访问DataReader中的特定行

本文关键字：DataReader 访问 | 更新日期: 2023-09-27 18:04:18

我有一个数据阅读器显示一个列表的游戏周在js轮询器

我需要能够添加一个if语句来改变当前gameweek的div类。

这是我当前的代码:

if (dReader.HasRows) {
    while (dReader.Read()) {                
        gameweekList.Text += "<div class='"item'"><h4>Gameweek " + 
            (dReader["gameweekID"].ToString()) + "</h4></div>";
    }
} else {
    gameweekList.Text = "Error Finding Gameweeks";
}
dReader.Close();
conn.Close();

实际上我想添加if(dreader[1])，然后添加额外的位，这是怎么可能的?

访问DataReader中的特定行

我发现使用DataTable或DataSet更容易。像这样:

DataTable dt = new DataTable();
dt.Load(dreader)

那么您可以更容易地使用DataTable访问某一行。行属性。

…

if (dReader.HasRows) {
    while (dReader.Read()) {
        if ( dReader["gameweekID"].ToString() == currentWeekId ) 
        {    
            gameweekList.Text += "<div class='"somethingSpecial'"><h4>Gameweek " + 
            (dReader["gameweekID"].ToString()) + "</h4></div>";
        } 
        else 
        {
            gameweekList.Text += "<div class='"item'"><h4>Gameweek " + 
            (dReader["gameweekID"].ToString()) + "</h4></div>";
        }
    }
} else {
    gameweekList.Text = "Error Finding Gameweeks";
}
dReader.Close();
conn.Close();

如果我没记错的话，你可以像这样计算读者的阅读次数。然后，当计数适合您时，您可以添加一些不同的内容:

int count = 0;
if (dReader.HasRows) {
    while (dReader.Read()) {
        if(count == 1)  //add special row              
            gameweekList.Text += "something special " + dReader["gameweekID"].ToString();          
        else
            gameweekList.Text += "<div class='"item'"><h4>Gameweek " + 
            (dReader["gameweekID"].ToString()) + "</h4></div>";
        count++;
    }
} else {
    gameweekList.Text = "Error Finding Gameweeks";
}
dReader.Close();
conn.Close();

但是如果你想同时读取当前和后续，你应该先读取一次，然后开始像这样循环读取:

if (dReader.HasRows) {
    string previousRead = string.Empty;
    dReader.Read();
    previousRead = dReader["gameweekID"].ToString();
    while (dReader.Read()) {
          //use current and previous read 
          //dReader["gameweekID"].ToString()
          //previousRead
          //update previousRead for the next read
          previousRead = dReader["gameweekID"].ToString();
    }
} else {
    gameweekList.Text = "Error Finding Gameweeks";
}
dReader.Close();
conn.Close();

要获得第一行，从0开始并始终将其放入数据表中，因为直接从数据阅读器读取总是会遇到问题;

if (dReader.HasRows) {
DataTable dt = new DataTable();
dt.Load(dreader)
gameweekList.Text = dt.Rows[0]["gameweekID"]
}
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