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[英]How can I display a loading image, or a progress bar, for a new tab while waiting for the MVC call to return?
[英]How can I display a loading control while a process is waiting for be finished?
我决定使用这个第三方组件在我的Windows窗体中进行简单的加载控制。
http://www.codeproject.com/Articles/14841/How-to-write-a-loading-circle-animation-in-NET
打开和关闭时,这在单个请求中将属性“Active”更改为true或false(每次一个)时工作正常。 问题是当进程等待服务时,我假装在进程启动之前激活loadingControl,当我“认为”该进程必须完成时关闭。 当我这样做时,图像加载显示为静态图像。 (没有动画)。
对不起这个问题,我是C#的新手。 但我认为我需要使用Threads或类似的东西。
所以我的一般代码是这样的:
using [libraries here]...;
namespace [namespace here]
{
Public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.loadingCircle1.Visible = false;
}
private void button1_Click(object sender, EventArgs e)
{
Thread t = new Thread(new ThreadStart(showLoading));
this.loadingCircle1.Visible = true;
t.Start();
//Import an Excel
t.Abort();
}
public void showLoading()
{
loadingCircle1.Active = true;
loadingCircle1.RotationSpeed = 10;
}
}
}
但始终加载显示为没有动画的静态图像。
您创建一个线程,它只是设置两个属性然后结束。 t.Abort
可能什么都不做,因为那个时候线程已经退出了。 更糟糕的是,您在UI线程上导入excel文件,该文件会阻止任何动画并冻结整个UI。
这就是你应该如何做到的:
备注:当然,如果您的表单是响应式的,您必须禁用/启用控件并准备好在加载过程中关闭表单时会发生什么情况。
1.使用线程
如果你真的想显式使用线程,那就这样做:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private Thread workerThread = null;
private void btnImport_Click(object sender, EventArgs e)
{
// start the animation (I used a progress bar, start your circle here)
progressBar1.Visible = true;
progressBar1.Style = ProgressBarStyle.Marquee;
// start the job and the timer, which polls the thread
btnImport.Enabled = false;
workerThread = new Thread(LoadExcel);
workerThread.Start();
timer1.Interval = 100;
timer1.Start();
}
private void LoadExcel()
{
// some work takes 5 sec
Thread.Sleep(5000);
}
private void timer1_Tick(object sender, EventArgs e)
{
if (workerThread == null)
{
timer1.Stop();
return;
}
// still works: exiting
if (workerThread.IsAlive)
return;
// finished
btnImport.Enabled = true;
timer1.Stop();
progressBar1.Visible = false;
workerThread = null;
}
}
2.背景工作者
BackgroundWorker
可以在完成时抛出一个事件:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
backgroundWorker1.DoWork += BackgroundWorker1_DoWork;
backgroundWorker1.RunWorkerCompleted += BackgroundWorker1_RunWorkerCompleted;
}
private void btnImport_Click(object sender, EventArgs e)
{
// start the animation
progressBar1.Visible = true;
progressBar1.Style = ProgressBarStyle.Marquee;
// start the job
btnImport.Enabled = false;
backgroundWorker1.RunWorkerAsync();
}
private void BackgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
LoadExcel();
}
private void BackgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
btnImport.Enabled = true;
progressBar1.Visible = false;
}
private void LoadExcel()
{
// some work takes 5 sec
Thread.Sleep(5000);
}
}
3.使用async-await
这是最简单的一个。
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private async void btnImport_Click(object sender, EventArgs e)
{
// start the waiting animation
progressBar1.Visible = true;
progressBar1.Style = ProgressBarStyle.Marquee;
// simply start and await the loading task
btnImport.Enabled = false;
await Task.Run(() => LoadExcel());
// re-enable things
btnImport.Enabled = true;
progressBar1.Visible = false;
}
private void LoadExcel()
{
// some work takes 5 sec
Thread.Sleep(5000);
}
}
我建议使用async / await(对于C#5.0):
private void button1_Click(object sender, EventArgs e){
ImportAsync();
}
private async Task ImportAsync(){
// UI-thread
showLoading();
this.loadingCircle1.Visible = true;
// wait until task will be finished
await Task.Run(() => {
// different non-blocking thread for all the hard work, but without UI-stuff
// import an Excel
});
// going back to UI-thread
this.loadingCircle1.Visible = false;
}
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