Inserting Features and Rows

Recently I was inserting features in a feature class but my code was rather slow so I looked around for another method and the following is what I found.

First you need to start an edit session and then you can use the code below. This is just a short body of code to give you an idea on how to use the different objects.

IFeatureCursor insertFeatCursor = outputFeatClass.Insert(true);

foreach (object featureToInsert in featuresToInsert)
{
    IFeatureBuffer outputFeatBuffer = outputFeatClass.CreateFeatureBuffer();
    // set the shape
    outputFeatBuffer.Shape = ...
    // set the different values
    outputFeatBuffer.set_Value(fieldIndex, value);
    // insert the feature buffer
    insertFeatCursor.InsertFeature(outputFeatBuffer);
}
insertFeatCursor.Flush();

If you now save and close your edit session the features are inserted. The code for inserting rows in a table is very similar.

ITable table;
ICursor insertCursor = table.Insert(true);
IRowBuffer rowBuffer = table.CreateRowBuffer();
rowBuffer.set_Value(fieldIndex, value);
insertCursor.InsertRow(rowBuffer);
insertCursor.Flush();

If you have any comments or questions, let me know !!!

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Using foreach with the ICursor
Drag Drop from ArcCatalog
Pythonnet (call .NET from Python)

Drag Drop from ArcCatalog

As you probably already noticed you can drag drop items within ArcGIS. For example you can drag a feature class from ArcCatalog to ArcMap or from ArcMap or ArcCatalog to a geoprocessing form. In this post I'm going to show you what has to be done to enable drag drop behavior from ArcCatalog and Windows Explorer to a textbox.

To enable drag drop on a textbox I added event handlers for DragEnter, DragOver and DragDrop for my textbox called textBoxPath. In the DragEnter and DragOver handlers I check whether the dragged object is valid. If this is the case the drag drop effect is set to All. This is a combination of the Copy, Move, and Scroll effect. But its in the DragDrop event handler and more precisely in the helper function GetPaths that the most import stuff happens. As you can see the Data property of the DragEventArgs is processed by the GetPaths method and if any paths to feature classes or tables are found the first path is shown. After that I added a small hack to put the cursor at the end of the text in the textbox.

private void TextBoxPath_DragEnter(object sender, DragEventArgs e)
{
 e.Effect = EsriDragDrop.IsValid(e.Data) ? DragDropEffects.All : DragDropEffects.None;
}

private void TextBoxPath_DragOver(object sender, DragEventArgs e)
{
 e.Effect = EsriDragDrop.IsValid(e.Data) ? DragDropEffects.All : DragDropEffects.None;
}

private void TextBoxPath_DragDrop(object sender, DragEventArgs e)
{
 List<string> paths = EsriDragDrop.GetPaths(e.Data);
 TextBox txtBoxPath = (TextBox)sender;
 if (paths.Count > 0)
 {
  // set value of textbox to the first found path
  txtBoxPath.Text = esriDragDrop.Paths[0];
  // place cursor at the end of the textbox
  txtBoxPath.SelectionStart = txtBoxPath.TextLength;
 }
}

In the below EsriDragDrop class I placed the IsValid and GetPaths methods. The IsValid method checks whether the IDataObject coming from the drag event contains any valid objects. The GetPaths method retrieves those valid objects and returns the paths to the found feature classes and tables. It uses the IDataObjectHelper interface and its GetNames and GetFiles methods to access the objects in the IDataObject. Note that only feature classes and tables will be returned by my code but this constraint can easily be removed by not checking the Type of the datasetName. I didn't add any functionality to check whether the file path dragged from a Windows Explorer to the textbox was valid but you can implement this by using the Geoprocessor object and its Exists and Describe methods or by trying to open the table or feature class.

