C# 非同步讀取資料庫裡面的資料與綁定UI的解決辦法

非同步讀取資料庫,在資料繫結的時候會出現點問題,就是表單介面會無法關閉,要結束任務才能結束進程。例如下面代碼

首先按習慣的方法，設定線程更新UI

a2.CheckForIllegalCrossThreadCalls = false;   //a2為表單名稱

下面的代碼就是從資料庫裡取得資料並綁定

private void button1_Click(object sender, EventArgs e)
        {
            SqlConnection con;
            SqlCommand com;
            try
            {
                con = new SqlConnection("UID=sa;Password=123;Initial Catalog=AD;Data Source=192.168.1.1;Asynchronous Processing=true");
                con.Open();
                com = new SqlCommand("select top 100 * from tb_user", con);
                com.BeginExecuteReader(new AsyncCallback(delDataBin), com);
            }
            catch (Exception ex)
            {
                MessageBox.Show("程式發生錯誤,資訊: " + ex.Message);
            }

        }

        private void delDataBin(IAsyncResult ar)
        {
            if (ar.IsCompleted)
            {
                SqlCommand com = (SqlCommand)ar.AsyncState;
                SqlDataReader dr = com.EndExecuteReader(ar);
                DataTable dt = new DataTable();
                dt.Load(dr);
                dr.Close();

                this.dataGridView1.DataSource = dt;   //綁定資料            

            }
        }

到這裡完成的綁定的工作，運行查看一下效果，其實這樣是會出現表單假死的現象。

下面通過Invoke 來實現

首先聲明委託  public delegate void updateDG(DataTable dt);

然後通過dataBin來綁定DataGridView

        public void dataBin(DataTable dt)
        {
            dataGridView1.DataSource = dt;
            return;
        } 

線上程裡面調用下面方法

//綁定資料
                if (this.InvokeRequired)
                {
                    updateDG ur = new updateDG(dataBin);
                    this.Invoke(ur, dt);
                }

完整的代碼如下:

 

        private void button1_Click(object sender, EventArgs e)
        {
            SqlConnection con;
            SqlCommand com;
            try
            {
                con = new SqlConnection("UID=sa;Password=123;Initial Catalog=AD;Data Source=192.168.1.1;Asynchronous Processing=true");
                con.Open();
                com = new SqlCommand("select top 100 * from tb_user", con);
                com.BeginExecuteReader(new AsyncCallback(delDataBin), com);
            }
            catch (Exception ex)
            {
                MessageBox.Show("程式發生錯誤,資訊: " + ex.Message);
            }

        }

        private void delDataBin(IAsyncResult ar)
        {
            if (ar.IsCompleted)
            {
                SqlCommand com = (SqlCommand)ar.AsyncState;
                SqlDataReader dr = com.EndExecuteReader(ar);
                DataTable dt = new DataTable();
                dt.Load(dr);
                dr.Close();

                //this.dataGridView1.DataSource = dt;//綁定資料

                if (this.InvokeRequired)
                {
                    updateDG ur = new updateDG(dataBin);
                    this.Invoke(ur, dt);
                }
            }
        }
       
        public delegate void updateDG(DataTable dt);

        public void dataBin(DataTable dt)
        {
            dataGridView1.DataSource = dt;
            return;
        }           

查運行查看一下，你就會發現結果了