字段掩码

<ph type="x-smartling-placeholder">

在 Google Ads API 中，更新是使用字段掩码完成的。字段掩码列出 您打算随更新而更改的所有字段，以及任何指定的字段 字段掩码范围外的其他字词，即使发送到服务器，也会被忽略。

FieldMaskUtil

推荐使用我们的内置字段掩码生成字段掩码 实用程序，它可让您通过修改的对象（而不是 从零开始构建它们

以下是一个更新广告系列的示例：

// Update campaign by setting its status to paused, and "Search network" to false.
Campaign campaignToUpdate = new Campaign()
{
    ResourceName = ResourceNames.Campaign(customerId, campaignId),
    Status = CampaignStatus.Paused,
    NetworkSettings = new NetworkSettings()
    {
        TargetSearchNetwork = false
    }
};

// Create the operation.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaignToUpdate,
    UpdateMask = FieldMasks.AllSetFieldsOf(campaignToUpdate)
};

// Update the campaign.
MutateCampaignsResponse response = campaignService.MutateCampaigns(
    customerId.ToString(), new CampaignOperation[] { operation });

首先，我们创建一个空的 Campaign 对象。然后，我们设置其资源名称 API 会准确知道我们要更新的广告系列

该示例对广告系列使用 FieldMasks.AllSetFieldsOf 方法 自动生成列举所有已设置字段的字段掩码。然后，您可以 将返回的掩码直接传递给 update 调用。

有时，您可能需要处理现有对象，并更新几个字段。 在这种情况下，您可以按如下方式修改代码：

Campaign existingCampaign;

// Obtain existingCampaign from elsewhere.
...

// Create a new campaign based off the existing campaign for update.
Campaign campaignToUpdate = new Campaign(existingCampaign);

// Update campaign by setting its status to paused, and "Search network" to
// false.
campaignToUpdate.Status = CampaignStatus.Paused;
campaignToUpdate.NetworkSettings = new NetworkSettings()
{
    TargetSearchNetwork = false
}

// Create the operation.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaignToUpdate,
    UpdateMask = FieldMasks.FromChanges(existingCampaign, campaignToUpdate)
};

要从头开始创建字段掩码，您首先需要创建一个 FieldMask 对象，然后使用所需的全部字段的名称填充一个数组 最后将数组内容附加到字段掩码的 Path 字段。

FieldMask fieldMask = new FieldMask();
fieldMask.Paths.AddRange(new string[] { "status", "name" });

更新消息字段及其子字段

MESSAGE 字段可以包含子字段（例如 MaximizeConversions，其中包含三个： target_cpa_micros, cpc_bid_ceiling_micros 和 cpc_bid_floor_micros），也可以不将任何 （例如 ManualCpm）。

没有已定义子字段的消息字段

在更新未使用任何子字段定义的 MESSAGE 字段时，请使用 FieldMasks 以生成字段掩码，如上所述。

包含已定义子字段的消息字段

更新使用不包含子字段的子字段定义的 MESSAGE 字段时 因此您必须手动设置 将每个可变的 MESSAGE 子字段添加到 FieldMask，类似于 上面的示例，它从头开始创建字段掩码。

一个常见的例子是，在未设置任何选项的情况下更新广告系列的出价策略 新出价策略的字段。以下示例演示了如何 更新广告系列以使用 MaximizeConversions出价策略 而不必为出价策略设置任何子字段。

在本例中，使用 AllSetFieldsOf() 和 FromChanges() 方法 FieldMasks没有达到预期目标。

以下示例将生成包含以下内容的字段掩码： maximize_conversions。但是，Google Ads API 不允许这种行为 防止意外清除字段 FieldMaskError.FIELD_HAS_SUBFIELDS 错误。

// Creates a campaign with the proper resource name and an empty
// MaximizeConversions field.
Campaign campaign = new Campaign()
{
    ResourceName = ResourceNames.Campaign(customerId, campaignId),
    MaximizeConversions = new MaximizeConversions()
};

