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DPI_HOSTING_BEHAVIOR enumeration (windef.h)

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Identifies the DPI hosting behavior for a window. This behavior allows windows created in the thread to host child windows with a different DPI_AWARENESS_CONTEXT

Syntax

typedef enum DPI_HOSTING_BEHAVIOR {
  DPI_HOSTING_BEHAVIOR_INVALID = -1,
  DPI_HOSTING_BEHAVIOR_DEFAULT = 0,
  DPI_HOSTING_BEHAVIOR_MIXED = 1
} ;

Constants

 
DPI_HOSTING_BEHAVIOR_INVALID
Value: -1
Invalid DPI hosting behavior. This usually occurs if the previous SetThreadDpiHostingBehavior call used an invalid parameter.
DPI_HOSTING_BEHAVIOR_DEFAULT
Value: 0
Default DPI hosting behavior. The associated window behaves as normal, and cannot create or re-parent child windows with a different DPI_AWARENESS_CONTEXT.
DPI_HOSTING_BEHAVIOR_MIXED
Value: 1
Mixed DPI hosting behavior. This enables the creation and re-parenting of child windows with different DPI_AWARENESS_CONTEXT. These child windows will be independently scaled by the OS.

Remarks

DPI_HOSTING_BEHAVIOR enables a mixed content hosting behavior, which allows parent windows created in the thread to host child windows with a different DPI_AWARENESS_CONTEXT value. This property only effects new windows created within this thread while the mixed hosting behavior is active. A parent window with this hosting behavior is able to host child windows with different DPI_AWARENESS_CONTEXT values, regardless of whether the child windows have mixed hosting behavior enabled.

This hosting behavior does not allow for windows with per-monitor DPI_AWARENESS_CONTEXT values to be hosted by windows with DPI_AWARENESS_CONTEXT values of system or unaware.

To avoid unexpected outcomes, a thread's DPI_HOSTING_BEHAVIOR should be changed to support mixed hosting behaviors only when creating a new window which needs to support those behaviors. Once that window is created, the hosting behavior should be switched back to its default value.

Enabling mixed hosting behavior will not automatically adjust the thread's DPI_AWARENESS_CONTEXT to be compatible with legacy content. The thread's awareness context must still be manually changed before new windows are created to host such content.

Requirements

Requirement Value
Minimum supported client Windows 10, version 1803 [desktop apps only]
Minimum supported server Windows Server 2016 [desktop apps only]
Header windef.h

See also

GetThreadDpiHostingBehavior

GetWindowDpiHostingBehavior

SetThreadDpiHostingBehavior