MyGeneration学习笔记(8) ：dOOdad提供的数据绑定、特殊函数和事务处理

同上篇，主要是参考dOOdad文档，并加入了一些自己的理解。

1. 数据绑定：
(1) 绑定到DataGrid(WebApp)


if(emps.LoadAll())




...{


dvEmps = emps.DefaultView;


dgEmps.DataSource = dvEmps;


dgEmps.DataBind();


}

(2) 绑定到ComboBox(WinApp)


//get data


emps.Query.AddResultColumn(Employees.ColumnNames.EmployeeID);


emps.Query.AddResultColumn(Employees.ColumnNames.LastName);


emps.Query.AddOrderBy(Employees.ColumnNames.LastName,


WhereParameter.Dir.ASC);


emps.Query.Load();


//bind to combobox


cmbEmployees.DisplayMember = Employees.ColumnNames.LastName;


cmbEmployees.ValueMember = Employees.ColumnNames.EmployeeID;


cmbEmployees.Datasource = emps.DefaultView;

(3) 绑定到DropDownList(WebApp)


//get data


emps.Query.AddResultColumn(Employees.ColumnNames.EmployeeID);


emps.Query.AddResultColumn(Employees.ColumnNames.LastName);


emps.Query.AddOrderBy(Employees.ColumnNames.LastName,


WhereParameter.Dir.ASC);


emps.Query.Load();


//bind to drop-down list


ddlEmployees.Datasource = emps.DefaultView;


ddlEmployees.DataTextField = Employees.ColumnNames.LastName;


ddlEmployees.DataValueField = Employees.ColumnNames.EmployeeID;


ddlEmployees.Databind();

2. 特殊函数：执行自定义存储过程和SQL语句

Examples:
（1）LoadFromSql: (从数据库中检索并返回检索结果集,查询结果保存到DataTable中)


ListDictionary Parms = new ListDictionary();


Parms.Add("@parameterName1", value1);


Parms.Add("@parameterName2", value2);


parms.Add……


if(this.LoadFromSql("proc_GetSpecialEmployee", Parms))




...{


...


}



（2）LoadFromSqlNoExec: (执行无结果集的存储过程，返回受影响的行数)
int NbrOfChecks = this.LoadFromSqlNoExec("proc_CalculatePayroll");
例如：删除一条记录，dOOdad提供的文档中的方法是：先LoadByPrimaryKey,再MarkAsDeleted,最后再Save进数据库；这个过程要对数据库进行两次操作。实际上，我们可以只操作一次数据库(直接用dOOdads模板生成的存储过程)，而不用先Load。
ListDictionary Parms = new ListDictionary();
Parms.Add("@ID", empID);
int effectLine = this.LoadFromSqlNoExec("proc_EmployeeDelete",Parms);

（3）LoadFromSqlReader:(返回SqlDataReader)
SqlDataReader rdr = this.LoadFromSqlReader("proc_GetSpecialEmployee", Parms) as SqlDataReader;

（4）LoadFromSqlScalar:(返回单个值)
DateTime EarliestHireDate;
ListDictionary Parms = new ListDictionary();
Parms.Add("@Active", 1);
EarliestHireDate = Convert.ToDateTime(this.LoadFromSqlScalar("GetEarliestHireDate",Parms));

（5）LoadFromRawSql:
this.LoadFromRawSql("SELECT MIN(EM_HireDate) FROM tEmployees WHERE EM_Active = {0}","1");

3. 事务处理:


TransactionMgr tx = TransactionMgr.ThreadTransactionMgr();


try




...{


Employees emps = new Employees();


emps.AddNew();


emps.FirstName = "Jimmy";


emps.LastName = "Doe";


Products prds = new Products();


prds.AddNew();


prds.ProductName = " Lunch Box ";


prds.Discontinued = false;


tx.BeginTransaction();


emps.Save();


prds.Save();


tx.CommitTransaction();


}


catch(Exception ex)




...{


tx.RollbackTransaction();


TransactionMgr.ThreadTransactionMgrReset();


}