条码打印异步调用

       做了将近一年的进销存软件产品，今天无意中发现了一个对象

BackgroundWorker

 后台线程处理，觉得挺管用，所以做了一个很小的Demo（条码打印），界面给人一种很真实的感觉，好，切入正题，

所以我们来看看效果图：

 好，相信现在大家都已经看到了这种效果图了，好，我们看看代码的实现：

首先： 我们搭建一个业务逻辑层，类名为：ParamUtil

我们看看代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace Action
{
    public class ParamUtil
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="cmd"></param>
        public ParamUtil(string cmd)
        {
              
        }

        /// <summary>
        ///  构造函数
        /// </summary>
        /// <param name="cmd"></param>
        public ParamUtil()
        {
            
        }

        /// <summary>
        /// 初始化数据
        /// </summary>
        public DataTable CBind1()
        {
            DataTable dt = new DataTable();

            dt.Columns.Add("a",typeof(string));
            dt.Columns.Add("b",typeof(string));
            dt.Columns.Add("c",typeof(string));

            //造数据
            for (int i = 0; i < 100;++i )
            {
                DataRow dr = dt.NewRow();
                dr["a"] = "颜色";
                dr["b"] = "尺码";
                dr["c"] = "未打印";
                dt.Rows.Add(dr);
            }

            return dt;
        }
    }

}

好，现在我们的业务逻辑层已经搭建好，我们来看客户端的实现：

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 Action;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        #region 设计说明
        #endregion

        #region 变动记录
        //Ver 1.0.0.1 (2010-11-29) Andy20101987 初始化数据
        #endregion

        #region 变量

        /// <summary>
        /// 后台线程
        /// </summary>
        private BackgroundWorker bgw;

        /// <summary>
        /// 设置datagridview第一行的索引值
        /// </summary>
        /// <param name="rowindex"></param>
        private delegate void ChangeDGVFirstDisplayedScrolling(int rowindex);

        #endregion

        #region 框架方法
        /// <summary>
        /// 窗体加载事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_Load(object sender, EventArgs e)
        {
            // 实例化
            Action.ParamUtil paramutil = new ParamUtil();

            DataTable dt = new DataTable();
            dt =paramutil.CBind1();

            this.bindingSource1.DataMember = dt.TableName;
            this.bindingSource1.DataSource = dt;

            this.toolStripProgressBar1.Maximum = bindingSource1.Count;
        }

        #endregion

        #region 成员方法

        /// <summary>
        /// 打印
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnPrint_Click(object sender, EventArgs e)
        {
            this.toolStripStatusLabel1.Text = "正在打印...";

            bgw = new BackgroundWorker();
            bgw.WorkerReportsProgress = true;
            bgw.WorkerSupportsCancellation = true;
            bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
            bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
            bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);

            bgw.RunWorkerAsync();
        }

        #endregion

        #region 事件

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void bgw_DoWork(object sender, DoWorkEventArgs e)
        {
            bindingSource1.MoveFirst();
            int rowPosition = bindingSource1.Position;

            while (rowPosition <= bindingSource1.Count)
            {
                if (bgw.CancellationPending)
                    break;

                this.dataGridView1.Rows[bindingSource1.Position].Selected = true;
                DataRowView currentRowView = bindingSource1.Current as DataRowView;
                currentRowView.Row["c"] = "正在打印...";

                System.Threading.Thread.Sleep(1000);
                currentRowView.Row["c"] = "打印完成！";

                this.dataGridView1.Rows[rowPosition].DefaultCellStyle.ForeColor = Color.Red;

                if (bindingSource1.Position > 6)
                {
                    bgw.ReportProgress(bindingSource1.Position - 6);
                }
                else
                {
                    bgw.ReportProgress(0);
                }

                bindingSource1.MoveNext();
                rowPosition++;
            }

            bgw.Dispose();
        }

        /// <summary>
        /// 停止
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnStop_Click(object sender, EventArgs e)
        {
            this.toolStripStatusLabel1.Text = "取消打印！";
            this.toolStripProgressBar1.Value = 0;

            bgw.CancelAsync();
            bgw.Dispose();
        }

        /// <summary>
        /// 退出
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnExit_Click(object sender, EventArgs e)
        {
            Close();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            dataGridView1.FirstDisplayedScrollingRowIndex = e.ProgressPercentage;
            dataGridView1.Refresh();

            if (this.toolStripProgressBar1.Value.Equals(bindingSource1.Count))
            {
                toolStripProgressBar1.Value = bindingSource1.Count;
            }
            else
            {
                toolStripProgressBar1.Value++;
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            this.toolStripStatusLabel1.Text = "打印完成！";
        }

        #endregion

    }
}

好，现在客户端也组建好，就可以看到我们上面的效果图了，大家感觉试一试，希望对大家有所帮助，

因为时间比较匆忙，今天就写在这，后期会对其进行更详细的述说，也会发表更多的文章，希望大家一起

来学习。