Modifying an existing feature

Editing existing features is performed by retrieving a row from a table, editing the row, then calling FeatureDataTable.SaveInFeatureSource(), FeatureSource.SaveEdits() or if you are using a FeatureDataReader you can call the Update method. When updating an existing feature, make a selection to determine the feature you want to update. The selection can be obtained by defining a QueryFilter, which may contain a spatial and attribute query component, then passing this as a parameter to the FeatureSource.GetDataTable method to obtain a FeatureDataTable for the selection or call FeatureSource.GetDataReader() to get back a DataReader. The SelectionMapAction can assist you by providing a graphic selection and returning a collection of FeatureDataTables. Using ADO calls, you can update the appropriate rows or access the geometry you wwant to update.

The following example shows how to change a value of selected features:

// Selects a specific cache layer 
FeatureSource featureSource = mobileCache1.FeatureSource["parcels"] as FeatureSources; 

// Checks if attributes are editable 
if (!featureSource.AllowModify) 
  return; 

// Query filter specifing feature IDs 
QueryFilter queryFilter = new QueryFilter(new int[] { 5473, 14004, 13997, 7404, 8556, 10490, 16117 });

// Sets the initial parcel number 
int apn = 100000000; 

// Gets the position of the column to be edited 
int apnFieldIndex = featureSource.Columns.IndexOf("APN"); 

// Using a feature datareader to update features 
using (FeatureDataReader featureDataReader = featureSource.GetDataReader(queryFilter, null)) 
  {
  while(featureDataReader.Read()) 
    { 
      // Gets the feature ID 
      int fid = featureDataReader.GetFid(); 

      // Sets the parcel number
      featureDataReader.SetString(apnFieldIndex, apn.ToString()); 

      //Increments the parcel number 
      apn += 1; 

      // Prints info
      System.Diagnostics.Debug.WriteLine("FID: " + fid + ", APN: " + featureDataReader.GetValue(apnFieldIndex));

      // Updates the feature layer data table 
      featureDataReader.Update(); 
    }
  }