public class DataSetHelper { private class FieldInfo { public string RelationName; public string FieldName; public string FieldAlias; public string Aggregate; } private DataSet ds; private ArrayList m_FieldInfo; private string m_FieldList; private ArrayList GroupByFieldInfo; private string GroupByFieldList; public DataSet DataSet { get { return ds; } } #region Construction public DataSetHelper() { ds = null; } public DataSetHelper(ref DataSet dataSet) { ds = dataSet; } #endregion #region Private Methods private bool ColumnEqual(object objectA, object objectB) { if (objectA == DBNull.Value && objectB == DBNull.Value) { return true; } if (objectA == DBNull.Value || objectB == DBNull.Value) { return false; } return (objectA.Equals(objectB)); } private bool RowEqual(DataRow rowA, DataRow rowB, DataColumnCollection columns) { bool result = true; for (int i = 0; i < columns.Count; i++) { result &= ColumnEqual(rowA[columns[i].ColumnName], rowB[columns[i].ColumnName]); } return result; } private void ParseFieldList(string fieldList, bool allowRelation) { if (m_FieldList == fieldList) { return; } m_FieldInfo = new ArrayList(); m_FieldList = fieldList; FieldInfo Field; string[] FieldParts; string[] Fields = fieldList.Split(','); for (int i = 0; i <= Fields.Length - 1; i++) { Field = new FieldInfo(); FieldParts = Fields[i].Trim().Split(' '); switch (FieldParts.Length) { case 1: //to be set at the end of the loop break; case 2: Field.FieldAlias = FieldParts[1]; break; default: return; } FieldParts = FieldParts[0].Split('.'); switch (FieldParts.Length) { case 1: Field.FieldName = FieldParts[0]; break; case 2: if (allowRelation == false) { return; } Field.RelationName = FieldParts[0].Trim(); Field.FieldName = FieldParts[1].Trim(); break; default: return; } if (Field.FieldAlias == null) { Field.FieldAlias = Field.FieldName; } m_FieldInfo.Add(Field); } } private DataTable CreateTable(string tableName, DataTable sourceTable, string fieldList) { DataTable dt; if (fieldList.Trim() == "") { dt = sourceTable.Clone(); dt.TableName = tableName; } else { dt = new DataTable(tableName); ParseFieldList(fieldList, false); DataColumn dc; foreach (FieldInfo Field in m_FieldInfo) { dc = sourceTable.Columns[Field.FieldName]; DataColumn column = new DataColumn(); column.ColumnName = Field.FieldAlias; column.DataType = dc.DataType; column.MaxLength = dc.MaxLength; column.Expression = dc.Expression; dt.Columns.Add(column); } } if (ds != null) { ds.Tables.Add(dt); } return dt; } private void InsertInto(DataTable destTable, DataTable sourceTable, string fieldList, string rowFilter, string sort) { ParseFieldList(fieldList, false); DataRow[] rows = sourceTable.Select(rowFilter, sort); DataRow destRow; foreach (DataRow sourceRow in rows) { destRow = destTable.NewRow(); if (fieldList == "") { foreach (DataColumn dc in destRow.Table.Columns) { if (dc.Expression == "") { destRow[dc] = sourceRow[dc.ColumnName]; } } } else { foreach (FieldInfo field in m_FieldInfo) { destRow[field.FieldAlias] = sourceRow[field.FieldName]; } } destTable.Rows.Add(destRow); } } private void ParseGroupByFieldList(string FieldList) { if (GroupByFieldList == FieldList) { return; } GroupByFieldInfo = new ArrayList(); FieldInfo Field; string[] FieldParts; string[] Fields = FieldList.Split(','); for (int i = 0; i <= Fields.Length - 1; i++) { Field = new FieldInfo(); FieldParts = Fields[i].Trim().Split(' '); switch (FieldParts.Length) { case 1: //to be set at the end of the loop break; case 2: Field.FieldAlias = FieldParts[1]; break; default: return; } FieldParts = FieldParts[0].Split('('); switch (FieldParts.Length) { case 1: Field.FieldName = FieldParts[0]; break; case 2: Field.Aggregate = FieldParts[0].Trim().ToLower(); Field.FieldName = FieldParts[1].Trim(' ', ')'); break; default: return; } if (Field.FieldAlias == null) { if (Field.Aggregate == null) { Field.FieldAlias = Field.FieldName; } else { Field.FieldAlias = Field.Aggregate + "of" + Field.FieldName; } } GroupByFieldInfo.Add(Field); } GroupByFieldList = FieldList; } private DataTable CreateGroupByTable(string tableName, DataTable sourceTable, string fieldList) { if (fieldList == null || fieldList.Length == 0) { return sourceTable.Clone(); } else { DataTable dt = new DataTable(tableName); ParseGroupByFieldList(fieldList); foreach (FieldInfo Field in GroupByFieldInfo) { DataColumn dc = sourceTable.Columns[Field.FieldName]; if (Field.Aggregate == null) { dt.Columns.Add(Field.FieldAlias, dc.DataType, dc.Expression); } else { dt.Columns.Add(Field.FieldAlias, dc.DataType); } } if (ds != null) { ds.Tables.Add(dt); } return dt; } } private void InsertGroupByInto(DataTable destTable, DataTable sourceTable, string fieldList, string rowFilter, string groupBy) { if (fieldList == null || fieldList.Length == 0) { return; } ParseGroupByFieldList(fieldList); ParseFieldList(groupBy, false); DataRow[] rows = sourceTable.Select(rowFilter, groupBy); DataRow lastSourceRow = null, destRow = null; bool sameRow; int rowCount = 0; foreach (DataRow sourceRow in rows) { sameRow = false; if (lastSourceRow != null) { sameRow = true; foreach (FieldInfo Field in m_FieldInfo) { if (!ColumnEqual(lastSourceRow[Field.FieldName], sourceRow[Field.FieldName])) { sameRow = false; break; } } if (!sameRow) { destTable.Rows.Add(destRow); } } if (!sameRow) { destRow = destTable.NewRow(); rowCount = 0; } rowCount += 1; foreach (FieldInfo field in GroupByFieldInfo) { switch (field.Aggregate) { case null: case "": case "last": destRow[field.FieldAlias] = sourceRow[field.FieldName]; break; case "first": if (rowCount == 1) { destRow[field.FieldAlias] = sourceRow[field.FieldName]; } break; case "count": destRow[field.FieldAlias] = rowCount; break; case "sum": destRow[field.FieldAlias] = Add(destRow[field.FieldAlias], sourceRow[field.FieldName]); break; case "max": destRow[field.FieldAlias] = Max(destRow[field.FieldAlias], sourceRow[field.FieldName]); break; case "min": if (rowCount == 1) { destRow[field.FieldAlias] = sourceRow[field.FieldName]; } else { destRow[field.FieldAlias] = Min(destRow[field.FieldAlias], sourceRow[field.FieldName]); } break; } } lastSourceRow = sourceRow; } if (destRow != null) { destTable.Rows.Add(destRow); } } private object Min(object a, object b) { if ((a is DBNull) || (b is DBNull)) { return DBNull.Value; } if (((IComparable)a).CompareTo(b) == -1) { return a; } else { return b; } } private object Max(object a, object b) { if (a is DBNull) { return b; } if (b is DBNull) { return a; } if (((IComparable)a).CompareTo(b) == 1) { return a; } else { return b; } } private object Add(object a, object b) { if (a is DBNull) { return b; } if (b is DBNull) { return a; } return (Convert.ToDecimal(a) + Convert.ToDecimal(b)); } private DataTable