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How to use the MQL function MessageBox to Open a Trade

How do I open a messagebox with a question if I would like to open or cancel the trade before opening the trade ?

The MQL function “MessageBox” is available in the VTS Toolbox and can be used for this. It’s not as easy as it should be because I did not include the constant values needed for selection in the current version of VTS (4.0.0.78). I’ll be sure to include the values in the next release of VTS so that they will be available for easy selection. For now, I’ll provide the values here, and we just have to manually enter them when we configure the MQL function MessageBox.

First, we have the values used to determine what buttons are shown on the MessageBox. This value is entered in the “flags” parameter of MessageBox. Mostly we’ll want to use MB_OKCANCEL. This will display the familar OK and Cancel buttons on the message box.

Constant	Value	Description
MB_OK	0x00000000	Message window contains only one button: OK. Default
MB_OKCANCEL	0x00000001	Message window contains two buttons: OK and Cancel
MB_ABORTRETRYIGNORE	0x00000002	Message window contains three buttons: Abort, Retry and Ignore
MB_YESNOCANCEL	0x00000003	Message window contains three buttons: Yes, No and Cancel
MB_YESNO	0x00000004	Message window contains two buttons: Yes and No
MB_RETRYCANCEL	0x00000005	Message window contains two buttons: Retry and Cancel
MB_CANCELTRYCONTINUE	0x00000006	Message window contains three buttons: Cancel, Try Again, Continue

Next, we need have the values that are returned from the MessageBox after the user clicks. We will want to check for this value in a VTS Logic element.

For this example, we’ll check for IDOK – this means the user clicked OK.

Constant	Value	Description
IDOK	1	“OK” button has been pressed
IDCANCEL	2	“Cancel” button has been pressed
IDABORT	3	“Abort” button has been pressed
IDRETRY	4	“Retry” button has been pressed
IDIGNORE	5	“Ignore” button has been pressed
IDYES	6	“Yes” button has been pressed
IDNO	7	“No” button has been pressed
IDTRYAGAIN	10	“Try Again” button has been pressed
IDCONTINUE	11	“Continue” button has been pressed

To start, get the MessageBox function from the VTS ToolBox:

Connect the MessageBox function to the True output of the Logic Element that checks for your trade signal. So if your trade signal is True, the MessageBox function will execute and display a message that allows you to choose OK or Cancel. Then connect another Logic after the MessageBox function that checks the value of what was clicked. Connect the fnOpenTrade function to the True output so the trade is opened if you select OK.

This is how the MQL programming MessageBox function is configured:

This is how the Logic that checks for the value of the MessageBox is configured:

So for now, you’ll have to manually enter the values MB_OK and MB_OKCANCEL, but in the next version of VTS, I’ll add the selection values to the pulldown menus to make it easier. I’ll also make a short video showing how to build and run the EA.

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