我有一个设想。(Windows Forms, c#， .NET)
There is a main form which hosts some user control. The user control does some heavy data operation, such that if I directly call the UserControl_Load method the UI become nonresponsive for the duration for load method execution. To overcome this I load data on different thread (trying to change existing code as little as I can) I used a background worker thread which will be loading the data and when done will notify the application that it has done its work. Now came a real problem. All the UI (main form and its child usercontrols) was created on the primary main thread. In the LOAD method of the usercontrol I'm fetching data based on the values of some control (like textbox) on userControl.
伪代码看起来像这样:
代码1
UserContrl1_LoadDataMethod()
{
if (textbox1.text == "MyName") // This gives exception
{
//Load data corresponding to "MyName".
//Populate a globale variable List<string> which will be binded to grid at some later stage.
}
}
它给出的例外是
跨线程操作无效:从创建该控件的线程以外的线程访问的控件。
为了了解更多关于这一点，我做了一些谷歌搜索，并提出了一个建议，如使用以下代码
代码2
UserContrl1_LoadDataMethod()
{
if (InvokeRequired) // Line #1
{
this.Invoke(new MethodInvoker(UserContrl1_LoadDataMethod));
return;
}
if (textbox1.text == "MyName") // Now it won't give an exception
{
//Load data correspondin to "MyName"
//Populate a globale variable List<string> which will be binded to grid at some later stage
}
}
但我似乎还是回到了原点。再次申请 变得反应迟钝。这似乎是由于第1行if条件的执行。加载任务再次由父线程完成，而不是由我生成的第三个线程完成。
我不知道我认为这是对还是错。
我如何解决这个问题，以及执行第1行if块的效果是什么?
情况是这样的:我想根据控件的值将数据加载到全局变量中。我不想改变子线程中控件的值。我不会从子线程中做。
因此只有访问值，才能从数据库中获取相应的数据。
