ApplyExpression no longer working for me in 5.2

MapWinGIS
1

Hi,

I’ve upgraded from to 5.2 (from 5.0) and now find that “ApplyExpression” no longer works for me when using category expressions to show images for points in a shapefile.

I’m creating categories like below, where “key” is an identifier of the type of “node” the point is:

myCategory.Expression = “[Type] = “” + key + “””;

then calling:

myCategory.DrawingOptions.PointType = MapWinGIS.tkPointSymbolType.ptSymbolPicture;
myCategory.DrawingOptions.Picture = MyResource.IconImages[key];

and finally:

shp.Categories.ApplyExpression(categoryIndex);

This used to work fine and has done for a long time. However now I get no symbols, just the default point style, except for the 63rd point/node which DOES show a symbol (but the wrong one, the first one in my IconImages list as it happens, probably not coincidence). I’ve tried a couple of fields and it was the 63rd point in each case!

Also, shp.Categories.ApplyExpressions DOES work. However, I switched to the single ApplyExpression a while ago as it is much quicker for this scenario for some reason, so I’m keen to carry on using it.

Regards,

Rob H

2

Hi Rob,
You’re right, it looks as if ApplyExpression() does not work, but ApplyExpressions() does. My code used to use:

 For i = 0 To 4
     sf.Categories.ApplyExpression(i)
 Next

Now applying all styles (categories) must be done at once:
sf.Categories.ApplyExpressions()

I found no documentation of this being deprecated, and assume a bug. I reworked my code to adapt, but should have directed my concerns to the development team.

Good Luck,
David

3

Thank you @robhoney, and for the additional feedback @dgreenewalt

I looked at the history of that file, and a bug was indeed introduced in December of 2019 that prevents individual Categories being processed. I’ll try to submit a change that will be in the next build.

Regards,
Jerry.

4

Thank you both @dgreenewalt and @jerryfaust . It will be great to have a fix for this.

Regards,

Rob

5

Jira Issue MWGIS-236 has been created and a fix submitted accordingly.

1 Like
6

This issue has been fixed in MapWinGIS v5.3

I’m closing this topic.