参数如何在DataAdapter中初始化 [英] parameters how will be initialize in DataAdapter

问题描述

在这些代码参数中将如何初始化?

In these code parameters how will be initializing?

con = new SqlConnection(
  "Data Source=mysource;Initial Catalog=mydbname;uid=sa");
//create sql adapter for the "emp" table

SqlDataAdapter sqlDa = new SqlDataAdapter("select * from emp", con);
//create dataset instance

DataSet    dSet = new DataSet();
//fill the dataset

sqlDa.Fill(dSet, "emp");
//bind the data grid with the data set

dataGrid1.DataSource=dSet.Tables["emp"];

//build select command

SqlCommand selCmd = new SqlCommand("select * from emp",con);
sqlDa.SelectCommand=selCmd;

//build insert command

SqlCommand insCmd = new SqlCommand(
  "insert into emp (Name, Age) values(@Name, @Age)",con);
insCmd.Parameters.Add("@Name", SqlDbType.NChar, 10, "Name");  //such as here
insCmd.Parameters.Add("@Age", SqlDbType.Int, 4, "Age");
sqlDa.InsertCommand = insCmd;

//build update command

SqlCommand upCmd = new SqlCommand(
  "update emp set Name=@Name, Age=@Age where No=@No",con);
upCmd.Parameters.Add("@Name", SqlDbType.NChar, 10, "Name");
upCmd.Parameters.Add("@Age", SqlDbType.Int, 4, "Age");
upCmd.Parameters.Add("@No", SqlDbType.Int, 4, "No");
sqlDa.UpdateCommand = upCmd;

//build delete command

SqlCommand delCmd = new SqlCommand(
  "delete from emp where No=@No",con);
delCmd.Parameters.Add("@No", SqlDbType.Int, 4, "No");
sqlDa.DeleteCommand = delCmd;

//now update the data adapter with dataset.

sqlDa.Update(dSet,"emp");

推荐答案

为什么要更新dSet，以及如何处理?

最初获取到dSet并显示在DataGridView中的数据没有做任何事情.那为什么要尝试更新?

再一次，只要您愿意进行搜索，该信息就可以在Internet上免费获得.

Why are you updating dSet, and what with?

You haven''t done anything with the data you fetched into dSet initially and displayed in your DataGridView. So why try to update?

Once again, this information is freely available on the internet if only you would be prepared to search for it.

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