第七周学习笔记

ADO.Net中DataTable的应用

• 知识点描述

ADO.NET可以在与数据库断开连接的方式下通过DataTable对象进行数据处理，当需要更新数据时才重新与数据源进行连接，并更新数据源。DataTable对象表示保存在本机内存中的表，它提供了对表中行列数据对象的各种操作。同时还可以进行相对应的增删改查的相对应的操作

基本属性有五种：

1. Columns  表示列的集合
2. Constraints    特定DataTable的约束集合
3. DataSet    所属的数据集
4. PrimaryKey   主键
5. Rows    表示行的集合
6. TableName

 

接下来是常用的构造函数方法

一种是ADO.NET DataTable构造函数方法，创建DataTable对象的实例，以表名字符串作为参数；

另外一种为创建DataTable对象的实例，无参数。创建后，再修改TableName属性，给表设定表名。

基本方法在思维导图中都有呈现出来。

 

• 代码和示例

运行结果：

 

代码：

            SqlConnection sqlConnection = new SqlConnection();                                          

            sqlConnection.ConnectionString =

                "Server=(local);Database=YiMiao;Integrated Security=sspi";                          

            SqlCommand sqlCommand = new SqlCommand();                                                   

            sqlCommand.Connection = sqlConnection;                                                        

            sqlCommand.CommandText = "SELECT * FROM tb_YiMiao;";                                      

            SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();                                          

            sqlDataAdapter.SelectCommand = sqlCommand;                                                    

            sqlDataAdapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;                           

            this.YiMiaoTable = new DataTable();                                                         

            sqlConnection.Open();                                                                          

            sqlDataAdapter.Fill(this.YiMiaoTable);                                                        

            sqlConnection.Close();                                                                  

                                                           

            this.YiMiaoByName = new DataView();                                                        

            this.YiMiaoByName.Table = this.YiMiaoTable;                                              

            this.YiMiaoByName.Sort = "YMName ASC";                                                      

            this.dgv_YiMiao.Columns.Clear();                                                               

            this.dgv_YiMiao.DataSource = this.YiMiaoTable;                                                  

            this.dgv_YiMiao.Columns["ID"].HeaderText = "编号";                                             

            this.dgv_YiMiao.Columns["YMName"].HeaderText = "疫苗名称";

            this.dgv_YiMiao.Columns["producecom"].HeaderText = "生产公司";

            this.dgv_YiMiao.Columns["category"].HeaderText = "类型";

            this.dgv_YiMiao.Columns["Money"].HeaderText = "价格";

            this.dgv_YiMiao.Columns["Beizhu"].Visible = false;                                             

 

• 思维导图