对现有FeatureClass添加字段的问题

IFeatureClass pFc= ((IFeatureLayer)lyrRec).FeatureClass;           

IFieldsEdit fldsE = pFc.Fields as IFieldsEdit;
IField fld = new FieldClass();
IFieldEdit2 fldE = fld as IFieldEdit2;
fldE.Type_2 = esriFieldType.esriFieldTypeString;
fldE.Name_2 = "XXX";
ic.AddField(fld);

int idTest = gpsFc.Fields.FindField("XXX");

调试跟踪，发现IdTest不等于-1 说明执行成功，但是再次启动发现字段未成功添加到要素集


查看帮助 ，对已存在的要素集添加字段 需要用到IClass

IFeatureClass pFc= ((IFeatureLayer)lyrRec).FeatureClass;  
IClass pClass=pFc as IClass;         


IFieldsEdit fldsE = pFc.Fields as IFieldsEdit;
IField fld = new FieldClass();
IFieldEdit2 fldE = fld as IFieldEdit2;
fldE.Type_2 = esriFieldType.esriFieldTypeString;
fldE.Name_2 = "XXX";
pClass.AddField(fld);

再次执行 成功！


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.


意思就是说如果修改的是当前已经存在的表或者要数类的字段，那么你就使用IClass::AddField方法生成字段
 
 
新建要素集则不会出现这种情况