Please master to see what is wrong with the code below, MapX5.0 + VC

gebihu

void drawNewFeature (
const CString&csLayerName,
double dblLng,
double dblLat,
const CString&csName,
const CString&csLevel,
const CString&csTime
)
{
CMapX * m_mapx;
CMapXStyle pStyle;

pStyle.CreateDispatch (pStyle.GetClsid ());
pStyle.SetSymbolType (miSymbolTypeVector);
pStyle.SetSymbolCharacter (34);
pStyle.SetSymbolVectorSize (16);
pStyle.SetSymbolVectorColor (miColorRed);
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CMapXLayer pLayer;
pLayer = m_mapx-> GetLayers (). Item (csLayerName);
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pLayer.BeginAccess (miAccessReadWrite);
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{
m_mapx-> SetAutoRedraw (FALSE);
pLayer.SetEditable (TRUE);
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CMapXFeature pFeature;
CMapXPoint pPoint;
CMapXFeatureFactory pFeatureFactory;

pFeatureFactory = m_mapx-> GetFeatureFactory ();
pFeature.CreateDispatch (pFeature.GetClsid ());
pPoint.CreateDispatch (pPoint.GetClsid ());
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pPoint.Set (dblLng, dblLat);
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VARIANT vtPoint;
VARIANT vtStyle;
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vtPoint.vt = VT_DISPATCH;
vtPoint.pdispVal = pPoint.m_lpDispatch;
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vtStyle.vt = VT_DISPATCH;
vtStyle.pdispVal = pStyle.m_lpDispatch;

pFeature = pFeatureFactory.CreateSymbol (vtPoint, vtStyle);
pLayer.AddFeature (pFeature.m_lpDispatch);

pLayer.Refresh ();

pLayer.SetKeyField ("name");
pFeature.SetKeyValue (csName);
// wrong here
pFeature.Update ();

pLayer.SetKeyField ("level");
pFeature.SetKeyValue (csLevel);
pFeature.Update ();

pLayer.SetKeyField ("time");
pFeature.SetKeyValue (csTime);
pFeature.Update ();

m_mapx-> ZoomTo (1000, pFeature.GetCenterX (), pFeature.GetCenterY ());
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m_mapx-> SetAutoRedraw (TRUE);
pLayer.SetEditable (FALSE);
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m_mapx-> Refresh ();
}

pLayer.EndAccess ();
}

cainan0618

What error is reported?
Put pLayer.AddFeature(pFeature.m_lpDispatch);

pLayer.Refresh();

pLayer.SetKeyField("name");
Move to
pFeature.Update();　Try it later

gebihu

First fix an error:
pLayer.AddFeature(pFeature.m_lpDispatch);
change into:
pFeature = pLayer.AddFeature(pFeature.m_lpDispatch);

I use it in a thread, and I don't know why the problem occurs. The problem is this. Sometimes you can execute this function successfully dozens of times and then there will be problems. Sometimes an error will be reported the first time. The error content is: 0xC0000005: Access Violation.
What I am wondering now is that I have not checked where there are pointers wrong.
Please help.

edcijn

It is best to have a small source code that can cause problems, easy to debug, and the problem is intuitive, and it is best to bring data (80% of the problems are caused by data) such a complex code, it is a waste of time to read line by line, not another The head of the compiler

gebihu

Thank you upstairs, but I don't think I need to put all the code and data up, because my problem has been clearly described.

43471486

It seems that you can't add graphic element information like this, you can only add a single attribute with KeyField.
To add multiple properties seems to use CMapXDataset. The landlord look for it, I am not sure about the specifics!

饭抄蛋

There seems to be a problem in the thread processing

jy666666

Mapx does not seem to support multi-threading. Did you use Mapx for the main thread? If you use it, it may be the problem.

guobiao101

stand by

gebihu

First of all, I want to thank everyone for your attention to this issue.
Through your tips, I basically know my problem.
It seems to be MapX's question about multithreading.
I want to first consider43471486's suggestions, and then listen to the饭抄蛋andjy666666() suggestions and fix the thread if it doesn't work. I think it should work in the timer of the main thread.
Thank you all, and I hope you will continue to give suggestions.