EM_SETREADONLY message

Sets or removes the read-only style (ES_READONLY) of an edit control. You can send this message to either an edit control or a rich edit control.

wParam

Specifies whether to set or remove the ES_READONLY style. A value of TRUE sets the ES_READONLY style; a value of FALSE removes the ES_READONLY style.

lParam

This parameter is not used.

If the operation succeeds, the return value is nonzero.

If the operation fails, the return value is zero.

When an edit control has the ES_READONLY style, the user cannot change the text within the edit control.

To determine whether an edit control has the ES_READONLY style, use the GetWindowLong function with the GWL_STYLE flag.

Rich Edit: Supported in Microsoft Rich Edit 1.0 and later. For information about the compatibility of rich edit versions with the various system versions, see About Rich Edit Controls.

GetWindowLong