CreateJoinTable(string tableName, DataTable sourceTable, string fieldList) { if (fieldList == null) { return sourceTable.Clone(); } else { DataTable dt = new DataTable(tableName); ParseFieldList(fieldList, true); foreach (FieldInfo field in m_FieldInfo) { if (field.RelationName == null) { DataColumn dc = sourceTable.Columns[field.FieldName]; dt.Columns.Add(dc.ColumnName, dc.DataType, dc.Expression); } else { DataColumn dc = sourceTable.ParentRelations[field.RelationName].ParentTable.Columns[field.FieldName]; dt.Columns.Add(dc.ColumnName, dc.DataType, dc.Expression); } } if (ds != null) { ds.Tables.Add(dt); } return dt; } } private void InsertJoinInto(DataTable destTable, DataTable sourceTable, string fieldList, string rowFilter, string sort) { if (fieldList == null) { return; } else { ParseFieldList(fieldList, true); DataRow[] Rows = sourceTable.Select(rowFilter, sort); foreach (DataRow SourceRow in Rows) { DataRow DestRow = destTable.NewRow(); foreach (FieldInfo Field in m_FieldInfo) { if (Field.RelationName == null) { DestRow[Field.FieldName] = SourceRow[Field.FieldName]; } else { DataRow ParentRow = SourceRow.GetParentRow(Field.RelationName); DestRow[Field.FieldName] = ParentRow[Field.FieldName]; } } destTable.Rows.Add(DestRow); } } } #endregion #region SelectDistinct / Distinct ///
/// 按照fieldName从sourceTable中选择出不重复的行， /// 相当于select distinct fieldName from sourceTable /// ///
表名 ///
源DataTable ///
列名 /// 一个新的不含重复行的DataTable，列只包括fieldName指明的列 public DataTable SelectDistinct(string tableName, DataTable sourceTable, string fieldName) { DataTable dt = new DataTable(tableName); dt.Columns.Add(fieldName, sourceTable.Columns[fieldName].DataType); object lastValue = null; foreach (DataRow dr in sourceTable.Select("", fieldName)) { if (lastValue == null || !(ColumnEqual(lastValue, dr[fieldName]))) { lastValue = dr[fieldName]; dt.Rows.Add(new object[] { lastValue }); } } if (ds != null && !ds.Tables.Contains(tableName)) { ds.Tables.Add(dt); } return dt; } ///
/// 按照fieldName从sourceTable中选择出不重复的行， /// 相当于select distinct fieldName1,fieldName2,,fieldNamen from sourceTable /// ///
表名 ///
源DataTable ///
列名数组 /// 一个新的不含重复行的DataTable，列只包括fieldNames中指明的列 public DataTable SelectDistinct(string tableName, DataTable sourceTable, string[] fieldNames) { DataTable dt = new DataTable(tableName); object[] values = new object[fieldNames.Length]; string fields = ""; for (int i = 0; i < fieldNames.Length; i++) { dt.Columns.Add(fieldNames[i], sourceTable.Columns[fieldNames[i]].DataType); fields += fieldNames[i] + ","; } fields = fields.Remove(fields.Length - 1, 1); DataRow lastRow = null; foreach (DataRow dr in sourceTable.Select("", fields)) { if (lastRow == null || !(RowEqual(lastRow, dr, dt.Columns))) { lastRow = dr; for (int i = 0; i < fieldNames.Length; i++) { values[i] = dr[fieldNames[i]]; } dt.Rows.Add(values); } } if (ds != null && !ds.Tables.Contains(tableName)) { ds.Tables.Add(dt); } return dt; } ///
/// 按照fieldName从sourceTable中选择出不重复的行， /// 并且包含sourceTable中所有的列。 /// ///
表名 ///
源表 ///
字段 /// 一个新的不含重复行的DataTable public DataTable Distinct(string tableName, DataTable sourceTable, string fieldName) { DataTable dt = sourceTable.Clone(); dt.TableName = tableName; object lastValue = null; foreach (DataRow dr in sourceTable.Select("", fieldName)) { if (lastValue == null || !(ColumnEqual(lastValue, dr[fieldName]))) { lastValue = dr[fieldName]; dt.Rows.Add(dr.ItemArray); } } if (ds != null && !ds.Tables.Contains(tableName)) { ds.Tables.Add(dt); } return dt; } ///
