在为现有要素类新增字段时，有可能会爆出该表正被其他程序或其他人使用，这时我们就会添加失败，解决办法如下：
在新增字段之前，先修改SchemaLock的状态
ISchemaLock pSchemaLock = m_pOriginFeatureClass as ISchemaLock;
pSchemaLock.ChangeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);
然后再新增字段
//Add New Field
int nIndexOfGBTYPE = m_pOriginFeatureClass.Fields.FindField("GB_TYPE");
if (nIndexOfGBTYPE == -1)
{
IField pField = new FieldClass();
IFieldEdit pFieldEdit = pField as IFieldEdit;
pFieldEdit.Name_2 = "GB_TYPE";
pFieldEdit.Type_2 = esriFieldType.esriFieldTypeString;
pFieldEdit.IsNullable_2 = true;
pFieldEdit.AliasName_2 = "GB_TYPE";
pFieldEdit.DefaultValue_2 = "";
pFieldEdit.Editable_2 = true;
pFieldEdit.Length_2 = 100;
m_pOriginFeatureClass.AddField(pField);
}
//最后进行恢复处理
pSchemaLock.ChangeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);