Gmap.Net Marker at incorrect position but when the map is zoomed the marker goes to right place

问题

I've a Windows Forms Application with a Gmap.Net controller, what I want to do is to add markers based on an outside sources that provides locations. The thing is that when I add a marker is initially drawn in an incorrect location, but after I zoom out it goes to the right place. So this is what I got so far:

My Map controller is declare to be located at Panama, Panama.

private void button2_Click(object sender, EventArgs e)
{    
    //Layer count is just a variable to add new OverLays with different names
    var markersOverlay = new GMapOverlay("markers" + layerCount);

    //Marker far away in Quebec, Canada just to check my point in discussion        
    var marker = new GMarkerGoogle(new PointLatLng(58.0032, -79.4957), GMarkerGoogleType.red_small);

    markersOverlay.Markers.Add(marker);
    gmap.Overlays.Add(markersOverlay);
    layerCount++;
}

So when I press the button what I got is this (have in mind that the map location it's set to be in Panama and the marker in Canada):

And when I zoom out, the marker goes to the correct position in Canada.

Why my marker is been drawn in Panama initially?

P.D: I already check this question but it doesn't resolve my problem because I need to be adding more than 1 marker and myMap.UpdateMarkerLocalPosition(marker) is not a solution for me.

回答1:

It's because you're adding the marker to the overlay that has not been added to the map's overlays. Try to switch the order of the statements as follows:

gmap.Overlays.Add(markersOverlay);
markersOverlay.Markers.Add(marker);

回答2:

add a first marker at lat,lon = 0,0. you can also make this marker invisible with setting its marker image as 1x1 pixel transparent png image. first element of the marker do this kind of wrong placement.

来源：https://stackoverflow.com/questions/31545003/gmap-net-marker-at-incorrect-position-but-when-the-map-is-zoomed-the-marker-goes

标签

winforms

google-maps

gmap.net