发票管理系统全流程构建：选型→功能开发→测试→上线（附 30 天落地计划表）

// 发票实体类
public class Invoice
{
    public int Id { get; set; }
    public string InvoiceCode { get; set; } // 发票代码
    public string InvoiceNumber { get; set; } // 发票号码
    public DateTime IssueDate { get; set; } // 开票日期
    public decimal Amount { get; set; } // 金额
    public string BuyerName { get; set; } // 购方名称
    public string SellerName { get; set; } // 销方名称
    public InvoiceType Type { get; set; } // 发票类型
    public InvoiceStatus Status { get; set; } // 发票状态
}

// 发票类型枚举
public enum InvoiceType
{
    VATSpecial, // 增值税专用发票
    VATNormal,  // 增值税普通发票
    Electronic  // 电子发票
}

// 数据库上下文
public class InvoiceContext : DbContext
{
    public DbSet Invoices { get; set; }
    
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // 配置实体关系和数据约束
        modelBuilder.Entity()
            .HasIndex(i => new { i.InvoiceCode, i.InvoiceNumber })
            .IsUnique();
    }
}

// 发票验真服务接口
public interface IInvoiceVerificationService
{
    Task VerifyAsync(Invoice invoice);
}

// 发票验真服务实现
public class TaxPlatformVerificationService : IInvoiceVerificationService
{
    private readonly HttpClient _httpClient;
    
    public TaxPlatformVerificationService(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }
    
    public async Task VerifyAsync(Invoice invoice)
    {
        // 构建验真请求
        var request = new VerificationRequest
        {
            InvoiceCode = invoice.InvoiceCode,
            InvoiceNumber = invoice.InvoiceNumber,
            IssueDate = invoice.IssueDate,
            Amount = invoice.Amount
        };
        
        // 调用税务平台API
        var response = await _httpClient.PostAsJsonAsync(
            "api/verify", request);
        
        if (!response.IsSuccessStatusCode)
        {
            throw new InvoiceVerificationException("验真服务调用失败");
        }
        
        var result = await response.Content.ReadFromJsonAsync();
        return MapToResult(result);
    }
    
    private VerificationResult MapToResult(VerificationResponse response)
    {
        // 将API响应映射为验真结果
        return new VerificationResult
        {
            IsValid = response.Status == "VALID",
            VerificationTime = DateTime.Now,
            Message = response.Message
        };
    }
}