Question

用Google搜索，我似乎无法找到任何引用如何将sql select查询加载到keyvaluepair列表的地方。

 {
Keyvaluepair<int, name> D =new keyvaluepair <Int, name>

Using (db2connection conn =new db2connection())
 {
   Db2command cms =new db2command();

String select=    ( @"Select distinct Value, Descrip
      From cool", conn)
   Using(db2reader read =new db2reader())
  {

    }
 }

}

如何在执行查询后将值和Descrip加载到keyvaluepair列表中。 Keyvaluepair

Answer 1

您还没有提到您用于执行查询的技术，因此我假设您使用的是不会自动映射到类的基本技术。

这很容易做到。你要做的就是：

迭代您收到的每一行
使用适合列的类型创建新的KeyValuePair对象（通常为string, string或int, string）
将KeyValuePair的值设置为您从阅读器中读取的每列的值。
如果您希望稍后使用KeyValuePair执行其他操作，请尝试在迭代期间将其添加到List<KeyValuePair>

编辑好的，所以根据你的编辑，我猜你是新手。你提到你正在使用DB2。您还没有明确表示您正在使用哪个库来读取DB2，因此我将假设它是IBM提供的库。我将根据IBM的DB2DataReader class文档提供信息。

以下内容应该有效（前提是我没有打字）。我已经在评论中提供了帮助：

// this variable will have the data read from the server after all is said and done
List<KeyValuePair<int, string>>> data = new List<KeyValuePair<int, string>>();

// create the connection (replace connection string as necessary)
using (DB2Connection conn = new DB2Connection("database connection string"))
{
    // specify the query, create and open the command object 
    string qry = "Select distinct Value, Descrip from cool";
    DB2Command cmd = new DB2Command(qry, conn);
    conn.Open();

    // calling ExecuteReader() sends the query to the database and starts 
    // the process of reading the data
    using(DB2DataReader read = cmd.ExecuteReader())
    {
        // you have to call Read() for every row. It will return false if there 
        // are no more rows left
        while(read.Read())
        {
            // calling the various Get methods is how you get the data out of the reader
            // note that you pass in the index of the column for each call
            int intVal = read.GetInt32(0);
            string strVal = read.GetString(1);

            // now you're ready to create your KeyValuePair object
            KeyValuePair<int, string> tmp = new KeyVauePair<int, string>(intVal, strVal);

            // And add it to the list we defined at the start of this
            data.Add(tmp);
        }
    }
}

// and now we've got all of the data from your query wrapped up into a nice list
// called 'data'. Do with it whatever you planned

将数据从sql select加载到keyvaluepair＆lt;＆gt;

1 个答案: