1.思维导图
2.知识点描述
（1）介绍
DataSet可以看做是一个内存中的数据库，包括表、数据行、数据列以及表与表之间 的关系。创建一个DataSet后，它就可以单独存在，不需要一直保持和数据库的连接。应用程序需要数据时，可以直接从内存中的DataSet中读取数据。
DataSet可以包含多个表，这些表构成了数据表集合DataTableCollection，其中的每个表都是一个DataTable对象，每个表又包括数据行DataRow和列DataColumn，所有的行构成数据行集合DataRowCollection，所有的列构成数据列集合DataColumnCollection。DataSet还可以包含表与表之间的关系DataRelation。DataRelation表示数据集中DataTable之间的关系。可以用来保证执行完整性约束、数据级联。
（2）创建DataSet对象：
DataSet dataset=new DataSet();
（3）通过DataAdapter对象存储数据
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();sqlDataAdapter.SelectCommand = sqlCommand;DataSet dataSet = new DataSet();sqlConnection.Open();sqlDataAdapter.Fill(dataSet);sqlConnection.Close();
3.应用举例
树形图（使用treeview控件分级并显示数据）
（1）连接数据库
SqlConnection sqlConnection = new SqlConnection(); ?????sqlConnection.ConnectionString = ???????????"Server=(local);Database=DB_Equipment;Integrated Security=sspi"; ????????SqlCommand sqlCommand = new SqlCommand(); ????????sqlCommand.Connection = sqlConnection; ????????sqlCommand.CommandText= ???????????????"SELECT * FROM tb_classifyone;" ???????????????+ "SELECT * FROM tb_classifytwo;" ???????????????+ "SELECT * FROM tb_classifythree;";
（2）声明并实例化数据集，用于保存查得的多张表
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(); ???????????sqlDataAdapter.SelectCommand = sqlCommand; ???????????DataSet dataSet = new DataSet(); ???????????sqlConnection.Open(); ???????????sqlDataAdapter.Fill(dataSet); ???????????sqlConnection.Close(); ???????????DataTable classifyoneTable = dataSet.Tables[0]; ???????????DataTable classifytwoTable = dataSet.Tables[1]; ???????????DataTable classifythreeTable = dataSet.Tables[2];
（3）设置分级关系（节点）
DataRelation[] dataRelations = ???????????{ ???????????????new DataRelation ????????????????????("classifyone_classifytwo" ???????????????????, classifyoneTable.Columns["No"] ???????????????????, classifytwoTable.Columns["ClassifyoneNo"] ???????????????????, false) ???????????????, new DataRelation ???????????????????("classifytwo_classifythree" ???????????????????, classifytwoTable.Columns["No"] ???????????????????, classifythreeTable.Columns["ClassifytwoNo"] ???????????????????, false) ???????????}; ???????????dataSet.Relations.AddRange(dataRelations); ???????????foreach (DataRow classifyoneRow in classifyoneTable.Rows) ???????????{ ???????????????TreeNode classifyoneNode = new TreeNode(); ???????????????classifyoneNode.Text = classifyoneRow["Name"].ToString(); ???????????????classifyoneNode.Tag = classifyoneRow["No"]; ???????????????this.trv_classify.Nodes.Add(classifyoneNode); ???????????????foreach (DataRow classifytwoRow in classifyoneRow.GetChildRows("classifyone_classifytwo")) ???????????????{ ???????????????????TreeNode classifytwoNode = new TreeNode(); ???????????????????classifytwoNode.Text = classifytwoRow["Name"].ToString(); ???????????????????classifytwoNode.Tag = classifytwoRow["No"]; ???????????????????classifyoneNode.Nodes.Add(classifytwoNode); ???????????????????foreach (DataRow classifythreeRow in classifytwoRow.GetChildRows("classifytwo_classifythree")) ???????????????????{ ???????????????????????TreeNode classifythreeNode = new TreeNode(); ???????????????????????classifythreeNode.Text = classifythreeRow["Name"].ToString(); ???????????????????????classifythreeNode.Tag = classifythreeRow["No"]; ???????????????????????classifytwoNode.Nodes.Add(classifythreeNode); ???????????????????} ???????????????} ???????????}（4）读取数据
if (this.trv_classify.SelectedNode.Level == 2) ???????????{ ???????????????int ClassifythreeNo = (int)this.trv_classify.SelectedNode.Tag; ???????????????SqlConnection sqlConnection = new SqlConnection(); ???????????????sqlConnection.ConnectionString = ???????????????????"Server=(local);Database=DB_Equipment;Integrated Security=sspi"; ???????????????SqlCommand sqlCommand = new SqlCommand(); ???????????????sqlCommand.Connection = sqlConnection; ???????????????sqlCommand.CommandText = "SELECT EquipmentNo,EquipmentName,Quantity FROM tb_inventory WHERE ClassifythreeNo=@ClassifythreeNo;"; ???????????????sqlCommand.Parameters.AddWithValue("@ClassifythreeNo", ClassifythreeNo); ???????????????SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(); ???????????????sqlDataAdapter.SelectCommand = sqlCommand; ???????????????DataTable inventoryTable = new DataTable(); ???????????????sqlConnection.Open(); ???????????????sqlDataAdapter.Fill(inventoryTable); ???????????????sqlConnection.Close(); ???????????????this.dgv_inventory.DataSource = inventoryTable; ???????????????this.dgv_inventory.Columns[this.dgv_inventory.Columns.Count - 1].AutoSizeMode = ???????????????????DataGridViewAutoSizeColumnMode.Fill; ???????????}运行结果图
ADO.Net中DataSete的应用
原文地址：https://www.cnblogs.com/JIALIH-H/p/9926145.html