1. 使用Virtualize组件来显示表格并启用虚拟滚动：

    
     
        
@item.Key
        
@item.Value
    

2. 使用JavaScriptInterop来调用JavaScript方法实现定位特定键值和检测可见项：

@inject IJSRuntime jsRuntime

Scroll to Item3

@code {
    Dictionary items = new Dictionary
    {
        { "Item1", "Value1" },
        { "Item2", "Value2" },
        { "Item3", "Value3" },
        { "Item4", "Value4" },
        //...
    };

    async Task ScrollToItem()
    {
        string key = "Item3";
        int index = 0;
        foreach (var item in items)
        {
            if (item.Key == key)
            {
                break;
            }
            index++;
        }

        await jsRuntime.InvokeVoidAsync("scrollToItem", index);
    }
}

3. 在JavaScript文件中实现滚动到指定项和检测可见项的方法：

function scrollToItem(index) {
    const itemList = document.getElementById("itemList");
    const itemHeight = 30;
    const scrollTop = index * itemHeight;
    itemList.scrollTop = scrollTop;

    const visibleItems = getVisibleItems(itemList);
    console.log(visibleItems);
}

function getVisibleItems(container) {
    const scrollTop = container.scrollTop;
    const itemHeight = 30;
    const startIndex = Math.floor(scrollTop / itemHeight);
    const endIndex = Math.min(Math.ceil((scrollTop + container.clientHeight) / itemHeight), container.childElementCount);

    const visibleItems = [];
    for (let i = startIndex;