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Sign inTextReader.ReadLineAsync Method
Definition
Important
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Overloads
| ReadLineAsync() |
Reads a line of characters asynchronously and returns the data as a string. |
| ReadLineAsync(CancellationToken) |
Reads a line of characters asynchronously and returns the data as a string. |
- Source:
- TextReader.cs
- Source:
- TextReader.cs
- Source:
- TextReader.cs
- Source:
- TextReader.cs
Reads a line of characters asynchronously and returns the data as a string.
public:
virtual System::Threading::Tasks::Task<System::String ^> ^ ReadLineAsync();public virtual System.Threading.Tasks.Task<string> ReadLineAsync();public virtual System.Threading.Tasks.Task<string?> ReadLineAsync();[System.Runtime.InteropServices.ComVisible(false)]
public virtual System.Threading.Tasks.Task<string> ReadLineAsync();abstract member ReadLineAsync : unit -> System.Threading.Tasks.Task<string>
override this.ReadLineAsync : unit -> System.Threading.Tasks.Task<string>[<System.Runtime.InteropServices.ComVisible(false)>]
abstract member ReadLineAsync : unit -> System.Threading.Tasks.Task<string>
override this.ReadLineAsync : unit -> System.Threading.Tasks.Task<string>Public Overridable Function ReadLineAsync () As Task(Of String)Returns
A task that represents the asynchronous read operation. The value of the TResult parameter contains the next line from the text reader, or is null if all of the characters have been read.
- Attributes
Exceptions
The number of characters in the next line is larger than Int32.MaxValue.
The text reader has been disposed.
The reader is currently in use by a previous read operation.
Remarks
The TextReader class is an abstract class. Therefore, you do not instantiate it in your code. For an example of using the ReadLineAsync method, see the StreamReader.ReadLineAsync method.
If the current TextReader represents the standard input stream returned by the Console.In property, the ReadLineAsync method executes synchronously rather than asynchronously.
This method stores in the task it returns all non-usage exceptions that the method's synchronous counterpart can throw. If an exception is stored into the returned task, that exception will be thrown when the task is awaited. Usage exceptions, such as ArgumentException, are still thrown synchronously. For the stored exceptions, see the exceptions thrown by ReadLine().
See also
- ReadLineAsync()
- ReadLineAsync()
- File and Stream I/O
- How to: Read Text from a File
- How to: Write Text to a File
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
| UWP | 10.0 |
- Source:
- TextReader.cs
- Source:
- TextReader.cs
- Source:
- TextReader.cs
- Source:
- TextReader.cs
Reads a line of characters asynchronously and returns the data as a string.
public:
virtual System::Threading::Tasks::ValueTask<System::String ^> ReadLineAsync(System::Threading::CancellationToken cancellationToken);public virtual System.Threading.Tasks.ValueTask<string?> ReadLineAsync(System.Threading.CancellationToken cancellationToken);abstract member ReadLineAsync : System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<string>
override this.ReadLineAsync : System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<string>Public Overridable Function ReadLineAsync (cancellationToken As CancellationToken) As ValueTask(Of String)Parameters
- cancellationToken
- CancellationToken
The token to monitor for cancellation requests.
Returns
A value task that represents the asynchronous read operation. The value of the TResult parameter contains the next line from the text reader, or is null if all of the characters have been read.
Exceptions
The number of characters in the next line is larger than Int32.MaxValue.
The text reader has been disposed.
The reader is currently in use by a previous read operation.
The cancellation token was canceled. This exception is stored into the returned task.
Remarks
The TextReader class is an abstract class. Therefore, you do not instantiate it in your code. For an example of using the ReadLineAsync(CancellationToken) method, see the ReadLineAsync(CancellationToken) method.
If the current TextReader represents the standard input stream returned by
the Console.In property, the ReadLineAsync(CancellationToken) method
executes synchronously rather than asynchronously.
This method stores in the task it returns all non-usage exceptions that the method's synchronous counterpart can throw. If an exception is stored into the returned task, that exception will be thrown when the task is awaited. Usage exceptions, such as ArgumentException, are still thrown synchronously. For the stored exceptions, see the exceptions thrown by ReadLine().
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | 7, 8, 9, 10 |