[GIS] (arcengine) export selected features from sde to shapefile (with joined fields)

arcgis-enginearcobjects

I have a SDE featureclass that is joined to an access table in my map control. I want to export selected features of the SDE layer to a shapefile AND retain the joined fields.
this following method works great (except for retaining the joined fields)

public void ExportMapLyrToShapefile(ESRI.ArcGIS.Carto.ILayer pInLayer, string inputName, string outputPath, string qry)
    {
        // Set the GeoFeatureLayer to the layer in the map so that we can use it as the input feature later
        IGeoFeatureLayer pInGFLayer = (IGeoFeatureLayer)pInLayer;
        IFeatureLayer pInFeatureLayer = (IFeatureLayer)pInGFLayer;
        IFeatureClass inputFeatureClass = pInFeatureLayer.FeatureClass;
        IDataset inputDataset = (IDataset)inputFeatureClass;
        IDatasetName inputDatasetName = (IDatasetName)inputDataset.FullName;

        // Get the layer's selection set (the selected/highlighted features of the layer in the mapcontrol)
        IFeatureSelection featureSelection = (IFeatureSelection)pInFeatureLayer;
        ISelectionSet selectionSet = featureSelection.SelectionSet;

        // Create a feature class name for the output shapefile and open the output's workspace
        IWorkspaceFactory shpWorkspaceFactory = new ShapefileWorkspaceFactoryClass();
        IWorkspace shpWorkspace = shpWorkspaceFactory.OpenFromFile(outputPath, 0);
        IDataset shpWorkspaceDataset = (IDataset)shpWorkspace;
        IWorkspaceName workspaceName = (IWorkspaceName)shpWorkspaceDataset.FullName;
        IFeatureClassName shpFeatureClassName = new FeatureClassNameClass();
        IDatasetName shpDatasetName = (IDatasetName)shpFeatureClassName;
        shpDatasetName.WorkspaceName = workspaceName;
        shpDatasetName.Name = qry.Replace(" = ", "");

        // Use the IFieldChecker interface to make sure all of the field names are valid for the output shapefile.
        IFieldChecker fieldChecker = new FieldCheckerClass();
        IFields shapefileFields = null;
        IEnumFieldError enumFieldError = null;
        fieldChecker.InputWorkspace = inputDataset.Workspace;
        fieldChecker.ValidateWorkspace = shpWorkspace;
        fieldChecker.Validate(inputFeatureClass.Fields, out enumFieldError, out shapefileFields);

        // We also need to retrieve the GeometryDef from the input feature class.
        int shapeFieldPosition = inputFeatureClass.FindField(inputFeatureClass.ShapeFieldName);
        IFields inputFields = inputFeatureClass.Fields;
        IField shapeField = inputFields.get_Field(shapeFieldPosition);
        IGeometryDef geometryDef = shapeField.GeometryDef;

        // Now we create a feature data converter to "Export" the selected features to a shapefile
        IFeatureDataConverter2 featureDataConverter2 = new FeatureDataConverterClass();
        IEnumInvalidObject enumInvalidObject = featureDataConverter2.ConvertFeatureClass(inputDatasetName, null, selectionSet, null, shpFeatureClassName, geometryDef, shapefileFields, "", 1000, 0);
    }

the issue is with the IFieldChecker interface. it validates all the fields and removed the joined fields before exporting to a shapefile.

Does anyone have any insight on this issue? If so, please help! I'm stumpped!

btw… i also tried using an IDisplayTable as my input feature and I get the same output (missing joined fields)

Thanks,
Derek

Best Answer

I'm not familiar with IFieldChecker, but I typically use the code below to export a joined featureclass to a shapefile and it works fine for me (does use IDisplayTable).

 private void Export2Shapefile(IFeatureLayer pBlockLayer)
    {
        IDisplayTable pBlkTbl = pBlockLayer as IDisplayTable;
        IFeatureClass pBlkClass = pBlkTbl.DisplayTable as IFeatureClass;

        IDataset pDataset = pBlkClass as IDataset;
        IDatasetName pInDSname = pDataset.FullName as IDatasetName;
        IWorkspaceFactory pOutWSFact = new ShapefileWorkspaceFactoryClass();
        IWorkspace pOutWS = pOutWSFact.OpenFromFile(ScratchPath, 0);

        IDataset pDData = pOutWS as IDataset;
        IWorkspaceName pWSname = pDData.FullName as IWorkspaceName;
        IDatasetName pOutDSname = new FeatureClassNameClass();
        pOutDSname.Name = "gridshape";
        pOutDSname.WorkspaceName = pWSname;

        IExportOperation pExpOp = new ExportOperationClass();
        pExpOp.ExportFeatureClass(pInDSname, null, null, null, pOutDSname as IFeatureClassName, 0);

    }

Related Solutions

ArcObjects – Exporting Selected Features to a New Shapefile

You are using the IExportOperation interface, it allows you to specify the query filter when exporting data so that you do not need to deal with cursors yourself.

You can modify your code by first creating the query filter:

var queryFilter = new QueryFilterClass();
queryFilter.SubFields = "*";
queryFilter.WhereClause = "NOT TestDone=0";

Then adding the query filter as a parameter to your export function and using it in your IExportOperation.ExportFeatureClass call:

public void ExportFeatureClass(string strLayerName, IFeatureClass pFeatureClass, IWorkspace pOutWorkspace, ISpatialReference pSpatialReference, IGeometryDef pGeometryDef, IQueryFilter pQueryFilter)
{
    ...
    pExportOperation.ExportFeatureClass((IDatasetName)pInFeatureClassName, pQueryFilter, null, pGeometryDef, pOutFeatureClassName, 0);
    ...
}

[GIS] Geometry from multiple selected features into one geometry

You can use ITopologicalOperator.ConstructUnion.

The steps would be as follows:

Create an instance of the Polygon class and cast that to ITopologicalOperator. This polygon instance will contain the result.
Since ITopologicalOperator.ConstructUnion takes an IEnumGeometry to specify the geometries to union (or in your words, concatenate), create an instance of GeometryBag class, which implements IEnumGeometry.
Cast the geometry bag to IGeometryCollection so that you can add your source polygons to it.
Pass your geometry bag to the ITopologicalOperator.ConstructUnion method on the polygon created in step 1.

As far as enumerating the selection is concerned, your method of retrieving list of IDs and getting the row for every single ID is VERY inefficient. Performance is much better if you just use IFeatureSelection.SelectionSet.Search() method. You would specify a null query filter argument when calling this method since you want all the features in the selection. The result will be a cursor which you can enumerate.

Best Answer

Related Solutions

ArcObjects – Exporting Selected Features to a New Shapefile

[GIS] Geometry from multiple selected features into one geometry

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