C Encountered such a problem in programming

If you use multithreading, you can, sleep in another thread, and then use the delegate to solve the main thread to change the lable text.

Here's how to name your lable as lable1

using ;

Runs when the main form loads.

private void form1_load(object sender, eventargs e)

thread t = new thread(new threadstart(delegate()

region[ new thread ].

Functions that run with a new thread.

public void runbynewth()

text;#endregion

This kind of thread delegation also has certain limitations, such as when the main thread is busy, the delegation will be postponed, that is, the time set in the delegation may not be very accurate.

The latest version. There are async and await, which can easily solve this problem.

Old. net can try to access the main thread's controls with an invoke delegate:

Suppose the label name is label1.

First, create a new delegate:

private delegate void modlabeltext(string msg);

Then build a method to have the main thread modify the label:

private void modlabeltext(string message)

if (modlabeltext c = new modlabeltext(modlabeltext);

new object

message;

Next, build a method for new threads to use:

private void label1sleep()

Let this subthread rest for 1 second.

todo other operations.

modlabeltext("You're good too");

Finally, you can change the text first, and then wait a second to see, is it changed?

private void button1_click(object sender, eventargs e)

Hello";td = new ;;

= "a";

Or; = "b";

The test has passed.

The reason is that the program has not had time to change the text attribute of lb and has started sleeping, and after sleep is over, b is directly assigned, so what you see is b, so add a sentence to update the control or redraw the control and start sleep after the update or redraw is completed, you can achieve the result you need.

What do you use without timer? You are just coming up with 10,000 ways to still operate threads to implement your functions, timer is a good control, threads are independent, resource sharing! Don't bother with it.

An error is reported due to a usage error. The solution and procedure are as follows:

1. Preferred, open the compiler, and then type edit in the command line to open it, as shown in the following figure.

2. Secondly, after completing the above steps, enter function to indicate that the file is a function file, as shown in the image below.

3. Next, if any return value is entered to the left of the equal sign, use square brackets to indicate multiple return values, as shown in the image below.

4. Then, to the right of the equal sign is the function name plus parentheses, and the parentheses are the parameters, as shown in the following figure.

5. Subsequently, after completing the above steps, use the comment, the first line of the comment is to explain the function of the function as shown in the following image.

6. Then, after completing the above steps, pass the coordinates of the two points, then calculate the distance between the two points, and pass it to the return value y, as shown in the figure below.

7. Finally, after completing the above steps, save the file, and the file name and function name remain unchanged when saving, as shown in the following figure. In this way, the problem is solved.

The two are completely different :

1. Syntax error: Syntax error refers to ** error, which is a compilation error, that is, an error that can be identified at the time of development. ** with compilability errors in C will not compile at all, i.e., you will not be able to build an executable program.

2. Abnormal error: Abnormal error is a runtime error, that is, an error caused by triggering a certain situation during the running of the program, which cannot be found at the time of compilation, and can only be found at the time of running. For example:

a）string s = null; ',');In this case, a nullreference exception will be reported, which tells you that empty objects cannot call the split method. However, at compile time, you don't know whether s is null or not (after all, few people actually write these two sentences together, maybe s is not null halfway through), so there is no error during compilation, and only when it is executed.