/// 按照fieldNames从sourceTable中选择出不重复的行， /// 并且包含sourceTable中所有的列。 /// ///
表名 ///
源表 ///
字段 /// 一个新的不含重复行的DataTable public DataTable Distinct(string tableName, DataTable sourceTable, string[] fieldNames) { DataTable dt = sourceTable.Clone(); dt.TableName = tableName; string fields = ""; for (int i = 0; i < fieldNames.Length; i++) { fields += fieldNames[i] + ","; } fields = fields.Remove(fields.Length - 1, 1); DataRow lastRow = null; foreach (DataRow dr in sourceTable.Select("", fields)) { if (lastRow == null || !(RowEqual(lastRow, dr, dt.Columns))) { lastRow = dr; dt.Rows.Add(dr.ItemArray); } } if (ds != null && !ds.Tables.Contains(tableName)) { ds.Tables.Add(dt); } return dt; } #endregion #region Select Table Into ///
/// 按sort排序，按rowFilter过滤sourceTable， /// 复制fieldList中指明的字段的数据到新DataTable，并返回之 /// ///
表名 ///
源表 ///
字段列表 ///
过滤条件 ///
排序 /// 新DataTable public DataTable SelectInto(string tableName, DataTable sourceTable, string fieldList, string rowFilter, string sort) { DataTable dt = CreateTable(tableName, sourceTable, fieldList); InsertInto(dt, sourceTable, fieldList, rowFilter, sort); return dt; } #endregion #region Group By Table public DataTable SelectGroupByInto(string tableName, DataTable sourceTable, string fieldList, string rowFilter, string groupBy) { DataTable dt = CreateGroupByTable(tableName, sourceTable, fieldList); InsertGroupByInto(dt, sourceTable, fieldList, rowFilter, groupBy); return dt; } #endregion #region Join Tables public DataTable SelectJoinInto(string tableName, DataTable sourceTable, string fieldList, string rowFilter, string sort) { DataTable dt = CreateJoinTable(tableName, sourceTable, fieldList); InsertJoinInto(dt, sourceTable, fieldList, rowFilter, sort); return dt; } #endregion #region Create Table public DataTable CreateTable(string tableName, string fieldList) { DataTable dt = new DataTable(tableName); DataColumn dc; string[] Fields = fieldList.Split(','); string[] FieldsParts; string Expression; foreach (string Field in Fields) { FieldsParts = Field.Trim().Split(" ".ToCharArray(), 3); // allow for spaces in the expression // add fieldname and datatype if (FieldsParts.Length == 2) { dc = dt.Columns.Add(FieldsParts[0].Trim(), Type.GetType("System." + FieldsParts[1].Trim(), true, true)); dc.AllowDBNull = true; } else if (FieldsParts.Length == 3) // add fieldname, datatype, and expression { Expression = FieldsParts[2].Trim(); if (Expression.ToUpper() == "REQUIRED") { dc = dt.Columns.Add(FieldsParts[0].Trim(), Type.GetType("System." + FieldsParts[1].Trim(), true, true)); dc.AllowDBNull = false; } else { dc = dt.Columns.Add(FieldsParts[0].Trim(), Type.GetType("System." + FieldsParts[1].Trim(), true, true), Expression); } } else { return null; } } if (ds != null) { ds.Tables.Add(dt); } return dt; } public DataTable CreateTable(string tableName, string fieldList, string keyFieldList) { DataTable dt = CreateTable(tableName, fieldList); string[] KeyFields = keyFieldList.Split(','); if (KeyFields.Length > 0) { DataColumn[] KeyFieldColumns = new DataColumn[KeyFields.Length]; int i; for (i = 1; i == KeyFields.Length - 1; ++i) { KeyFieldColumns[i] = dt.Columns[KeyFields[i].Trim()]; } dt.PrimaryKey = KeyFieldColumns; } return dt; } #endregion }