使用Winforms和C#在继续时更新文本框
本文关键字:更新 文本 继续 Winforms 使用 | 更新日期: 2023-09-27 17:59:50
C#noob,来自其他语言的经验。(最著名的是Java)。
我在看这个问题的代码。这是VS 2013中的标准WinForms C#项目:
在表单上放置一个按钮和一个文本框,然后使用以下代码:
private void button1_Click(object sender, EventArgs e)
{
Task.Factory.StartNew<int>(() => DelayedAdd(5, 10))
.ContinueWith(t => DelayedAdd(t.Result, 20))
.ContinueWith(t => DelayedAdd(t.Result, 30))
.ContinueWith(t => DelayedAdd(t.Result, 50))
.ContinueWith(t => textBox1.Text = t.Result.ToString(),
TaskScheduler.FromCurrentSynchronizationContext());
}
private int DelayedAdd(int a, int b)
{
Thread.Sleep(500);
return a + b;
}
按下按钮,等待2秒钟,等待四个DelayedAdd
调用完成,结果(115)显示在文本框中如何在每次DelayedAdd
调用后在文本框中显示结果
,我试着在每次通话之间推最后一个继续
Task.Factory.StartNew<int>(() => DelayedAdd(5, 10))
.ContinueWith(t => textBox1.Text = t.Result.ToString(),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 20))
.ContinueWith(t => textBox1.Text = t.Result.ToString(),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 30))
.ContinueWith(t => textBox1.Text = t.Result.ToString(),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 50))
.ContinueWith(t => textBox1.Text = t.Result.ToString(),
TaskScheduler.FromCurrentSynchronizationContext());
但是失败了,我猜是因为我插入的continuation没有返回整数结果t
。我是一个C#noob,我甚至不知道如何修复,更不用说用惯用的方法了。
我只想更改DelayedAdd
方法:
private void button1_Click(object sender, EventArgs e)
{
Task.Factory.StartNew<int>(() => DelayedAdd(5, 10))
.ContinueWith(t => DelayedAdd(t.Result, 20))
.ContinueWith(t => DelayedAdd(t.Result, 30))
.ContinueWith(t => DelayedAdd(t.Result, 50));
}
private int DelayedAdd(int a, int b)
{
if (textBox1.InvokeRequired)
{
textBox1.BeginInvoke((Action)(() => textBox1.Text = (a + b).ToString()));
}
Thread.Sleep(500);
return a + b;
}
明白了!如果有人有更好/更有趣的选择,请回答。
首先,我尝试了一个多行lambda来代替问题中的错误延续
.ContinueWith(t => {
textBox1.Text = t.Result.ToString();
return t.Result;
},
TaskScheduler.FromCurrentSynchronizationContext());
}
这有点冗长和重复,所以我把它整理了一下:
private void button1_Click(object sender, EventArgs e)
{
// SCHEDULING LOGIC
Task.Factory.StartNew<int>(() => DelayedAdd(5, 10))
.ContinueWith(t => UpdateText(t.Result),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 20))
.ContinueWith(t => UpdateText(t.Result),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 30))
.ContinueWith(t => UpdateText(t.Result),
TaskScheduler.FromCurrentSynchronizationContext())
.ContinueWith(t => DelayedAdd(t.Result, 50))
.ContinueWith(t => UpdateText(t.Result),
TaskScheduler.FromCurrentSynchronizationContext());
}
private int UpdateText(int i)
{
// UI LOGIC
textBox1.Text = i.ToString();
return i;
}
private int DelayedAdd(int a, int b)
{
// PROCESS LOGIC
Thread.Sleep(500);
return a + b;
}