打印預覽爲空

Question

這裏是我的代碼：

Imports System.Drawing 
Imports System.Drawing.Printing 
Imports System.Data 
Imports System.Data.OleDb 
Public Class Form3 
Dim dgv As New DataGridView() 
Dim print As New PrintDocument() 
Dim preview As New PrintPreviewDialog() 
Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    Dim con As New OleDbConnection("Provider=Microsoft.Jet.Oledb.4.0;Data Source=C:\Users\user\Documents\Inventory\InventoryLogin\InventoryLogin\Supplies.mdb") 
    Try 
     con.Open() 
     Dim sql As String 
     sql = "SELECT * From [product info]" 
     Dim adapter As New OleDbDataAdapter(sql, con) 
     Dim dt As New DataTable("product info") 
     adapter.Fill(dt) 

     preview.PrintPreviewControl.Zoom = 1 
     preview.Document = print 
     preview.Show() 

     AddHandler print.PrintPage, AddressOf print_PrintPage 

    Catch Ex As Exception 
     MessageBox.Show(Ex.Message) 
    End Try 

End Sub 

Protected Sub print_PrintPage(ByVal sender As Object, ByVal e As PrintPageEventArgs) 
    Dim ColumnCount As Integer = dgv.ColumnCount 
    Dim RowCount As Integer = dgv.RowCount 

    Dim CellTopPos As Integer = print.PrinterSettings.DefaultPageSettings.Margins.Top 

    For Row = 0 To RowCount - 2 

     Dim CellLeftPos As Integer = print.PrinterSettings.DefaultPageSettings.Margins.Left 

     For Cell = 0 To ColumnCount - 1 

      Dim CellValue As String = dgv.Rows(Row).Cells(Cell).Value.ToString() 
      Dim CellWidth = dgv.Rows(Row).Cells(Cell).Size.Width + 10 
      Dim CellHeight = dgv.Rows(Row).Cells(Cell).Size.Height 

      Dim Brush As New SolidBrush(Color.Black) 
      e.Graphics.DrawString(CellValue, New Font("tahoma", 10), Brush, CellLeftPos, CellTopPos) 
      e.Graphics.DrawRectangle(Pens.Black, CellLeftPos, CellTopPos, CellWidth, CellHeight) 

      CellLeftPos += CellWidth 
     Next 

     CellTopPos += dgv.Rows(Row).Cells(0).Size.Height 
    Next 

End Sub 
End Class 

我試圖預覽和打印在vb.net 用戶需要點擊「打印預覽」在我的datagridview的項目按鈕在打印文檔之前查看文檔，但是當我點擊該按鈕時，它只顯示空白頁面。我如何使datagridview中的記錄出現在我的預覽頁面中？

Answer 1

我刪除了Dim dgv作爲新的DataGridView並替換爲當前DataGridView的名稱。