C# Word 文件生成完整實戰：Microsoft Office Interop 與 OpenXML 雙引擎架構指南

在企業級應用中，動態生成 Word 文件是常見需求。本文深度解析兩大主流方案：`Microsoft.Office.Interop.Word` (需安裝 Office) 與 `OpenXML SDK` (無需 Office、效能優、伺服器適用)，提供完整架構與生產級程式碼。

方案一：Office Interop (相容性佳、功能全、需 Office)

透過 COM 自動化操作 Word 應用程式，支援所有 Word 功能但需授權、啟動慢、不適合伺服器端大量生成。

企業級封裝：範本驅動、資料繫結、資源管理

using Microsoft.Office.Interop.Word;
using System.Runtime.InteropServices;

public class WordInteropGenerator : IDisposable {
    private Application _app;
    private Document _doc;
    private bool _disposed;
    
    public WordInteropGenerator(bool visible = false) {
        _app = new Application {
            Visible = visible,
            DisplayAlerts = WdAlertLevel.wdAlertsNone
        };
    }
    
    /// 
從範本建立文件
    public void CreateFromTemplate(string templatePath, object data) {
        object missing = Type.Missing;
        _doc = _app.Documents.Add(templatePath, ref missing, ref missing, ref missing);
        BindData(data);
    }
    
    /// 
建立空白文件
    public void CreateBlank() {
        object missing = Type.Missing;
        _doc = _app.Documents.Add(ref missing, ref missing, ref missing, ref missing);
    }
    
    /// 
資料繫結：書籤、合併列表、內容控制項
    private void BindData(object data) {
        var props = data.GetType().GetProperties();
        
        foreach (var prop in props) {
            string name = prop.Name;
            object value = prop.GetValue(data);
            
            // 1. 書籤繫結
            if (_doc.Bookmarks.Exists(name)) {
                _doc.Bookmarks[name].Range.Text = value?.ToString() ?? "";
            }
            
            // 2. 合併列表 (MailMerge)
            // 需在範本設定合併欄位
        }
        
        // 3. 表格資料填充
        FillTables(data);
    }
    
    private void FillTables(object data) {
        // 實作表格填充邏輯
    }
    
    /// 
儲存文件
    public void SaveAs(string path, WdSaveFormat format = WdSaveFormat.wdFormatDocumentDefault) {
        object fileName = path;
        object fileFormat = format;
        object missing = Type.Missing;
        _doc.SaveAs2(ref fileName, ref fileFormat, ref missing, ref missing, 
            ref missing, ref missing, ref missing, ref missing, ref missing, 
            ref missing, ref missing, ref missing, ref missing, ref missing, 
            ref missing, ref missing);
    }
    
    /// 
轉 PDF
    public void ExportAsPdf(string path) {
        object fileName = path;
        object missing = Type.Missing;
        _doc.ExportAsFixedFormat2(
            OutputFileName: (string)fileName,
            ExportFormat: WdExportFormat.wdExportFormatPDF,
            OpenAfterExport: false,
            OptimizeFor: WdExportOptimizeFor.wdExportOptimizeForPrint,
            ExportRange: WdExportRange.wdExportAllDocument,
            Item: WdExportItem.wdExportDocumentContent,
            IncludeDocProps: true,
            KeepIRM: true,
            CreateBookmarks: WdExportCreateBookmarks.wdExportCreateWordBookmarks,
            DocStructureTags: true,
            BitmapMissingFonts: true,
            UseISO19005_1: false
        );
    }
    
    public void Dispose() {
        if (!_disposed) {
            try {
                _doc?.Close(false);
                _app?.Quit(false);
            } catch { }
            finally {
                // 強制釋放 COM 物件
                if (_doc != null) Marshal.ReleaseComObject(_doc);
                if (_app != null) Marshal.ReleaseComObject(_app);
                _doc = null;
                _app = null;
                GC.Collect();
                GC.WaitForPendingFinalizers();
            }
            _disposed = true;
        }
    }
}

