// Allocates a new string on the unmanaged heap,
// and stores the pointer so we can free it later.
private IntPtr MakeNewString(string s,
TaskDialogNativeMethods.TASKDIALOG_ELEMENTS element)
{
IntPtr newStringPtr = Marshal.StringToHGlobalUni(s);
updatedStrings[(int)element] = newStringPtr;
return(newStringPtr);
}
// Checks to see if the given element already has an
// updated string, and if so,
// frees it. This is done in preparation for a call to
// MakeNewString(), to prevent
// leaks from multiple updates calls on the same element
// within a single native dialog lifetime.
private void FreeOldString(TaskDialogNativeMethods.TASKDIALOG_ELEMENTS element)
{
int elementIndex = (int)element;
if (updatedStrings[elementIndex] != IntPtr.Zero)
{
Marshal.FreeHGlobal(updatedStrings[elementIndex]);
updatedStrings[elementIndex] = IntPtr.Zero;
}
}
private void UpdateTextCore(string s, TaskDialogNativeMethods.TASKDIALOG_ELEMENTS element)
{
AssertCurrentlyShowing();
FreeOldString(element);
SendMessageHelper(
TaskDialogNativeMethods.TASKDIALOG_MESSAGES.TDM_SET_ELEMENT_TEXT,
(int)element,
(long)MakeNewString(s, element));
}
