>
        <th>Sort Code</th>
        <th>Account Number</th>
        <th>Account Name</th>
        <th>Reference</th>
        <th>RTI</th>
        <th>Value</th>
    </tr>
</thead>
<tbody id="helpRowBody">
    @If ViewData("transactions") IsNot Nothing Then
        Dim transactions = CType(ViewData("transactions"), List(Of Transaction))
        For Each trans In transactions
            @<tr>
                <td>@trans.SortCode</td>
                <td>@trans.AccountNumber</td>
                <td>@trans.AccountName</td>
                <td>@trans.Reference</td>
                <td>@trans.RTI</td>
                <td>@trans.Value</td>
            </tr>
        Next
    End If
</tbody>
</table>

内容的提问来源于stack exchange，提问作者PeteN