选择组合框时出现此错误“索引0为负数或高于行数。” [英] Got this error while selecting a combobox "Index 0 is either negative or above rows count."

问题描述

private void comboPrtn_SelectionChangeCommitted(object sender, EventArgs e)
       {




           ////---------------------------Show price-------------------

               SqlDataAdapter ddamtp = new SqlDataAdapter("select * from assign_price('" + this.comboPrtn.SelectedValue + "')", con);
               DataSet ddsamtp = new DataSet();
               ddamtp.Fill(ddsamtp, "price");
               DataView vddamtp = new DataView(ddsamtp.Tables["price"]);
               txtUprice.Text = vddamtp[0]["PRICE"].ToString();

           ////----------------------------end-------------------------
       }

推荐答案

自，据我所知 0 不是负数，并且它不能高于行数，这样的消息是完全错误的。

- Carlo The NitPick



但是你的代码也错了（索引相等行数）：

Since, as far as I know 0 is not negative, and it can't be either above the rows count, such message is plain wrong.
--Carlo The NitPick

However your code is wrong too (the index is equal to row count):

txtUprice.Text = vddamtp[0]["PRICE"].ToString();

您正在访问 vddamtp [0] 而不确定此类数据视图是否包含至少一行。

You are accessing vddamtp[0] without being sure such dataview contains, at least, one row.

假设 assign_price 是您创建的函数，您需要确保它返回一些值。如果没有，那么行：

Assuming assign_price is a function you created, you need to be sure it returns some values. If it doesn't, then the the line:

txtUprice.Text = vddamtp[0]["PRICE"].ToString();

将给出您引用的异常。

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