技术，高手帮忙，在位置0处没有任何行？

Question

没有任何错误跟警告，可是运行的时候，添加功能时候，就会显示“在位置0处没有任何行”，麻烦高手帮下忙，详细点哈~~菜鸟的我
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using JXCCManage.ClassInfo;
using JXCCManage.GoodMenhod;
using System.Data.SqlClient;namespace JXCCManage
{
    public partial class frmSellGoods : Form
    {
        string js = "";
        public string kcId = "";
        public string GoodId = null;
        tb_SellGoods sellGoods = null;
        DataTable dt = null;
        tb_SellGoodsMenthod SellMedthor = null;
        AutoSetId aid = null;
        tb_KcGoodsMenthod KcMedthor = null;
        public static int intFalg;
        public frmSellGoods(string js)
        {
            InitializeComponent();
            sellGoods = new tb_SellGoods();
            SellMedthor = new tb_SellGoodsMenthod();
            aid = new AutoSetId();
            this.js = js;
            KcMedthor = new tb_KcGoodsMenthod();
            this.ActiveControl = txtGoodsName;
            this.KeyPreview = true;
        }        /// <summary>
        /// 获取进货量
        /// </summary>
        /// <returns></returns>
        //private int GetSpLiang()
        //{
        //    int num;
        //    DataTable dt = new DataTable();
        //    dt = KcMedthor.KcGoodsInfoFind(GoodId,1);
        //    num =Convert.ToInt32(dt.Rows[0][4].ToString());
        //    return num;
        //}        /// <summary>
        /// 获取库存量
        /// </summary>
        /// <returns></returns>
        private int GetKcLiang()
        {
            int KcNum;
            DataTable dt = new DataTable();
            dt = KcMedthor.KcGoodsInfoFind(GoodId, 1);
            KcNum = Convert.ToInt32(dt.Rows[0][5].ToString());
            return KcNum;
        }        /// <summary>
        /// 更新库存数量
        /// </summary>
        private void UpdateKcLiang()
        {
            int OrginKcLiang, CurrentKcLiang;
            OrginKcLiang = GetKcLiang();
            int SellNum = Convert.ToInt32(txtSellNum.Text);
            try
            {
                if (SellNum < OrginKcLiang)
                {
                    if (SellMedthor.SellGoodsInfoInert(sellGoods) == 1)
                    {
                        MessageBox.Show("添加成功！");
                        intFalg = 0;
                        FillDataGrid();
                        ClearControl();
                        ControlStatus();
                    }
                    else
                    {
                        MessageBox.Show("添加失败！");
                        ControlStatus();
                        intFalg = 0;
                    }
                    CurrentKcLiang = OrginKcLiang - SellNum;
                    int i = KcMedthor.KcGoodsInfoUpdate(GoodId, CurrentKcLiang);
                    if (i > 0)
                    {
                        MessageBox.Show("库存事实更新成功！");
                    }
                }
                else
                {
                    MessageBox.Show(SellNum.ToString() + ">库存数量！", "提示");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }        }
        //用回车完成Tab的功能，使用onkeypress

Answer 1

http://www.google.com.hk/search?hl=zh-CN&source=hp&biw=788&bih=475&q=%E5%9C%A8%E4%BD%8D%E7%BD%AE0%E5%A4%84%E6%B2%A1%E6%9C%89%E4%BB%BB%E4%BD%95%E8%A1%8C&aq=f&aqi=&aql=&oq=

Answer 2

DataTable的使用原则一般是“先判断后使用”，除非你保证dt.ROWS.count一定大于零。
dt = KcMedthor.KcGoodsInfoFind(GoodId, 1);
  KcNum = Convert.ToInt32(dt.Rows[0][5].ToString());
像这样的代码如果dt行数为零，就会出现显示“在位置0处没有任何行”，这样的错误。

Answer 3

dt = KcMedthor.KcGoodsInfoFind(GoodId, 1);
if(dt.Rows.Count>0){
  KcNum = Convert.ToInt32(dt.Rows[0][5].ToString());
}
  return KcNum;
判断下

Answer 4

修改后的。
if (dt != null && dt.Rows.Count > 0)
 /// <summary>
    /// 获取库存量
    /// </summary>
    /// <returns></returns>
    private int GetKcLiang()
    {
        int KcNum;
        DataTable dt = new DataTable();
        dt = KcMedthor.KcGoodsInfoFind(GoodId, 1);
        if (dt != null && dt.Rows.Count > 0)
        {
            KcNum = Convert.ToInt32(dt.Rows[0][5].ToString());
        }
        return KcNum;
    }