FileSelectPopup errors out

[ASIC_LabRat]

Runtime error window:

NON-FATAL RUN-TIME ERROR: "c:\...\CVI\Includes\excel_datafile_stuff.c", line 1004, col 13, thread id 9752: Function FileSelectPopup: (return value == -180 [0xffffff4c]). The dialog cannot be displayed in a thread whose concurrency model is multithread apartment (MTA)

Code function call:

char currentFilename[MAX_PATHNAME_LEN] = {"C:\\Users\\Public\\Documents"};

char newFilename[MAX_PATHNAME_LEN];

...

FileSelectPopup (currentFilename, "*.xlsx", "*.xlsx;*.xls;*.txt;*.csv", "Select Data file",
VAL_SELECT_BUTTON, 0, 1, 1, 1, newFilename);

Windows10, CVI 2019

{userint.h}

#define MAX_PATHNAME_LEN 260 /* includes nul byte */

This code worked ok in CVI 2012 - CVI 2017 

[ASIC_LabRat]

Added this to "main"

int main (int argc, char *argv[])
{
if (InitCVIRTE (0, argv, 0) == 0)
return -1; /* out of memory */
if ((panelHandle = LoadPanel (0, "QMxxx.uir", PANEL)) < 0)
return -1;

if ((plotPanelHandle = LoadPanel (0, "QMxxx.uir", PLOT_PANEL)) < 0)
return -1;

panelHandle1 = NewPanel (1, "Excel Datafile Control", VAL_AUTO_CENTER, VAL_AUTO_CENTER, 180, 380); // setup save panel

... {other main declares...}

(new code!)

unsigned int threadStyle = COINIT_APARTMENTTHREADED;
//Valid values are COINIT_MULTITHREADED and COINIT_APARTMENTTHREADED.
CA_InitActiveXThreadStyleForCurrentThread (0, threadStyle);

(end of new code insert)
// Excell file control panel creation
excel_file_control_panel();
// end of excel file control panel creation

DisplayPanel (panelHandle);
RunUserInterface ();

... (to the end of main)

Forcing the thread style to "COINIT_APARTMENTTHREADED" appears to solve the RT error.

don't know why or what other issues will be broken from this change. 

ChipB.

[blakney]

FileSelectPopup must be run in a single threaded environment due to Windows limitation. If you are not running any multithreaded code, you will be fine. If your code is multithreaded, you must spin off a new thread and run FileSelectPopup in that thread (where that thread is in itself single threaded) and then return the filename to the main thread.