> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 基于事件的排行榜示例代码

> XBOX Live 基于事件的排行榜的 XSAPI 代码示例，包括前几名、分页以及围绕指定排名或玩家为中心。

本主题提供了基本排行榜显示、获取指定结果页、跳转到排行榜中的指定玩家以及获取下一页排行榜的示例代码。

本主题涵盖以下内容：

* [获取排行榜的顶部](#gttoal)
* [获取围绕指定排名的排行榜](#galaasr)
* [获取围绕指定玩家的排行榜](#galaasp)
* [获取下一页排行榜](#gtnpol)

<a id="gttoal" />

## 获取排行榜的顶部

使用 [XblLeaderboardGetLeaderboardAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardasync) 从排行榜顶部开始返回指定排行榜的值。查询由基于事件的用户统计信息支持的排行榜时，请务必将 `queryType` 字段设置为 `XblLeaderboardQueryType::UserStatBacked`。

### 基本排行榜显示（Flat C API）

#### Flat C API

```cpp theme={null}
auto asyncBlock = std::make_unique<XAsyncBlock>();
asyncBlock->queue = queue;
asyncBlock->context = nullptr;
asyncBlock->callback = [](XAsyncBlock* asyncBlock)
{
    std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; // Take over ownership of XAsyncBlock*.
    size_t resultSize;
    HRESULT hr = XblLeaderboardGetLeaderboardResultSize(asyncBlock, &resultSize);

    if (SUCCEEDED(hr))
    {
        leaderboardBuffer.resize(resultSize);
        XblLeaderboardResult* leaderboard{};

        hr = XblLeaderboardGetLeaderboardResult(asyncBlock, resultSize, leaderboardBuffer.data(), &leaderboard, nullptr);

        if (SUCCEEDED(hr))
        {
            // Use XblLeaderboardResult in result.
            for (auto row = 0u; row < leaderboard->rowsCount; ++row)
            {
                std::stringstream rowText;
                rowText << leaderboard->rows[row].xboxUserId << "\t";

                for (auto column = 0u; column < leaderboard->rows[row].columnValuesCount; ++column)
                {
                    rowText << leaderboard->rows[row].columnValues[column] << "\t";
                }
            }
        }
    }
};

// Instantiate and configure the leaderboard query.
XblLeaderboardQuery leaderboardQuery = {}; 
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str()) 
leaderboardQuery.leaderboardName = leaderboardName.c_str(); 
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
// For more leaderboard query options, replace the 4-line code block 
// that precedes this comment as indicated in other examples.

HRESULT hr = XblLeaderboardGetLeaderboardAsync(
    xboxLiveContext,
    leaderboardQuery,
    asyncBlock.get());
if (SUCCEEDED(hr))
{
    // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* because the callback will take over ownership.
    // If the call fails, std::unique_ptr will keep ownership and delete XAsyncBlock*.
    asyncBlock.release();
}
```

有关详细信息，请参阅以下内容：

* [XAsyncBlock](/reference/system/xasync/structs/xasyncblock)
* [XblLeaderboardGetLeaderboardAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardasync)
* [XblLeaderboardGetLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardresult)
* [XblLeaderboardGetLeaderboardResultSize](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardresultsize)
* [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery)
* [XblLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardresult)

<a id="galaasr" />

## 获取围绕指定排名的排行榜

将上面基本排行榜查询（Flat C API）示例中实例化和配置排行榜查询的 4 行代码块替换为以下代码块，即可从排行榜查询中获取指定的结果页。

### 获取指定的结果页（C）

#### Flat C API

```cpp theme={null}
XblLeaderboardQuery leaderboardQuery = {};
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str());
leaderboardQuery.leaderboardName = leaderboardName.c_str();
leaderboardQuery.skipResultToRank = 100;
leaderboardQuery.maxItems = 100;
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
```

有关详细信息，请参阅 [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery)。

<a id="galaasp" />

## 获取围绕指定玩家的排行榜

将上面基本排行榜查询（Flat C API）示例中实例化和配置排行榜查询的 4 行代码块替换为以下代码块，即可获取围绕指定玩家的排行榜。

#### Flat C API

```cpp theme={null}
XblLeaderboardQuery leaderboardQuery = {};
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str());
leaderboardQuery.leaderboardName = leaderboardName.c_str();
leaderboardQuery.skipToXboxUserId = xboxUserId;
leaderboardQuery.maxItems = 100;
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
```

有关详细信息，请参阅 [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery)。

<a id="gtnpol" />

## 获取下一页排行榜

若要获取先前排行榜结果的下一页，请按照以下示例代码所示调用 [XblLeaderboardResultGetNextAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextasync)。

#### Flat C API

```cpp theme={null}
auto asyncBlock = std::make_unique<XAsyncBlock>();
asyncBlock->queue = queue;
asyncBlock->context = nullptr;
asyncBlock->callback = [](XAsyncBlock* asyncBlock)
{
    std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; // Take over ownership of XAsyncBlock*.
    size_t resultSize;
    HRESULT hr = XblLeaderboardResultGetNextResultSize(asyncBlock, &resultSize);

    if (SUCCEEDED(hr))
    {
        std::vector<char> buffer(resultSize, 0);
        XblLeaderboardResult* result{};

        hr = XblLeaderboardResultGetNextResult(asyncBlock, resultSize, buffer.data(), &result, nullptr);
        // Use result to read the leaderboard results.
    }
};

HRESULT hr = XblLeaderboardResultGetNextAsync(
    xboxLiveContext,
    leaderboardResult,
    maxItems,
    asyncBlock.get());
if (SUCCEEDED(hr))
{
    // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* because the callback will take over ownership.
    // If the call fails, std::unique_ptr will keep ownership and delete XAsyncBlock*.
    asyncBlock.release();
}
```

有关详细信息，请参阅以下内容：

* [XAsyncBlock](/reference/system/xasync/structs/xasyncblock)
* [XblLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardresult)
* [XblLeaderboardResultGetNextAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextasync)
* [XblLeaderboardResultGetNextResult](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextresult)
* [XblLeaderboardResultGetNextResultSize](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextresultsize)


## Related topics

- [基于事件的统计信息与排行榜示例代码](/zh-CN/services/xbox-services/player-data/stats-leaderboards/event-based/how-to/live-statslb-eb-howto-nav.md)
- [基于事件的统计信息和排行榜](/zh-CN/services/xbox-services/player-data/stats-leaderboards/event-based/live-statslb-eb-nav.md)
- [基于事件的排行榜概述](/zh-CN/services/xbox-services/player-data/stats-leaderboards/event-based/live-leaderboards-eb-overview.md)
- [基于事件的排行榜的门户配置](/zh-CN/services/xbox-services/player-data/stats-leaderboards/event-based/config/live-eb-leaderboards-portal.md)
- [标题管理的统计信息和排行榜示例代码](/zh-CN/services/xbox-services/player-data/stats-leaderboards/title-managed/how-to/live-statslb-tm-howto-nav.md)