打印预览为空

Question

这里是我的代码：

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 

我试图预览和打印在vb.net 用户需要点击“打印预览”在我的datagridview的项目按钮在打印文档之前查看文档，但是当我点击该按钮时，它只显示空白页面。我如何使datagridview中的记录出现在我的预览页面中？

Answer 1

我删除了Dim dgv作为新的DataGridView并替换为当前DataGridView的名称。