VB.NET中DataTable转HTML打印：含页眉/纸张设置等需求求助

1. 优化HTML生成代码（含打印样式） #

直接生成带完整打印规则的HTML，包含标题页眉、发票号、总计，同时指定A5横向、页面自适应：

Private Function DataTableToPrintHtml(dt As DataTable, title As String, invoiceNo As String) As String
    ' 计算金额总计
    Dim totalAmount As Decimal = 0
    For Each row As DataRow In dt.Rows
        If Not IsDBNull(row("金额")) Then
            totalAmount += Convert.ToDecimal(row("金额"))
        End If
    Next

    ' 构建HTML字符串，内嵌打印专用CSS
    Dim htmlBuilder As New StringBuilder()
    htmlBuilder.AppendLine("<!DOCTYPE html>")
    htmlBuilder.AppendLine("<html>")
    htmlBuilder.AppendLine("<head>")
    htmlBuilder.AppendLine("<meta charset='utf-8'>")
    htmlBuilder.AppendLine("<title>" & title & "</title>")
    htmlBuilder.AppendLine("<style>")
    ' 通用显示样式
    htmlBuilder.AppendLine("body { font-family: 微软雅黑, Arial; margin: 0; padding: 10px; }")
    htmlBuilder.AppendLine(".header { text-align: center; margin-bottom: 20px; }")
    htmlBuilder.AppendLine(".header h1 { margin: 0; font-size: 18px; }")
    htmlBuilder.AppendLine(".invoice-no { text-align: right; margin-bottom: 15px; font-size: 14px; }")
    htmlBuilder.AppendLine("table { width: 100%; border-collapse: collapse; margin-top: 10px; }")
    htmlBuilder.AppendLine("th, td { border: 1px solid #000; padding: 8px; text-align: center; font-size: 12px; }")
    htmlBuilder.AppendLine("th { background-color: #f0f0f0; font-weight: bold; }")
    htmlBuilder.AppendLine(".total-row { font-weight: bold; font-size: 14px; background-color: #f5f5f5; }")
    ' 打印专用样式（媒体查询）
    htmlBuilder.AppendLine("@media print {")
    htmlBuilder.AppendLine("    @page {")
    htmlBuilder.AppendLine("        size: A5 landscape; /* A5横向设置 */")
    htmlBuilder.AppendLine("        margin: 1cm; /* 页边距 */")
    htmlBuilder.AppendLine("    }")
    htmlBuilder.AppendLine("    body { padding: 0; }")
    htmlBuilder.AppendLine("    .header, .invoice-no { page-break-inside: avoid; }")
    htmlBuilder.AppendLine("    table { page-break-inside: auto; }")
    htmlBuilder.AppendLine("    tr { page-break-inside: avoid; page-break-after: auto; }")
    htmlBuilder.AppendLine("}")
    htmlBuilder.AppendLine("</style>")
    htmlBuilder.AppendLine("</head>")
    htmlBuilder.AppendLine("<body>")
    ' 标题页眉
    htmlBuilder.AppendLine("<div class='header'>")
    htmlBuilder.AppendLine("<h1>" & title & "</h1>")
    htmlBuilder.AppendLine("</div>")
    ' 发票号页眉
    htmlBuilder.AppendLine("<div class='invoice-no'>")
    htmlBuilder.AppendLine("发票号: " & invoiceNo)
    htmlBuilder.AppendLine("</div>")
    ' 数据表格
    htmlBuilder.AppendLine("<table>")
    ' 表头
    htmlBuilder.AppendLine("<thead>")
    htmlBuilder.AppendLine("<tr>")
    For Each col As DataColumn In dt.Columns
        htmlBuilder.AppendLine("<th>" & col.ColumnName & "</th>")
    Next
    htmlBuilder.AppendLine("</tr>")
    htmlBuilder.AppendLine("</thead>")
    ' 表体数据行
    htmlBuilder.AppendLine("<tbody>")
    For Each row As DataRow In dt.Rows
        htmlBuilder.AppendLine("<tr>")
        For Each col As DataColumn In dt.Columns
            htmlBuilder.AppendLine("<td>" & If(IsDBNull(row(col)), "", row(col).ToString()) & "</td>")
        Next
        htmlBuilder.AppendLine("</tr>")
    Next
    ' 总计行
    htmlBuilder.AppendLine("<tr class='total-row'>")
    htmlBuilder.AppendLine("<td colspan='" & (dt.Columns.Count - 1) & "' style='text-align: right;'>总计:</td>")
    htmlBuilder.AppendLine("<td>" & totalAmount.ToString("C2") & "</td>")
    htmlBuilder.AppendLine("</tr>")
    htmlBuilder.AppendLine("</tbody>")
    htmlBuilder.AppendLine("</table>")
    htmlBuilder.AppendLine("</body>")
    htmlBuilder.AppendLine("</html>")

    Return htmlBuilder.ToString()
End Function

2. 打印预览与直接打印实现 #

使用WebBrowser控件加载生成的HTML，利用其内置的打印功能完成需求：

步骤1：添加WebBrowser控件 #

在窗体设计器中拖入一个WebBrowser控件，可设置Visible = False隐藏显示。

步骤2：打印预览代码 #

Private Sub btnPrintPreview_Click(sender As Object, e As EventArgs) Handles btnPrintPreview.Click
    ' 替换为你的DataTable、标题、发票号
    Dim htmlContent As String = DataTableToPrintHtml(yourDataTable, "销售明细单", "INV-20240520-001")
    WebBrowser1.DocumentText = htmlContent
    ' 等待文档加载完成后触发预览
    AddHandler WebBrowser1.DocumentCompleted, AddressOf WebBrowser_DocumentCompleted_Preview
End Sub

Private Sub WebBrowser_DocumentCompleted_Preview(sender As Object, e As WebBrowserDocumentCompletedEventArgs)
    WebBrowser1.ShowPrintPreviewDialog()
    ' 移除事件避免重复触发
    RemoveHandler WebBrowser1.DocumentCompleted, AddressOf WebBrowser_DocumentCompleted_Preview
End Sub

步骤3：直接打印代码 #

Private Sub btnPrint_Click(sender As Object, e As EventArgs) Handles btnPrint.Click
    Dim htmlContent As String = DataTableToPrintHtml(yourDataTable, "销售明细单", "INV-20240520-001")
    WebBrowser1.DocumentText = htmlContent
    AddHandler WebBrowser1.DocumentCompleted, AddressOf WebBrowser_DocumentCompleted_Print
End Sub

Private Sub WebBrowser_DocumentCompleted_Print(sender As Object, e As WebBrowserDocumentCompletedEventArgs)
    ' 直接打印（不弹出对话框）
    WebBrowser1.Print()
    RemoveHandler WebBrowser1.DocumentCompleted, AddressOf WebBrowser_DocumentCompleted_Print
End Sub

关键说明 #

• 打印规则控制：通过@media print和@page强制指定A5横向纸张、页边距，确保打印参数生效。
• 页面自适应：表格设为width:100%，内容会自动适配A5横向页面宽度。
• 分页优化：用page-break-inside: avoid避免页眉、数据行被分页截断。
• 总计计算：遍历DataTable统计金额，最后在表格底部添加加粗总计行。

内容的提问来源于stack exchange，提问作者user22579796