Task - Asynchronously Reading Files
In the previous section, we learned about a file reading method called File.ReadAllText. While it is a synchronous method for reading a file, there is an asynchronous alternative as well - It is called File.ReadAllTextAsync.
There is an attached file in the task description. This is the file we want to read. The base code contains a program that reads the file synchronously.
Task:
Currently, the output of the program is:
Notice how <<ASYNC CHECK>> is only printed after the file is fully read. We want it to print while the file is being read.
Your task is to modify the code and make the program asynchronously read the file.
If the << ASYNC CHECK >> message prints between Started Reading File and Ended Reading File messages, then it means you have successfully implemented an asynchronous solution:
async keyword to convert the ReadFile method into an asynchronous method. 2. The return value of the
ReadFile method will follow the Task syntax where T will represent the datatype of the return value - In this case the return datatype is string. 3. We need to
await the execution of the File.ReadAllTextAsync method inside the ReadFile method. 4. We also need to make the main method asynchronous.
5. Before ending the program, we need to make sure the file reading task is fully performed. For that we can again use the
await keyword.
public class AsyncOutput
{
// Set the file path to the file you downloaded here
public static string filePath = "your\\file\\path\\here.txt";
public static async Task Main()
{
Console.WriteLine("Started Program");
Task fileReadingTask = ReadFile(filePath);
Console.WriteLine("<< ASYNC CHECK >>");
await fileReadingTask;
Console.WriteLine("Ended Program");
}
public static async Task ReadFile(string fileName)
{
Console.WriteLine("Started Reading File");
string text = await File.ReadAllTextAsync(fileName);
Console.WriteLine("Ended Reading File");
}
}
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Зміст курсу
Introduction to .NET with C#
2. Asynchronous Programming and Introduction to Web Services
3. Introduction to Databases with .NET
Introduction to .NET with C#
Task - Asynchronously Reading Files
In the previous section, we learned about a file reading method called File.ReadAllText. While it is a synchronous method for reading a file, there is an asynchronous alternative as well - It is called File.ReadAllTextAsync.
There is an attached file in the task description. This is the file we want to read. The base code contains a program that reads the file synchronously.
Task:
Currently, the output of the program is:
Notice how <<ASYNC CHECK>> is only printed after the file is fully read. We want it to print while the file is being read.
Your task is to modify the code and make the program asynchronously read the file.
If the << ASYNC CHECK >> message prints between Started Reading File and Ended Reading File messages, then it means you have successfully implemented an asynchronous solution:
async keyword to convert the ReadFile method into an asynchronous method. 2. The return value of the
ReadFile method will follow the Task syntax where T will represent the datatype of the return value - In this case the return datatype is string. 3. We need to
await the execution of the File.ReadAllTextAsync method inside the ReadFile method. 4. We also need to make the main method asynchronous.
5. Before ending the program, we need to make sure the file reading task is fully performed. For that we can again use the
await keyword.
public class AsyncOutput
{
// Set the file path to the file you downloaded here
public static string filePath = "your\\file\\path\\here.txt";
public static async Task Main()
{
Console.WriteLine("Started Program");
Task fileReadingTask = ReadFile(filePath);
Console.WriteLine("<< ASYNC CHECK >>");
await fileReadingTask;
Console.WriteLine("Ended Program");
}
public static async Task ReadFile(string fileName)
{
Console.WriteLine("Started Reading File");
string text = await File.ReadAllTextAsync(fileName);
Console.WriteLine("Ended Reading File");
}
}
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