執行緒間操作無效: 從不是建立控制元件“progressBar1”的執行緒訪問它
阿新 • • 發佈：2019-01-23
2、建立代理
delegate void SetTextCallback(string text);
建立和啟動執行緒
this.demoThread =
new Thread(new ThreadStart(this.ThreadProcUnsafe));
this.demoThread.Start();
執行緒中要求改主窗體UI中的text屬性
private void ThreadProcSafe()
{
this.SetText("This text was set safely.");
}
呼叫窗體中的函式用invoke傳遞引數
private void SetText(string text)
{
if (this.textBox1.InvokeRequired)
{
SetTextCallback d = new SetTextCallback(SetText);
this.Invoke(d, new object[] { text });
}
else
{
this.textBox1.Text = text;
}
}
3、
{
1.定義 委託
delegatevoid myDelegate(int i);
myDelegate mydelegate =null;
2.定義方法,顯示訊息
publicvoid ShowMessage(int i)
{
this.textBox1.Text = i.ToString();
this.progressBar1.Value = i;
}
3.定義方法,驅動訊息
publicvoid MyEvent()
{
for
{
Thread.Sleep(100);
this.BeginInvoke(mydelegate, newobject[] {i});
}
}
4: 執行
privatevoid button1_Click(object sender, EventArgs e)
{
mydelegate =new myDelegate(ShowMessage);
Thread myThread =new Thread(MyEvent);
//IsBackground 是否後臺
//這個屬性很重要 .如果 Thread IsBackground 等於false
// 當執行緒還沒有結束時，你點了關閉按鈕
// 將丟擲An unhandled exception
//of type 'System.InvalidOperationException'
//occurred in System.Windows.Forms.dll 異常 myThread.IsBackground =true;
myThread.Start();
} }