指数数组的边界之外. ? [英] Index was outside the bounds of the array. ?

问题描述

cmd = new SqlCommand("select RefferBy from UsersIncome where UserName='" + Label1.Text + "'", con);

    dtr = cmd.ExecuteReader();
        if (dtr.Read())
    {
       Label2.Text = dtr[0].ToString();
       Label3.Text = dtr[1].ToString();
        Label4.Text = dtr[2].ToString();
       Label5.Text = dtr[3].ToString();
    }

它表明Index不在数组的范围内，为什么??????

it is showing Index was outside the bounds of the array why ?????

推荐答案

因为dtr没有足够的列来支持您的代码.

Because dtr doesn''t have enough columns to support your code.

cmd = new SqlCommand("select RefferBy from UsersIncome where UserName='" + Label1.Text + "'", con);

    dtr = cmd.ExecuteReader();
        if (dtr.Read())
    {
       Label2.Text = dtr[0].ToString();
       /*Label3.Text = dtr[1].ToString();
        Label4.Text = dtr[2].ToString();
       Label5.Text = dtr[3].ToString();*/
    }

查看 SQL教程 [ ^ ]，以便对SQL语法有基本的了解.

您的代码的问题是，SELECT语句中只有1列. "RefferBy".

如果要读取所有行，则必须循环DataReader.
查看使用DataReader检索数据 [

Check out SQL Tutorial[^] for basic understanding of SQL syntax.

The problem with your code is, that there is only 1 column in your SELECT statement. "RefferBy".

If you want to read all rows, you have to loop the DataReader.
Check out Retrieving Data Using a DataReader[^]

Hope it can help you.

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