Opa! olha eu ai novamente =D, tentando passar algo de (INUTIL) UTIL pra vocês.

Hoje vou mostrar como converter uma List para DataSet, é Super Simples, vamos lá:


public static class ListConvertor
 {
 public static DataSet ConvertToDataSet<T>(IList list)
 {
 DataSet dataSet = new DataSet();

 CreateDataSet(dataSet, typeof(T), false);
 FillDataSet(typeof(T), list, dataSet, -1);
 CreateRelations(dataSet, typeof(T), null);

 return dataSet;
 }

 ///
 /// Create the structure for all the tables in the data set
 ///
 /// Data set in which tables will be created
 /// Type of which dataset has to be created
 /// Whether current type is a child table
 private static void CreateDataSet(DataSet dataSet, Type type, bool isChildTable)
 {
 DataTable dataTable = new DataTable(type.Name);

 //Create the ID columns for having relation in the tables
 dataTable.Columns.Add(new DataColumn("ID2", typeof(int)));
 if (isChildTable)
 {
 dataTable.Columns.Add(new DataColumn("ParentID2", typeof(int)));
 }

 // Create the structure for the data tables to be
 // added in the the data set
 foreach (PropertyInfo pInfo in type.GetProperties())
 {
 if (pInfo.PropertyType.IsGenericType &&
 (pInfo.PropertyType.GetGenericTypeDefinition() == typeof(List<>)
 || pInfo.PropertyType.GetGenericTypeDefinition() == typeof(IList<>)))
 {
 // If associate lists are there make then another table
 CreateDataSet(dataSet,pInfo.PropertyType.GetGenericArguments()[0],true);
 }
 else
 {
 dataTable.Columns.Add(new DataColumn(pInfo.Name, pInfo.PropertyType));
 }
 }

 //Add the table to the dataset
 dataSet.Tables.Add(dataTable);
 }

 ///
 /// Fill all the tables of data set with data in the respective list
 ///
 /// Type of which datatable is to be filled
 /// List of data
 /// Data Set in which data tables will be filled with data
 /// ID of parent record. If -1 one then no parent
 private static void FillDataSet(Type type, IList list, DataSet dataSet, int parentID)
 {
 PropertyInfo[] propertyInfos = type.GetProperties();
 DataTable dataTable = dataSet.Tables[type.Name];
 int id = dataTable.Rows.Count + 1;

 foreach (object item in list)
 {
 DataRow row = dataTable.NewRow();

 // Set new id and related parent id
 row["ID"] = id;
 if (parentID != -1)
 row["ParentID"] = parentID;

 // Load all the data from the properties of the type
 // and save them into the datatable
 foreach (PropertyInfo info in propertyInfos)
 {
 if (info.PropertyType.IsGenericType &&
 (info.PropertyType.GetGenericTypeDefinition() == typeof(List<>)
 || info.PropertyType.GetGenericTypeDefinition() == typeof(IList<>)))
 {
 IList subList = (IList)info.GetValue(item, null);
 if (subList != null && subList.Count > 0)
 {
 FillDataSet(subList[0].GetType(),
 subList,
 dataSet, id);
 }
 }
 else
 {
 row[info.Name] = info.GetValue(item, null);
 }
 }

 dataTable.Rows.Add(row);
 id++;
 }
 }

 ///
 /// Creates the relation between the tables according to the
 /// type and parent table on field ID and ParentID
 ///
 /// Data set containing parent and child table
 /// Type of the list
 /// Parent table to which relations has to be done
 private static void CreateRelations(DataSet dataSet, Type type, DataTable parentTable)
 {
 DataTable dataTable = dataSet.Tables[type.Name];

 // If parent table exsits then create relation
 // with child table on field Parent ID
 if (parentTable != null)
 {
 dataSet.Relations.Add(
 new DataRelation(parentTable.TableName + "_ID_"
 + "PARENTID_" + dataTable.TableName,
 parentTable.Columns["ID"],
 dataTable.Columns["ParentID"]));
 }

 // Check for other lists under current object
 // go for another relation if exists
 foreach (PropertyInfo pInfo in type.GetProperties())
 {
 if (pInfo.PropertyType.IsGenericType &&
 (pInfo.PropertyType.GetGenericTypeDefinition() == typeof(List<>)
 || pInfo.PropertyType.GetGenericTypeDefinition() == typeof(IList<>)))
 {
 // If associate lists are there make then another table
 CreateRelations(dataSet,pInfo.PropertyType.GetGenericArguments()[0],dataTable);
 }
 }
 }
 }

Vamos para as explicações:


ArrayList sequence = new ArrayList();
 IList list = (IList)sequence;
 DataSet ds = ListConvertor.ConvertToDataSet<LancamentosDetalhado>(list);

Como nos queremos passar uma List para DataSet, vamos forçar um ArrayList ser uma lista, já que ele extend de IList, estamos fazendo isso com o cast (IList), logo após aplicamos o metodo STATIC, ListConvertor.ConvertToDataSet<LancamentosDetalhado>(list);,

pois a assinatura do metodo esta como static, logo só pode ser chamado a partir da classe.

Simples assim.

Nenhum post foi relacionado a este

Imprimir Post Imprimir Post