C# 异步读取数据库里面的数据与绑定UI的解决办法
異步讀取數據庫,在數據綁定的時候會出現點問題,就是窗體界面會無法關閉,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為窗體名稱
下面的代碼就是從數據庫里取得數據并綁定
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("程序發生錯誤,信息: " + 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;?? //綁定數據????????????
??????????? }
??????? }
到這里完成的綁定的工作，運行查看一下效果，其實這樣是會出現窗體假死的現象。
下面通過Invoke 來實現
首先聲明委托? public delegate void updateDG(DataTable dt);
然后通過dataBin來綁定DataGridView
??????? public void dataBin(DataTable dt)
??????? {
??????????? dataGridView1.DataSource = dt;
??????????? return;
??????? }?
在線程里面調用下面方法
//綁定數據
??????????????? 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("程序發生錯誤,信息: " + 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;//綁定數據
????????????????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
轉載于:https://www.cnblogs.com/whtydn/archive/2009/07/07/1518209.html
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