VB.NET Excel文件未与虚拟数据网格视图连接

Question

我正试图在VB.NET应用程序中编写一个模块，但它无法正常工作。我正在尝试创建一个数据网格视图，并加载一个excel文件到其中。然而，excel没有加载到其中。

下方的代码

Imports Microsoft.Office
Imports Microsoft.Office.Interop
Imports System.Data.OleDb
Imports System.Net.Mail
Module m_IslsHpPtSplit
Dim UploadFilePath As String
Dim UploadFileName As String
Dim dgv1 As DataGridView
Dim dgv2 As DataGridView
Public Sub LoadFile()
    dgv1 = New DataGridView
    dgv2 = New DataGridView
    Try
        Dim filedialog As OpenFileDialog = New OpenFileDialog()
        Dim path As String
        filedialog.Title = "Select file"
        filedialog.InitialDirectory = "Desktop"
        filedialog.RestoreDirectory = True
        If filedialog.ShowDialog() = Windows.Forms.DialogResult.OK Then
            path = filedialog.FileName
        Else
            path = Nothing
        End If
        UploadFilePath = filedialog.FileName
        UploadFileName = System.IO.Path.GetFileName(filedialog.FileName)
        Dim dtSheet1 As New DataTable
        If Not path = Nothing Then
            Using cn As New System.Data.OleDb.OleDbConnection
                Dim Builder As New OleDbConnectionStringBuilder With _
                    { _
                        .DataSource = path, _
                        .Provider = "Microsoft.ACE.OLEDB.12.0" _
                    }
                Builder.Add("Extended Properties", "Excel 12.0; IMEX=1;HDR=Yes;")
                cn.ConnectionString = Builder.ConnectionString
                cn.Open()
                Using cmd As OleDbCommand = New OleDbCommand With {.Connection = cn}
                    cmd.CommandText = "SELECT * FROM [FNAC$]"
                    Dim dr As System.Data.IDataReader = cmd.ExecuteReader
                    dtSheet1.Load(dr)
                    dgv1.DataSource = dtSheet1
                End Using
            End Using
            MessageBox.Show(dgv1.RowCount)
            MessageBox.Show("Done")
        End If
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try
    SplitFile()
End Sub 'LoadFile

之后，我需要进行一些计算等，但线

MessageBox.Show(dgv1.RowCount)

实际返回0。excel文件中有316行。如何获取数据以坚持使用新的dgv？

Answer 1

我认为问题源于没有实际将dgv1添加到任何控件集合（数据源已附加，但实际上没有创建要显示的行）。如果你使用MessageBox.Show(dtSheet1.Rows.Count)，你可能会注意到一个计数证明数据正在被读入。我在Messagebox.Show(dgv1.RowCount)之前添加了Form1.Controls.Add(dgv1)，并生成了一个正确的计数。