Why SynchronizationContext is so important
suggest changeConsider this example:
private void button1_Click(object sender, EventArgs e)
{
label1.Text = RunTooLong();
}
This method will freeze UI application until the RunTooLong
will be completed. The application will be unresponsive.
You can try run inner code asynchronously:
private void button1_Click(object sender, EventArgs e)
{
Task.Run(() => label1.Text = RunTooLong());
}
But this code won’t execute because inner body may be run on non-UI thread and it shouldn’t change UI properties directly:
private void button1_Click(object sender, EventArgs e)
{
Task.Run(() =>
{
var label1Text = RunTooLong();
if (label1.InvokeRequired)
lable1.BeginInvoke((Action) delegate() { label1.Text = label1Text; });
else
label1.Text = label1Text;
});
}
Now don’t forget always to use this pattern. Or, try SynchronizationContext.Post
that will make it for you:
private void button1_Click(object sender, EventArgs e)
{
Task.Run(() =>
{
var label1Text = RunTooLong();
SynchronizationContext.Current.Post((obj) =>
{
label1.Text = label1 Text);
}, null);
});
}
Found a mistake? Have a question or improvement idea?
Let me know.
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