给要素集添加字段

IFeatureClass pToFeatureClass=“要素集”；

IClass pClass = pToFeatureClass as IClass;

IField fld = new FieldClass();
IFieldEdit2 fldE = fld as IFieldEdit2;
fldE.Type_2 = tmpField.Type;
fldE.Name_2 = tmpField.Name;
fldE.AliasName_2 = tmpField.AliasName;
pClass.AddField(fld);

IFieldsEdit fldsE = pToFeatureClass.Fields as IFieldsEdit;
                for (int i = 0; i < pFromFeatureClass.Fields.FieldCount; i++)
                {
                    var tmpField = pFromFeatureClass.Fields.Field[i];
                    var index = pToFeatureClass.Fields.FindField(tmpField.Name);
                    if (tmpField.Name.Contains("FID") || tmpField.Name.Contains("Shape")) continue;
                    if (index == -1)
                    {
                        IField fld = new FieldClass();
                        IFieldEdit2 fldE = fld as IFieldEdit2;
                        fldE.Type_2 = tmpField.Type;
                        fldE.Name_2 = tmpField.Name;
                        fldE.AliasName_2 = tmpField.AliasName;
                        pClass.AddField(fld);
                    }
                }