/// <summary>
        /// 查询所有表信息
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnViewDbInfo_Click(object sender, EventArgs e)
        {
            btnViewDbInfo.Enabled = false;
            Dictionary <string, string> tables;

            tables = (cbDbType.SelectedIndex == 0)?UtilSqlserver.TableList():UtilMysql.TableList();
            string tablenames = "";

            this.listResult.Clear();
            foreach (string tablename in tables.Values)
            {
                tablenames += tablename + "\r\n";
            }
            this.listResult.AppendText(tablenames);
            Console.WriteLine(tablenames);
            btnViewDbInfo.Enabled = true;
        }
        /// <summary>
        /// 点选表列表框选择默认从数据库读一次所有表
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void cbTables_MouseClick(object sender, MouseEventArgs e)
        {
            //if (cbTables.Items.Count <= 0)
            //{
            cbTables.Items.Clear();
            Dictionary <string, string> tables;

            tables = (cbDbType.SelectedIndex == 0) ? UtilSqlserver.TableList() : UtilMysql.TableList();
            foreach (string cur_tablename in tables.Values)
            {
                this.cbTables.Items.Add(cur_tablename);
            }
            //this.cbTables.SelectedIndex = 0;

            btnColumns.Enabled = true;
            //}
        }
        /// <summary>
        /// 查看指定表列名,如果没有指定表,默认指定第一张表
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnColumns_Click(object sender, EventArgs e)
        {
            btnColumns.Enabled = false;
            this.listResult.Clear();
            string tablename;

            if (cbTables.Items.Count <= 0)
            {
                Dictionary <string, string> tables;
                tables    = (cbDbType.SelectedIndex == 0) ? UtilSqlserver.TableList() : UtilMysql.TableList();
                tablename = tables.Values.First();
                foreach (string cur_tablename in tables.Values)
                {
                    this.cbTables.Items.Add(cur_tablename);
                }
                this.cbTables.SelectedIndex = 0;
            }
            else
            {
                tablename = (string)cbTables.SelectedItem;
            }
            Dictionary <string, Dictionary <string, string> > columnInfos;

            columnInfos = (cbDbType.SelectedIndex == 0) ? UtilSqlserver.FieldInfoList(tablename) : UtilMysql.FieldInfoList(tablename);

            this.listResult.AppendText("显示指定表的信息:" + tablename + "\r\n");
            string columnResult, comment;

            foreach (Dictionary <string, string> columnInfo in columnInfos.Values)
            {
                comment = "";
                if (columnInfo.ContainsKey("Comment"))
                {
                    comment = columnInfo["Comment"];
                    string[] commentArr = comment.Split(new char[2] {
                        '\r', '\n'
                    });
                    comment = commentArr[0];
                    comment = "|备注:" + comment;
                }
                columnResult = "列名:" + columnInfo["Field"] + comment + "|类型:" + columnInfo["Type"] + "|是否允许为空:" + columnInfo["Null"] + "\r\n";
                this.listResult.AppendText(columnResult);
            }

            btnColumns.Enabled = true;
        }