# ExcelMcp.ComInterop
**Low-level COM interop utilities for Excel automation by Sbroenne.**
## Overview
This library provides Excel-specific COM object lifecycle management and OLE message filtering. It's the foundation layer for ExcelMcp projects, handling STA threading, session management, and batch operations specifically for Excel COM automation.
**Note:** Despite the generic name "ComInterop", this library is Excel-specific and not intended for Word/PowerPoint/other Office applications.
## Features
- **STA Threading Management** - Ensures proper single-threaded apartment model for Excel COM objects
- **COM Object Lifecycle** - Automatic COM object cleanup and garbage collection
- **OLE Message Filtering** - Handles busy/rejected COM calls with retry logic using Polly
- **Excel Session Management** - Manages Excel.Application lifecycle safely
- **Batch Operations** - Efficient handling of multiple Excel operations in a single session
## Usage Example
```csharp
using Sbroenne.ExcelMcp.ComInterop;
// Use ExcelSession for safe Excel automation
await using var session = await ExcelSession.BeginAsync("path/to/workbook.xlsx");
await using var batch = await session.BeginBatchAsync();
await batch.ExecuteAsync<int>(async (ctx, ct) =>
{
// Access Excel workbook through ctx.Book
dynamic worksheets = ctx.Book.Worksheets;
dynamic sheet = worksheets.Item[1];
// Perform Excel operations
sheet.Name = "UpdatedSheet";
return 0;
});
await batch.Save();
```
## Key Classes
- **ExcelSession** - Manages Excel.Application lifecycle and workbook operations
- **ExcelBatch** - Groups multiple operations for efficient execution
- **ComUtilities** - Helper methods for COM object cleanup and safe property access
- **OleMessageFilter** - Implements retry logic for busy Excel instances
## Requirements
- Windows OS
- .NET 10.0 or later
- Microsoft Excel 2016+ installed
## Platform Support
- ✅ Windows x64
- ✅ Windows ARM64
- ❌ Linux (Excel COM not available)
- ❌ macOS (Excel COM not available)
