// 假设我们有一个ComboBox控件comboBox1和一个DataGridView控件dataGridView1

// 初始化时加载数据
private void Form1_Load(object sender, EventArgs e)
{
    // 绑定ComboBox数据源
    comboBox1.DataSource = GetCategories(); // 获取分类数据
    comboBox1.DisplayMember = "CategoryName"; // 显示字段
    comboBox1.ValueMember = "CategoryID"; // 值字段
    
    // 初始加载所有数据到DataGridView
    dataGridView1.DataSource = GetAllProducts();
}

// ComboBox选择变化事件
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (comboBox1.SelectedValue != null)
    {
        int selectedCategoryId = (int)comboBox1.SelectedValue;
        
        // 根据选择的分类ID过滤产品数据
        var filteredProducts = GetProductsByCategory(selectedCategoryId);
        dataGridView1.DataSource = filteredProducts;
    }
}

// 示例数据获取方法
private List<Category> GetCategories()
{
    // 这里应该是从数据库或服务获取数据
    return new List<Category>
    {
        new Category { CategoryID = 1, CategoryName = "电子产品" },
        new Category { CategoryID = 2, CategoryName = "办公用品" },
        new Category { CategoryID = 3, CategoryName = "家居用品" }
    };
}

private List<Product> GetAllProducts()
{
    // 获取所有产品数据
    return new List<Product>
    {
        new Product { ProductID = 1, ProductName = "笔记本电脑", CategoryID = 1 },
        new Product { ProductID = 2, ProductName = "智能手机", CategoryID = 1 },
        new Product { ProductID = 3, ProductName = "打印机", CategoryID = 2 },
        new Product { ProductID = 4, ProductName = "椅子", CategoryID = 3 }
    };
}

private List<Product> GetProductsByCategory(int categoryId)
{
    // 根据分类ID获取产品数据
    var allProducts = GetAllProducts();
    return allProducts.Where(p => p.CategoryID == categoryId).ToList();
}

// 示例数据模型类
public class Category
{
    public int CategoryID { get; set; }
    public string CategoryName { get; set; }
}

public class Product
{
    public int ProductID { get; set; }
    public string ProductName { get; set; }
    public int CategoryID { get; set; }
}