interface ICoreWebView2_19

interface ICoreWebView2_19
  : public ICoreWebView2_18

This interface is an extension of ICoreWebView2_18 that manages memory usage target level.

Summary

Members	Descriptions
get_MemoryUsageTargetLevel	Gets the MemoryUsageTargetLevel property.
put_MemoryUsageTargetLevel	An app may set MemoryUsageTargetLevel to indicate desired memory consumption level of WebView.

Applies to

Product	Introduced
WebView2 Win32	1.0.1823.32
WebView2 Win32 Prerelease	1.0.1905

Members

get_MemoryUsageTargetLevel

Gets the MemoryUsageTargetLevel property.

public HRESULT get_MemoryUsageTargetLevel(COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL * value)

put_MemoryUsageTargetLevel

An app may set MemoryUsageTargetLevel to indicate desired memory consumption level of WebView.

public HRESULT put_MemoryUsageTargetLevel(COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL value)

Scripts will not be impacted and continue to run. This is useful for inactive apps that still want to run scripts and/or keep network connections alive and therefore could not call TrySuspend and Resume to reduce memory consumption. These apps can set memory usage target level to COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_LOW when the app becomes inactive, and set back to COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_NORMAL when the app becomes active. It is not necessary to set CoreWebView2Controller's IsVisible property to false when setting the property. It is a best effort operation to change memory usage level, and the API will return before the operation completes. Setting the level to COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_LOW could potentially cause memory for some WebView browser processes to be swapped out to disk in some circumstances. It is a best effort to reduce memory usage as much as possible. If a script runs after its related memory has been swapped out, the memory will be swapped back in to ensure the script can still run, but performance might be impacted. Therefore, the app should set the level back to COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_NORMAL when the app becomes active again. Setting memory usage target level back to normal will not happen automatically. An app should choose to use either the combination of TrySuspend and Resume or the combination of setting MemoryUsageTargetLevel to low and normal. It is not advisable to mix them. Trying to set MemoryUsageTargetLevel while suspended will be ignored. The TrySuspend and Resume methods will change the MemoryUsageTargetLevel. TrySuspend will automatically set MemoryUsageTargetLevel to low while Resume on suspended WebView will automatically set MemoryUsageTargetLevel to normal. Calling Resume when the WebView is not suspended would not change MemoryUsageTargetLevel.

void ViewComponent::ToggleMemoryUsageTargetLevel()
{
    wil::com_ptr<ICoreWebView2_19> webView;
    webView = m_webView.try_query<ICoreWebView2_19>();
    CHECK_FEATURE_RETURN_EMPTY(webView);
    COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL memory_target_level =
        COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_NORMAL;
    CHECK_FAILURE(webView->get_MemoryUsageTargetLevel(&memory_target_level));
    memory_target_level = (memory_target_level == COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_LOW)
                              ? COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_NORMAL
                              : COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_LOW;
    CHECK_FAILURE(webView->put_MemoryUsageTargetLevel(memory_target_level));
    MessageBox(
        nullptr,
        (memory_target_level == COREWEBVIEW2_MEMORY_USAGE_TARGET_LEVEL_LOW)
            ? L"MemoryUsageTargetLevel is set to LOW."
            : L"MemoryUsageTargetLevel is set to NORMAL.",
        L"MemoryUsageTargetLevel change", MB_OK);
}