// 使用範例
public void GenerateReport() {
    var data = new {
        Title = "月度銷售報表",
        Date = DateTime.Now.ToString("yyyy年MM月dd日"),
        Department = "業務部",
        Items = new[] {
            new { Product = "產品A", Qty = 100, Amount = 50000 },
            new { Product = "產品B", Qty = 200, Amount = 80000 }
        }
    };
    
    using (var gen = new WordInteropGenerator()) {
        gen.CreateFromTemplate(@"C:\Templates\ReportTemplate.dotx", data);
        gen.SaveAs(@"C:\Output\Report.docx");
        gen.ExportAsPdf(@"C:\Output\Report.pdf");
    }
}

方案二：OpenXML SDK (無需 Office、高效能、伺服器首選)

直接操作 `.docx` (OOXML) 封裝格式，純 .NET 程式碼、無 COM 開銷、執行緒安全、適合大量生成。

核心架構：Document -> Body -> Paragraph/Table -> Run -> Text

using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Wordprocessing;
using System.IO;

public class WordOpenXmlGenerator {
    
    /// 
建立文件
    public void CreateDocument(string outputPath, Action buildAction) {
        using (var doc = WordprocessingDocument.Create(outputPath, 
            DocumentFormat.OpenXml.WordprocessingDocumentType.Document)) {
            
            // 建立基本結構
            MainDocumentPart mainPart = doc.AddMainDocumentPart();
            mainPart.Document = new Document(new Body());
            
            // 執行建構邏輯
            buildAction(doc);
            
            mainPart.Document.Save();
        }
    }
    
    /// 
從範本建立 (複製並修改)
    public void CreateFromTemplate(string templatePath, string outputPath, 
        Action modifyAction) {
        File.Copy(templatePath, outputPath, true);
        using (var doc = WordprocessingDocument.Open(outputPath, true)) {
            modifyAction(doc);
        }
    }
    
    // === 輔助建構方法 ===
    
    public Paragraph AddParagraph(Body body, string text, string styleId = null, 
        JustificationValues alignment = JustificationValues.Left) {
        var p = new Paragraph();
        if (styleId != null) p.ParagraphProperties = new ParagraphProperties(
            new ParagraphStyleId { Val = styleId });
        p.ParagraphProperties = p.ParagraphProperties ?? new ParagraphProperties();
        p.ParagraphProperties.Justification = new Justification { Val = alignment };
        
        p.Append(new Run(new Text(text) { Space = SpaceProcessingModeValues.Preserve }));
        body.Append(p);
        return p;
    }
    
    public Table AddTable(Body body, int rows, int cols, string[] headers = null) {
        var table = new Table();
        
        // 表格屬性：邊框、寬度
        table.Append(new TableProperties(
            new TableBorders(
                new TopBorder { Val = BorderValues.Single, Size = 4 },
                new BottomBorder { Val = BorderValues.Single, Size = 4 },
                new LeftBorder { Val = BorderValues.Single, Size = 4 },
                new RightBorder { Val = BorderValues.Single, Size = 4 },
                new InsideHorizontalBorder { Val = BorderValues.Single, Size = 4 },
                new InsideVerticalBorder { Val = BorderValues.Single, Size = 4 }
            ),
            new TableWidth { Width = "5000", Type = TableWidthUnitValues.Pct }
        ));
        
        // 標題列
        if (headers != null) {
            var headerRow = new TableRow();
            foreach (var h in headers) {
                headerRow.Append(CreateCell(h, true));
            }
            table.Append(headerRow);
        }
        
        // 資料列
        for (int i = 0; i < rows; i++) {
            var row = new TableRow();
            for (int j = 0; j < cols; j++) {
                row.Append(CreateCell($"R{i}C{j}"));
            }
            table.Append(row);
        }
        
        body.Append(table);
        return table;
    }
    
    private TableCell CreateCell(string text, bool isHeader = false) {
        var cell = new TableCell();
        cell.Append(new TableCellProperties(
            new TableCellVerticalAlignment { Val = TableVerticalAlignmentValues.Center }
        ));
        var p = new Paragraph(
            new Run(new RunProperties(
                isHeader ? new Bold() : null,
                new RunFonts { Ascii = "微軟正黑體" }
            ),
            new Text(text) { Space = SpaceProcessingModeValues.Preserve }
        ));
        cell.Append(p);
        return cell;
    }
    
    public void FillTableData(Table table, IEnumerable