// Constructs an operation, using the FieldMasks' AllSetFieldsOf utility to
// derive the update mask. The field mask will include 'maximize_conversions`,
// which will produce a FieldMaskError.FIELD_HAS_SUBFIELDS error.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaign,
    UpdateMask = FieldMasks.AllSetFieldsOf(campaign)
};

// Sends the operation in a mutate request that will result in a
// FieldMaskError.FIELD_HAS_SUBFIELDS error because empty MESSAGE fields cannot
// be included in a field mask.
MutateCampaignsResponse response = campaignService.MutateCampaigns(
    customerId.ToString(), new CampaignOperation[] { operation });

以下示例演示了如何正确更新广告系列以使用 MaximizeConversions出价策略，但未设置任何子字段。

// Creates a Campaign object with the proper resource name.
Campaign campaign = new Campaign()
{
    ResourceName = ResourceNames.Campaign(customerId, campaignId),
};

// Creates a field mask from the existing campaign and adds all of the fields
// on the MaximizeConversions bidding strategy to the field mask. Because these
// fields are included in the field mask but excluded from the campaign object,
// the Google Ads API will set the campaign's bidding strategy to a
// MaximizeConversions object with none of its subfields set.
FieldMask fieldMask = FieldMasks.AllSetFieldsOf(campaign);
// Only include 'maximize_conversions.target_cpa_micros' in the field mask
// as it is the only mutable subfield on MaximizeConversions when used as a
// standard bidding strategy.
//
// Learn more about standard and portfolio bidding strategies here:
// https://developers.google.com/google-ads/api/docs/campaigns/bidding/assign-strategies
fieldMask.Paths.AddRange(new string[] {
    "maximize_conversions.target_cpa_micros",
});

// Creates an operation to update the campaign with the specified fields.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaign,
    UpdateMask = fieldMask
};

清除字段

某些字段是可以明确清除的。与上面的示例类似，您必须 明确地将这些字段添加到字段掩码中。例如，假设您有一个 广告系列，该广告系列采用的是MaximizeConversions出价策略，并且 “target_cpa_micros”字段的值大于 0。

系统会运行以下代码：不过，maximize_conversions.target_cpa_micros 因此也不会对 target_cpa_micros 字段：

// Creates a campaign with the proper resource name and a MaximizeConversions
// object with target_cpa_micros set to 0.
Campaign campaign = new Campaign()
{
    ResourceName = ResourceNames.Campaign(customerId, campaignId),
    MaximizeConversions = new MaximizeConversions()
    {
        TargetCpaMicros = 0
    }
};

// Constructs an operation, using the FieldMasks' AllSetFieldsOf utility to
// derive the update mask. However, the field mask will NOT include
// 'maximize_conversions.target_cpa_micros'.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaign,
    UpdateMask = FieldMasks.AllSetFieldsOf(campaign)
};

// Sends the operation in a mutate request that will succeed but will NOT update
// the 'target_cpa_micros' field because 'maximize_conversions.target_cpa_micros'
// was not included in the field mask.
MutateCampaignsResponse response = campaignService.MutateCampaigns(
    customerId.ToString(), new CampaignOperation[] { operation });

下一个示例演示了如何正确清除 target_cpa_micros 字段（MaximizeConversions 出价策略）。

// Creates a Campaign object with the proper resource name.
Campaign campaign = new Campaign()
{
    ResourceName = ResourceNames.Campaign(customerId, campaignId),
};

// Constructs a field mask from the existing campaign and adds the
// 'maximize_conversions.target_cpa_micros' field to the field mask, which will
// clear this field from the bidding strategy without impacting any other fields
// on the bidding strategy.
FieldMask fieldMask = FieldMasks.AllSetFieldsOf(campaign);
fieldMask.Paths.AddRange(new string[] {
    "maximize_conversions.target_cpa_micros",
});

// Creates an operation to update the campaign with the specified field.
CampaignOperation operation = new CampaignOperation()
{
    Update = campaign,
    UpdateMask = fieldMask
};

请注意，上面的示例确实适用于 在 Google Ads API 中定义为 optional protocol buffers。 但自从使用 target_cpa_micros 不是 optional 字段，则“不正确”示例不会更新 清除 target_cpa 字段。