using System.Collections.Generic;
using System.Windows.Forms;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.SystemUI;

namespace GisSolved.DragDrop
{
 public class EsriDragDrop
 {
  const string DATAOBJECT_ESRINAMES = "ESRI Names";
  public static bool IsValid(IDataObject dataObject)
  {
   return dataObject.GetDataPresent(DATAOBJECT_ESRINAMES) ||
    dataObject.GetDataPresent(System.Windows.Forms.DataFormats.FileDrop);
  }
  public static List<string> GetPaths(IDataObject dataObject)
  {
   List<string> foundPaths = new List<string>();
   IDataObjectHelper dataObjectHelper = new DataObjectHelperClass();
   dataObjectHelper.InternalObject = (object)dataObject;
   
   if (dataObjectHelper.CanGetNames())
   {
    IEnumName enumNames = dataObjectHelper.GetNames();
    IName name;
    while ((name = enumNames.Next()) != null)
    {
     if (name is IDatasetName)
     {
      IDatasetName datasetName = (IDatasetName)name;
      // only accept feature classes and tables
      if (datasetName.Type == esriDatasetType.esriDTFeatureClass ||
       datasetName.Type == esriDatasetType.esriDTTable)
      {
       string path = System.IO.Path.Combine(datasetName.WorkspaceName.PathName, datasetName.Name);
       foundPaths.Add(path);
      }
     }
    }
   }
   else if (dataObjectHelper.CanGetFiles())
   {
    string[] paths = (string[])dataObjectHelper.GetFiles();
    foreach (string path in paths)
    {
     // TODO : Add code here to check if the file path is a valid path
     foundPaths.Add(path);
    }
   }
   return foundPaths;
  }
 }
}

This is all you need to implement drag drop behavior from ArcCatalog or Windows Explorer to your textbox. If you want to implement drag drop from ArcMap to your form I suggest you to read this and this. Any comments or suggestions ? Let me know.

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Table to csv

On the ESRI support forum someone asked how to convert an attribute table to a csv file. This can easily be done with a Python script. First we import arcgisscripting and the CursorIterator and initialize the geoprocessing object.

import arcgisscripting, string
from cursoriterator import CursorIterator

gp = arcgisscripting.create()

The next step is to initialize the different variables for this script. The workspace is the path to the directory, file geodatabase, personal geodatabase, sde,... where the script can find the table or feature class that you want to convert. The table is the name of the table or feature class you want to export. The outputpath is the path to file where you want your export to be written to. Be aware that the output directory should exist. If the file doesn't exist it will be created otherwise it will be overwritten. The csvseparator is the column separator for the output file. It could be anything you want. If you want to use tabs you should set this variable to '\t'. The last variable is ignorefields. If a field name in the table or featureclass is equal to a string in this list then this field won't be exported. This can be used for excluding the shape field, the objectid field or other fields you don't want to appear in the output file.

gp.workspace = r'' ## workspace of the table or feature class
table = '' ## table or feature class from wich the attributes should be exported
outputpath = r'' ## path to the file where the output should be written to
csvseparator = ',' ## column separator field
ignorefields = [] ##list with fields to ignore

Then we define a function wich purpose is to create a list of fieldnames that are to be exported to the output file. This is done by iterating over the fields cursor that can be accessed by the gp function listfields. The fields that are in the ignorefields list won't be returned.

def get_fieldnames(fields, ignorefields=[]):
   ignorefieldsupper = map(string.upper, ignorefields)
   fields = CursorIterator(fields)
   fields_output = []
   for field in fields:
       if not field.name.upper() in ignorefieldsupper:
           fields_output.append(field.name)
   return fields_output


fields = gp.listfields(table)
fieldnames = get_fieldnames(fields)

Now we are going to iterate over the rows in the table or featureclass and create a list with a string representation of each row. For each field we add the value of a field to a list. Then we concactenate this values with the chosen separator and add this to the output list.

rows = gp.searchcursor(table)
rows = CursorIterator(rows)

output = []
output.append(csvseparator.join(fieldnames))
for row in rows:
   outputrow = []
   for fieldname in fieldnames:
       outputrow.append(str(row.getvalue(fieldname)))

   outputrow = csvseparator.join(outputrow)
   output.append(outputrow)

Finally we write the outputlist to the defined outputpath.

f = open(outputpath, 'w')
f.write('\n'.join(output))
f.close()

The full code can be found on the arcscripts site.