private void MenuItem_Click(object sender, RoutedEventArgs e)//菜单点击事件
        {
            MenuItem mn=sender as MenuItem;
            string openExcelFilename="";
            string connectionString = "";
            switch(mn.Header.ToString())//比较选取的菜单标题
            {
                case "Excel97-2003文件"://如果是"Excel97-2003文件"
                    OpenFileDialog fileOpenExcel03 = new OpenFileDialog();\\执行打开文件对话框
                    fileOpenExcel03.Filter = "Excel文件97-2003(*.xls)|*.xls";
                    if (fileOpenExcel03.ShowDialog() != true)
                        return;

                    openExcelFilename = fileOpenExcel03.FileName.Trim();
                    dbFilenameExcel = fileOpenExcel03.SafeFileName;
                    connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+openExcelFilename + ";Extended Properties='Excel 8.0'";\\根据打开的文件生成连接字符串

                    break;
                case "Excel2007-10文件"://如果是"Excel2007-10文件"
                    OpenFileDialog fileOpenExcel07 = new OpenFileDialog();\\执行打开文件对话框
                    fileOpenExcel07.Filter = "Excel2007-10文件(*.xlsx)|*.xlsx";
                    if (fileOpenExcel07.ShowDialog() != true)
                        return;

                    openExcelFilename = fileOpenExcel07.FileName.Trim();
                    dbFilenameExcel = fileOpenExcel07.SafeFileName;
                    connectionString =@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source="+openExcelFilename + ";Extended Properties='Excel 12.0'";\\根据打开的文件生成连接字符串

                    break;
               }
            OleDbConnection ODCExcel = new OleDbConnection(connectionString);//创建连接
            SelectWindow selectWin = new SelectWindow();//构造了一个新窗体
            List<string> tableNames = GetTableNames(ODCExcel);//这句话用来获取Excel文件的表名
            if (tableNames.Count <= 0)
                return;
            selectWin.cmbTableList.Items.Clear();//清空新窗体上名为cmbTableList的ComboBox的内容
            selectWin.cmbTableList.ItemsSource = tableNames;//把获取的表名加入到ComboBox中
            if (selectWin.ShowDialog() != true)
                return;
            tableNameExcel = "[" + selectWin.cmbTableList.Text + "]";

            DataSet dsExcel=new DataSet();
            string selectString = "select * From " + tableNameExcel;
            OleDbDataAdapter ODCAExcel = new OleDbDataAdapter(selectString, ODCExcel);
            try
            {
                ODCAExcel.Fill(dsExcel, "tableOpening");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);

            }
        }

        private List<string> GetTableNames(System.Data.Common.DbConnection dbConnection)
        {
            List<string> tableNames = new List<string>();
            try
            {
                dbConnection.Open();
                System.Data.DataTable schema = dbConnection.GetSchema("Tables");
                foreach (System.Data.DataRow r in schema.Rows)
                {
                    tableNames.Add((string)r["Table_Name"]);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                dbConnection.Close();
            }
            return tableNames;
        }