c# Winform 多线程操作 |
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c# Winform 多线程操作
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主要是对一个过程需要的时间很长执行时会出现界面假死的情况 方法1： Application.DoEvents()，这种方法当你拖动窗体时，界面不会假死。但在你拖动时代码不再执行，也就是阻塞了，当你不再控制窗体时会继续执行，其实这还是一个单线程 for (int i = 0; i < 10000; i++) { for (int j = 0; j < 100000; j++) { textBox1.Text = i.ToString() + " " + j.ToString(); Application.DoEvents(); } }
方法2：多线程 2.1：取消控件跨线程检测（不推荐有时会出现一些莫名奇妙的错误如控件不能加载等问题） 2.1.1取消窗体内控件的跨线程检查（单个控件取消也可以） public Form1() { InitializeComponent(); CheckForIllegalCrossThreadCalls = false;//干掉检测 不再检测跨线程 }2.1.2新建线程实现跨线程访问 /// /// 新建线程并执行 /// /// /// private void button1_Click(object sender, EventArgs e) { ThreadStart thStart = new ThreadStart(Pro);//threadStart委托 Thread thread = new Thread(thStart); thread.Priority = ThreadPriority.Highest; thread.IsBackground = true; //关闭窗体继续执行 thread.Start(); } public void Pro() { for (int i = 0; i < 10000; i++) { for (int j = 0; j < 100000; j++) { textBox1.Text = j.ToString(); } } }
2.2：主线程中操作(推荐) 2.2.1 不用取消跨线程访问 /// /// 新建线程并执行 /// /// /// private void button1_Click(object sender, EventArgs e) { ThreadStart thStart = new ThreadStart(Pro);//threadStart委托 Thread thread = new Thread(thStart); thread.Priority = ThreadPriority.Highest; thread.IsBackground = true; //关闭窗体继续执行 thread.Start(); } public void Pro() { for (int i = 0; i < 10000; i++) { for (int j = 0; j < 100000; j++) { if (textBox1.InvokeRequired)//不同线程访问了 textBox1.Invoke(new Action(SetTxtValue), textBox1, j.ToString());//跨线程了 else//同线程直接赋值 textBox1.Text = j.ToString(); } } } private void SetTxtValue(TextBox txt, string value) { txt.Text = value; }注：多个线程同时访问一个方法时 需要锁定 public static readonly object obj = new object(); public void Pro() { //lock(obj){}=Monitor.Enter(obj) Monitor.Exit(obj) lock (obj) { for (int i = 0; i < 10000; i++) { for (int j = 0; j < 100000; j++) { if (textBox1.InvokeRequired)//不同线程访问了 textBox1.Invoke(new Action(SetTxtValue), textBox1, j.ToString());//跨线程了 else//同线程直接赋值 textBox1.Text = j.ToString(); } } } }
3.窗体与自定义类之间的多线程操作（适用数据量大查询速度慢时 让数据在新线程中查询 防主线程卡死） 3.1自定义类中定义事件，并定义各事件执行的步骤方法 3.2窗体中实现类，并生成类各事件，在多线程中执行自定义类的步骤方法 3.3 代码3.1  
public class WeiTuo
{
public int count { get; set; }
public event EventHandler StartEvent;
public event EventHandler MidEvent;
public event EventHandler EndEvent;
public event EventHandler EEvent;
public void ExecEvent()
{
try
{
using (SqlConnection con = new SqlConnection("server=.;uid=sa;pwd=123;database=oa"))
{
using (SqlDataAdapter adp = new SqlDataAdapter("select * from a", con))
{
DataTable dt = new DataTable();
adp.Fill(dt);
StartEvent(dt.Rows.Count, null);
for (int i = 0; i < dt.Rows.Count; i++)
{
a ai = new a() {
ID = (int)dt.Rows[i]["id"],
Code = dt.Rows[i]["cCode"].ToString()
} ;
MidEvent(ai, null);
}
EndEvent(dt.Rows.Count, null);
}
}
}
catch (Exception e)
{
EEvent(e.Message, null);
}
}
}
public class a
{
public int ID { get; set; }
public String Code { get; set; } = "";
}
View Code
3.4 代码3.2
private void button6_Click(object sender, EventArgs e)
{
WeiTuo wt = new WeiTuo();
wt.StartEvent += Wt_StartEvent;
wt.MidEvent += Wt_MidEvent;
wt.EndEvent += Wt_EndEvent;
wt.EEvent += Wt_EEvent;
Thread th = new Thread(wt.ExecEvent);
th.Start();
}
//特殊委托 action
private void Wt_StartEvent(object sender, EventArgs e)
{
Action setLVItem = (s) => { listView1.Items.Add(s); };
this.Invoke(setLVItem, sender.ToString());
}
//特殊委托 action
private void Wt_MidEvent(object sender, EventArgs e)
{
Action setLVItem = (s) => { listView1.Items.Add(s); };
this.Invoke(setLVItem, ((a)sender).Code);
}
#region 委托实现
private void Wt_EndEvent(object sender, EventArgs e)
{
this.Invoke(new setLVItem(setEndValue), "成功");
}
delegate void setLVItem(string s);
void setEndValue(string s)
{
MessageBox.Show(s);
}
#endregion
private void Wt_EEvent(object sender, EventArgs e)
{
Action ShowBox = (s) => { MessageBox.Show(s); };
this.Invoke(ShowBox, sender.ToString());
}
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3.5 结果如下图
task任务与thread大同小异 使用时 尽量少的让控件跨线程 可通过ref 或 out 对参数传出 检测线程结束 再给控件赋值 也可用task的wait方法 4 异步回调
private void button1_Click(object sender, EventArgs e)
{
Func Sum = (i, j) =>
{
Thread.Sleep(3000);
return i + j;
};
listView1.Items.Add("开始");
IAsyncResult iar = Sum.BeginInvoke(1, 2, CallbackWhenDone, "我是测试");
listView1.Items.Add("over");
}
private void CallbackWhenDone(IAsyncResult iar)
{
AsyncResult ar = (AsyncResult)iar;
Func f = (Func)ar.AsyncDelegate;
Action a = (lv) =>
{
lv.Items.Add(ar.AsyncState.ToString());
lv.Items.Add(f.EndInvoke(iar).ToString());
};
this.Invoke( a,listView1);
}
View Code
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