vb.net 中的打印预览为空

Posted 2023-02-16

【中文标题】vb.net 中的打印预览为空

【英文标题】：Print Preview in vb.net is empty

【发布时间】：2012-12-03 12:25:18

【问题描述】：

这是我的代码：

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

我正在尝试在 vb.net 中预览和打印我的 datagridview 中的项目 用户需要在打印之前单击“打印预览”按钮来查看文档，但是当我单击该按钮时，它只显示一个空白页面。如何使 datagridview 中的记录出现在我的预览页面中？

【参考方案1】：

我删除了 Dim dgv As New DataGridView 并替换为当前 DataGridView 的名称。