从excel读入数据到交错数组

Question

从excel读入数据到交错数组，已实例化过，然后for (int i = 0; i < count[0]; i++)
            {
                p[0][i] = Convert.ToInt16(dataGridView1[0, i].Value);
                x1[0][i] = Convert.ToDouble(dataGridView1[1, i].Value);
                y1[0][i] = Convert.ToDouble(dataGridView1[2, i].Value);
                x2[0][i] = (Convert.ToDouble(dataGridView1[3, i].Value));
                y2[0][i] = (Convert.ToDouble(dataGridView1[4, i].Value));            }报错“对象不能从 DBNull 转换为其他类型”，请问各位大虾如何处理啊，谢谢谢谢

Answer 1

using System;
using System.Collections.Generic;
using System.Text;
using Excel = Microsoft.Office.Interop.Excel;
using System.Data.OleDb;
using System.Data;
using System.Windows.Forms;
namespace ExcelDivision
{
    class ExcelSearch
    {
        /// <summary>
        /// 查询类
        /// </summary>
        /// <param name="excelFile">excel文件完整路径</param>
        public ExcelSearch(string excelFile)
        {
            this.excelFile = excelFile;
            try
            {
                excelConString = string.Format("Provider=Microsoft.Jet.OLEDB.4.0; Data Source={0}; Extended Properties=Excel 8.0", excelFile);
                excelConnnection = new OleDbConnection(excelConString);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);               
            }
        }
        private  string excelFile;
        private string excelConString;
        public OleDbConnection excelConnnection;
        /// <summary>
        /// 查询全部数据
        /// </summary>
        /// <returns></returns>
        public DataTable getAllDate(string sheetName)
        {
            DataTable dt = null;
            string sql = string.Format("select * from [{0}$] ", sheetName);
            try
            {              
                DataSet ds = new DataSet();
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql,excelConnnection);
                adapter.Fill(ds);
                dt = ds.Tables[0];
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);            }
            finally
            {
                excelConnnection.Close();
            }
            return dt;
        }
        /// <summary>
        /// 获取excel中有多少列数据
        /// </summary>
        /// <param name="sheetName"></param>
        /// <returns></returns>
        public int columnCount(string sheetName)
        {
            int num = 0;
            string sql = string.Format("select * from [{0}$] ", sheetName);
            try
            {
                OleDbCommand command = new OleDbCommand(sql, excelConnnection);
                excelConnnection.Open();
                OleDbDataReader dr = command.ExecuteReader();
                dr.Read();
                num=dr.FieldCount;
                dr.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);            }
            finally
            {
                excelConnnection.Close();
            }
            return num;
        }
        
        /// <summary>
        ///按列分类查询
        /// </summary>
        /// <param name="sheetName">工作表名</param>
        /// <param name="columnName">列名</param>
        /// <param name="condition">条件</param>
        /// <returns></returns>
        public DataTable getDataForColumnAsCondition(string sheetName,string columnName, string condition)
        {
            DataTable dt = null;
            string sql = string.Format("select * from [{0}$] where {1}='{2}'",sheetName,columnName,condition);
            try
            {                
                DataSet ds = new DataSet();
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql,excelConnnection);
                adapter.Fill(ds);
                dt = ds.Tables[0];
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);            }
            finally
            {
                excelConnnection.Close();
            }
            return dt;
        }
        /// <summary>
        /// 获取某一列的值（无重复值）
        /// </summary>
        /// <param name="sheetName">工作表</param>
        /// <param name="columnName">要获取列的名字</param>
        /// <returns></returns>
        public DataTable getDataColumnName(string sheetName,string columnName)
        {
            DataTable dt = null;
            string sql = string.Format("select DISTINCT {1} from [{0}$] ", sheetName, columnName);
            try
            {
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql, excelConnnection);
                DataSet ds = new DataSet();
                adapter.Fill(ds);
                dt = ds.Tables[0];
            }
            catch (Exception)
            {
                
                
            }
            return dt;
        }        public List<string> getRow(string sheetName)
        {
            List<string> lst = null;
            return lst;
        }
        /// <summary>
        /// 获取指定单元格的文本
        /// </summary>
        /// <param name="sheetName"></param>
        /// <param name="row"></param>
        /// <param name="col"></param>
        /// <returns></returns>
        public string GetCellStr(string sheetName, int row, int col)
        {
            string str = "";
            try
            {
                //Open(xlsFileName);
                Excel.Application app = new Excel.Application();
                Excel.Workbooks wbs = app.Workbooks;
                Excel.Workbook wb = wbs.Add(excelFile);                //设置禁止弹出保存和覆盖的询问提示框
                app.DisplayAlerts = false;
                app.AlertBeforeOverwriting = false;
                app.UserControl = true;//如果只想用程序控制该excel而不想让用户操作时候，可以设置为false                Excel.Worksheet worksheet = (Excel.Worksheet)wb.Worksheets[sheetName];
                Excel.Range r = (Excel.Range)(worksheet.Cells[row, col]);
                str = r.Text.ToString();
                app.Quit();
                //Close();
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message.ToString());
            }
            return str;           
        }    }
}
这是对excel的查询代码，你看看是否有用

Answer 2

对象不能从 DBNull 转换为其他类型获取出来的数据是DBNull，先判断一下吧
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