topic Re: how to add a field ,then set value in ArcObjects SDK Questions

how to add a field ,then set value

yanli — Thu, 10 Oct 2013 13:47:51 GMT


//*****Add a Field
 IField2 pField = new Field() as IField2;
                IFieldEdit2 pFieldEdit = pField as IFieldEdit2;
                pFieldEdit.Name_2 = "BldCoding2";
                pFieldEdit.AliasName_2 = "BldCoding2";
                //pFieldEdit.Length_2 = 3;
                pFieldEdit.Type_2 = esriFieldType.esriFieldTypeString;
                pFieldEdit.DefaultValue_2 = "1";
                fcBiuding.AddField(pField);

//*****Then get the index of field

IEnumFeature pEnumFeature = ConstDef.m_Editor.EditSelection;
 IFeature pBuildingFeature = null;
                IFeatureCursor pFeaCur = null;
while ((pBuildingFeature = pEnumFeature.Next()) != null)
{
   int i = pBuildingFeature.Fields.FindField("BldCoding2");//  here  is Error ,i=-1

}

why I can't get the index of Field???

Re: how to add a field ,then set value

AlexanderGray — Thu, 10 Oct 2013 13:55:49 GMT

This is from the IFieldsEdit.AddField help section:
"AddField is used when creating a fields collection and cannot be used to insert a field into a fields collection belonging to an existing table. To add a field to an existing object class, use the IClass::AddField method."

Re: how to add a field ,then set value

JohnStephens — Sun, 12 Dec 2021 01:20:50 GMT

You might want to make sure that a schema lock isn't preventing you from adding the field:

public void AddFieldToFeatureClass(IFeatureClass featureClass, IField field)
{
  ISchemaLock schemaLock = (ISchemaLock)featureClass;

  try
  {
    // A try block is necessary, as an exclusive lock may not be available.
    schemaLock.ChangeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);

    // Add the field.
    featureClass.AddField(field);
  }
  catch (Exception exc)
  {
    // Handle this in a way appropriate to your application.
    Console.WriteLine(exc.Message);
  }
  finally
  {
    // Set the lock to shared, whether or not an error occurred.
    schemaLock.ChangeSchemaLock(esriSchemaLock.esriSharedSchemaLock);
  }
}

Re: how to add a field ,then set value

DuncanHornby — Thu, 10 Oct 2013 14:03:34 GMT

Not sure why its failing, may be some schema not refreshing? Anyway I would suggest after your line

fcBiuding.AddField(pField);

get the index position then using something like this (this is VB)

i = fcBiuding.FindField("BldCoding2")

and use that in your subsequent code.

Re: how to add a field ,then set value

NeilClemmons — Thu, 10 Oct 2013 14:34:44 GMT

Since you're getting the feature you want to edit from the editor's feature selection I'm assuming you're running this code inside of an edit session. If so, you shouldn't be adding/deleting fields during an edit session. Add the field before you start editing.