索引超出了阵列自动售货机的范围 [英] Index was outside the bounds of the array vending machine

问题描述

因此，我正在对自动售货机进行编程，并且查询的是用于从自动售货机中选择产品的按钮，感谢您的帮助.价格，产品和产品编号都是数据库的一部分.

 私有  void  runQurey(字符串查询)
       {
           OleDbCommand cmd = 新 OleDbCommand(query，conn);
           OleDbDataReader cusReader = cmd.ExecuteReader();

           lblprice.Text = " ;
           lblquantity.Text = " ;

           同时(cusReader.Read())
           {
               lblprice.Text = cusReader.GetValue( 0 ).ToString();
               lblquantity.Text = cusReader.GetValue( 1 ).ToString();
           }
       }

       私有 无效 btnselect1_Click(对象发​​件人，EventArgs e)
       {
           runQurey(" )；

       }

解决方案

好吧...您正在从数据库中请求一列:

 runQurey(" )； 

然后尝试处理两列:

 lblprice.Text = cusReader.GetValue( 0 ).ToString();
lblquantity.Text = cusReader.GetValue( 1 ).ToString(); 

我怀疑您想返回更多列，因此请尝试执行以下操作:

 runQurey(" private void runQurey(String query)
       {
           OleDbCommand cmd = new OleDbCommand(query, conn);
           OleDbDataReader cusReader = cmd.ExecuteReader();

           lblprice.Text = "";
           lblquantity.Text = "";

           while (cusReader.Read())
           {
               lblprice.Text = cusReader.GetValue(0).ToString();
               lblquantity.Text = cusReader.GetValue(1).ToString();
           }
       }

       private void btnselect1_Click(object sender, EventArgs e)
       {
           runQurey("SELECT Price FROM Products WHERE ProductID = 1");

       }

解决方案

Well...you are requesting one column from your DB:

runQurey("SELECT Price FROM Products WHERE ProductID = 1");

And then trying to process two columns:

lblprice.Text = cusReader.GetValue(0).ToString();
lblquantity.Text = cusReader.GetValue(1).ToString();

I suspect you want to return more columns, so try something like:

runQurey("SELECT Price, Quantity FROM Products WHERE ProductID = 1");

your query is not correct,bcoz u didn''t take quantity value from ur table but u r bindinding quantity value from reader .Ur datareader is holding only price alone not quantity value

Your query is not right.Add 2 columns name if you want two value in select query.

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