牧童蝉网站建设/处理器优化软件
访问 Windows 窗体控件本质上不是线程安全的。如果有两个或多个线程操作某一控件的状态,则可能会迫使该控件进入一种不一致的状态。还可能出现其他与线程相关的 bug,包括争用情况和死锁。确保以线程安全方式访问控件非常重要。
解决办法
1、把CheckForIllegalCrossThreadCalls设置为false
在多线程程序中,新创建的线程不能访问UI线程创建的窗口控件,如果需要访问窗口中的控件,可以在窗口构造函数中将CheckForIllegalCrossThreadCalls设置为 false
public Form1()
{InitializeComponent();CheckForIllegalCrossThreadCalls = false;
}
也可以针对某一控件进行设置,例如:
TextBox.CheckForIllegalCrossThreadCalls = false;
2、利用委托
delegate void SetTextCallBack(string text);private void SetText(string text){if (this.txt_a.InvokeRequired){SetTextCallBack stcb = new SetTextCallBack(SetText);this.Invoke(stcb , new object[] { text});}else{this.txt_a.Text = text;}}private void LoadData(){SetText("测试");}//窗体加载时,用线程加载数据private void Frm_ImportManager_Load(object sender, EventArgs e){ThreadStart ts = new ThreadStart(LoadData);Thread thread = new Thread(ts);thread.Name = "LoadData";thread.Start();}
3、使用 BackgroundWorker控件
在应用程序中实现多线程的首选方式是使用 BackgroundWorker 组件。BackgroundWorker 组件使用事件驱动模型实现多线程。辅助线程运行 DoWork 事件处理程序,创建控件的线程运行ProgressChanged 和 RunWorkerCompleted 事件处理程序。注意不要从 DoWork 事件处理程序调用您的任何控件。
下面的代码示例不异步执行任何工作,因此没有 DoWork 事件处理程序的实现。TextBox 控件的Text 属性在 RunWorkerCompleted 事件处理程序中直接设置。
// This event handler starts the form's // BackgroundWorker by calling RunWorkerAsync.//// The Text property of the TextBox control is set// when the BackgroundWorker raises the RunWorkerCompleted// event.private void setTextBackgroundWorkerBtn_Click(object sender, EventArgs e){this.backgroundWorker1.RunWorkerAsync();}// This event handler sets the Text property of the TextBox// control. It is called on the thread that created the // TextBox control, so the call is thread-safe.//// BackgroundWorker is the preferred way to perform asynchronous// operations.private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e){this.textBox1.Text = "This text was set safely by BackgroundWorker.";}