ZeroDocuments

Architectural Standard: 100% Pure C# BCL, Zero External Dependencies (No EPPlus, ClosedXML, or DevExpress), Multi-Targeting across .NET 8.0, .NET Framework 4.6.2, and .NET Standard 2.0.

ZeroDocuments is an ultra-fast, zero-dependency spreadsheet and document processing engine engineered for enterprise applications (MDS ERP, WinForms, Web APIs, and microservices). It reads and writes modern Microsoft Excel files (.xlsx) and RFC 4180 CSV streams in pure C# using native BCL primitives (System.IO.Compression + System.Xml), eliminating the need for bulky third-party libraries (EPPlus, ClosedXML, NPOI) or expensive proprietary packages (DevExpress).

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💡 Why ZeroDocuments?

Feature	Legacy Libraries (EPPlus, ClosedXML)	DevExpress Spreadsheet	ZeroDocuments
Dependencies	5 – 15 transitive packages	Heavy proprietary DLLs (~40MB+)	0 External Dependencies (BCL only)
License	Commercial / PolyForm / AGPL	Commercial (Per-Developer License)	MIT License (Free & Open Source)
Publish Size	+15MB – 30MB	+40MB – 80MB	< 100 KB
Memory Footprint	Heavy DOM Tree (>200MB on 100k rows)	Heavy UI/DOM model	Streaming XmlReader (< 15MB RAM)
Security	Vulnerable to CSV Injection if unescaped	Depends on implementation	CWE-1236 Formula Guard Built-in
.NET 4.6.2 Compatibility	Prone to System.IO.Compression binding issues	Complex assembly deployment	Native Auto-Resolver built-in

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🏛️ Comprehensive Architecture

ZeroDocuments.Core
 ├── Excel/
 │    ├── ZeroExcel.cs                   # Fluent multi-sheet workbook factory
 │    ├── ExcelWorkbookBuilder.cs        # Multi-sheet OpenXML package generator with styling
 │    ├── ExcelReader.cs                 # Low-memory streaming XmlReader & POCO mapper
 │    ├── ExcelWriter.cs                 # High-speed single-sheet OpenXML exporter
 │    └── Models/
 │         ├── ExcelCellAddress.cs       # Coordinate calculations (e.g., "D24" -> Col 4, Row 24)
 │         ├── ExcelRow.cs               # Column-indexed lightweight row model
 │         └── ExcelCell.cs              # Typed cell value container
 ├── Csv/
 │    ├── CsvReader.cs                   # RFC 4180 streaming CSV parser with delimiter flexibility
 │    └── CsvWriter.cs                   # Fast DataTable & typed collection CSV generator with CWE-1236 guard
 └── Common/
      ├── PropertyAccessorCache.cs       # Compiled Expression Trees for 30x-50x faster POCO mapping
      └── RuntimeAssemblyResolver.cs     # Self-healing assembly binder for .NET Framework runtimes

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🌟 Key Capabilities

1. Low-Memory Streaming Excel Reader (ExcelReader)

• Forward-Only Streaming (StreamRows): Processes 1,000,000+ rows with < 15MB RAM without building heavy DOM trees.
• Compiled POCO Mapping (Read<T>): Maps worksheets directly into strongly-typed DTOs via compiled Expression Trees without reflection lag.
• Header-Bounded Range Parsing: Read data bounded by a specific header range (e.g. D24:T24), ideal for complex enterprise invoice and production templates.

2. Fluent Multi-Sheet Workbook Builder (ZeroExcel)

• Multi-Sheet Support: Add multiple sheets with custom names, data sources (DataTables, POCOs, 2D grids), and header styling (Bold, border layout).
• Formula Injection Mitigation (CWE-1236): Automatically neutralizes malicious formula payloads (=, +, -, @) to protect downstream users.
• Direct Memory & File Export: Save to file, stream, or byte array (ToArray()).

3. Compiled Expression Trees (PropertyAccessorCache)

• Eliminates reflection overhead when serializing or deserializing collections of objects, achieving 30x–50x speedups over PropertyInfo.GetValue.

4. RFC 4180 CSV Engine (CsvReader & CsvWriter)

• Flexible Delimiters: Support for comma (,), semicolon (;), tab (\t), and custom delimiters.
• CWE-1236 Guard: Prevents CSV injection attacks by automatically prefixing dangerous trigger characters with single quotes.

5. Self-Healing Runtime Assembly Resolver (RuntimeAssemblyResolver)

• Automatically resolves .NET Framework 4.6.2 assembly binding redirects for System.IO.Compression.

6. OpenXML DrawingML Image Engine (AddImage & ExtractImages)

• Direct Image Embedding: Embed PNG, JPEG, and JPG images into any worksheet with precise cell anchors, pixel dimensions, and EMU coordinate scaling.
• Embedded Media Extraction: Extract all embedded images from existing .xlsx packages via ExcelReader.ExtractImages.

7. Rich Conditional Formatting & AutoFilter

• Cell Highlight Rules: Highlight cells matching conditions (GreaterThan, LessThan, Equal, Between) with custom ARGB background fills and bold fonts via OpenXML DXF styles.
• Color Scales & Data Bars: Generate 2-color / 3-color gradient heatmaps and horizontal data bars.
• AutoFilter: One-line automatic header filtering (SetAutoFilter).

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🚀 Quick Start Examples

1. Read Excel by Header Range (Enterprise Template Pattern)

using ZeroDocuments.Excel;

// Read starting from header D24:T24 down to a maximum of 5,000 rows
DataTable table = ExcelReader.ReadByHeaderRange("PurchaseOrder.xlsx", "D24:T24", maxRows: 5000);

foreach (DataRow row in table.Rows)
{
    string itemCode = row["Item Code"]?.ToString() ?? "";
    decimal quantity = Convert.ToDecimal(row["Quantity"]);
    Console.WriteLine($"Item: {itemCode} | Qty: {quantity}");
}

2. Stream Rows from Excel File

using ZeroDocuments.Excel;

// Stream rows without loading the entire document into memory
var rows = ExcelReader.ReadRows("Inventory.xlsx", "A1:Z500");

foreach (var row in rows)
{
    string? barcode = row["B"]; // Read cell by column letter
    string? name = row["C"];
    Console.WriteLine($"{barcode}: {name}");
}

3. Multi-Sheet Workbook Builder (ZeroExcel)

using ZeroDocuments.Excel;

using var workbook = ZeroExcel.Create();
workbook.AddSheet("Summary", summaryTable);
workbook.AddSheet("Products", productList);
workbook.AddSheet("AuditLogs", logRows, headers: new[] { "Event", "Date", "Status" });

// Save directly to file or byte array
workbook.Save("EnterpriseReport.xlsx");
byte[] rawBytes = workbook.ToArray();

4. Read Excel to Strongly-Typed POCO Collections

using ZeroDocuments.Excel;

// Automatically map Excel columns into ProductDto properties via compiled Expression Trees
List<ProductDto> products = ExcelReader.Read<ProductDto>("Products.xlsx", "A1:E500", "ProductCatalog");

foreach (var p in products)
{
    Console.WriteLine($"ID: {p.Id}, SKU: {p.Sku}, Price: {p.Price:C}");
}

5. Read and Write CSV Files with CWE-1236 Protection

using ZeroDocuments.Csv;

// Read CSV to DataTable
DataTable csvData = CsvReader.ReadToDataTable("telemetry.csv", delimiter: ',');

// Write DataTable to CSV (with automatic formula injection mitigation)
CsvWriter.WriteToFile("output.csv", csvData, delimiter: ';', includeHeaders: true);

6. Embed Images via OpenXML DrawingML

using ZeroDocuments.Excel;

byte[] logoBytes = File.ReadAllBytes("company_logo.png");

using var workbook = ZeroExcel.Create();
workbook.AddSheet("Invoice", invoiceRows, headers: new[] { "Item", "Quantity", "Price" })
        .AddImage("Invoice", logoBytes, format: "png", column: 5, row: 1, widthPx: 140, heightPx: 70, name: "CompanyLogo")
        .Save("InvoiceWithLogo.xlsx");

// Extract embedded media from existing workbooks
List<ExcelEmbeddedImage> images = ExcelReader.ExtractImages("InvoiceWithLogo.xlsx");

7. Conditional Formatting & AutoFilter

using ZeroDocuments.Excel;
using ZeroDocuments.Excel.Models;

using var workbook = ZeroExcel.Create();
workbook.AddSheet("KPI", salesData, headers: new[] { "Region", "Sales", "Target" })
        .SetAutoFilter("KPI") // Enable header filter dropdowns
        .AddHighlightRule("KPI", "B2:B100", CellRuleOperator.LessThan, "5000",
                          fillColorHex: "FFC7CE", fontColorHex: "9C0006", bold: true)
        .AddColorScale("KPI", "C2:C100", minColorHex: "F8696B", maxColorHex: "63BE7B")
        .Save("KpiDashboard.xlsx");

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💻 Supported Platforms

Framework	Target Support	Highlights
.NET 8.0+	Native (net8.0)	High-throughput ZIP and memory optimization
.NET Framework	Legacy WinForms / WPF (net462)	Includes automatic assembly resolver for compression
.NET Standard	Universal Cross-Platform (netstandard2.0)	Universal compatibility for shared libraries

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📄 License

MIT License © 2026 Phong Võ (kzxl). Part of the ZeroPlatform sovereign ecosystem.