Question

我正在为我遇到的问题寻求帮助。我在一个文件夹中有多个文本文件。该文件夹可以有一个＆＃34;无限制＆＃34;其中包含大量文本文件，但通常为2-150个文件 http://gyazo.com/5f314d1ca374abf9f813914609dd931d（此图片+以下图片，由于缺乏声誉而无法嵌入）

然后每个文件包含一个＆＃34;无限制＆＃34; （虽然通常为0-20行）其中的数据量。第1行是＆＃34;测试号码＆＃34;第2行是＆＃34;测试结果＆＃34; - 如上图所示

我的数据网格视图中有3列（用户名，测试编号，测试结果） - 如上图所示

在下面运行我的代码时;添加到数据网格视图的第一个记录完美地工作，但第二个（或第一个之后的任何记录）发生错误： http://gyazo.com/0d492b97d918853e62c55ee314f3f181（图片）或错误消息：

＆＃34; System.InvalidOperationException：集合已经属于a DataGridView控件。此操作不再有效。在 System.Windows.Forms.DataGridViewCellCollection.Add（DataGridViewCelldataGridViewCell）在SpellingBee.TeacherMultiResults.TeacherMultiResults_Load（对象发件人，EventArgs e）＆＃34;

DGVRow.Cells.Add(DGVCell) 'add cell to row

上发生此错误

我不想做的一件事是改变我的任何文本文件/文件夹结构，即使我知道它目前是低效的存储空间。

如何修复此错误？我使用VB.net（Visual Studios 2013）

如果您需要更多信息，请直接询问

非常感谢。

Imports System.Windows.Forms
Imports System.IO

Public Class TeacherMultiResults

    Dim AmountOfFiles
    Dim LineCount As Integer = 0
    Dim FileName As IO.FileInfo
    Dim DGVRow As New DataGridViewRow
    Dim DGVCell As DataGridViewCell
    Dim Username As String = ""
    Dim TestNumber As Integer = 0
    Dim TestResult As Integer = 0

    Private Sub TeacherMultiResults_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Dim directory As New IO.DirectoryInfo(LoadForm.CurrentDirectory & "\UserResults\") 'selects directory
        Dim FileNames As IO.FileInfo() = directory.GetFiles()
        Dim Files As IO.FileInfo

        For Each Files In FileNames 'list the names of all files in the specified directory
            Username = Files.ToString
            Username = (Username.Substring(0, Username.Length - 4)) 'removes the .txt from the name

            Try
                LineCount = File.ReadAllLines(LoadForm.CurrentDirectory & "\UserResults\" & Username & ".txt").Length 'amount of lines in file
                If LineCount > 1 Then
                    Dim Information As New System.IO.StreamReader(LoadForm.CurrentDirectory & "\UserResults\" & Username & ".txt") 'opens file
                    LineCount = LineCount / 2 'halfs line count
                    For i = 0 To LineCount - 1
                        TestNumber = Information.ReadLine() 'reads line to variable
                        TestResult = Information.ReadLine() 'reads line to variable
                        i = i + 1 'adds one to i

                        DGVCell = New DataGridViewTextBoxCell 'create a new DGV text box cell
                        DGVCell.Value = Username 'add value to DGV text box cell
                        DGVRow.Cells.Add(DGVCell) 'add cell to row

                        DGVCell = New DataGridViewTextBoxCell 'create a new DGV text box cell
                        DGVCell.Value = TestNumber 'add value to DGV text box cell
                        DGVRow.Cells.Add(DGVCell) 'add cell to row

                        DGVCell = New DataGridViewTextBoxCell 'create a new DGV text box cell
                        DGVCell.Value = TestResult 'add value to DGV text box cell
                        DGVRow.Cells.Add(DGVCell) 'add cell to row

                        DGV_MultiResults.Rows.Add(DGVRow) 'add row to DGV

                    Next
                    Information.Close() 'Close read
                End If

            Catch ex As Exception 'if file won't read
                MsgBox(ex.ToString) 'show error
                Exit Try
            End Try 'end of try

        Next 'end of files

    End Sub

我希望有人可以帮助我解决这个问题，我知道解决这个问题相当简单，尽管我似乎找不到错误的解决方案！

非常感谢，托比。

Answer 1

使用DataGridView时，通常更容易构建一个对象列表，然后使用内置的数据绑定功能将其绑定到DGV。

对于您的示例，它看起来像这样：

' Read the files, build objects as you go and add them to a list
Dim lst = New List(Of TeacherMultiResults)

' Replace this part with your file reading code...
Dim t1 = New TeacherMultiResults With {.Username = "Bob", .TestNumber = 1, .TestResult = 75}
lst.Add(t1)
Dim t2 = New TeacherMultiResults With {.Username = "Rick", .TestNumber = 1, .TestResult = 85}
lst.Add(t2)
Dim t3 = New TeacherMultiResults With {.Username = "Zoe", .TestNumber = 1, .TestResult = 95}
lst.Add(t3)

' Bind the list to the DataGridView
Dim bindList = New BindingList(Of TeacherMultiResults)(lst)
Dim bindSrc = New BindingSource

bindSrc.DataSource = bindList
grid.DataSource = bindSrc

您的网格应显示列表中的每个项目。

将记录（行/列）添加到DataGridView; Collection已经属于DataGridView控件VB.NET

1 个答案: