Interface ITaskHandler
Used to run and track ITasks and ask the user questions. Specific implementations provide different kinds of user interfaces.
public interface ITaskHandler
- Extension Methods
Remarks
Implementations of this interface are thread-safe.
Properties
CancellationToken
Used to signal when the user wants to cancel the entire current process (and any ITasks it includes).
CancellationToken CancellationToken { get; }
Property Value
Remarks
Once this has been signalled this ITaskHandler cannot be reused, since any subsequently started ITasks will be cancelled immediately.
Verbosity
The detail level of messages displayed to the user.
Verbosity Verbosity { get; set; }
Property Value
Methods
Ask(string, bool?, string?)
Asks the user a Yes/No/Cancel question.
bool Ask(string question, bool? defaultAnswer = null, string? alternateMessage = null)
Parameters
question
stringThe question and comprehensive information to help the user make an informed decision.
defaultAnswer
bool?The default answer to preselect. May be chosen automatically if the user cannot be asked.
null
if the user must make the choice themselves.alternateMessage
stringA message to output with Warn(string, Exception?) when the
defaultAnswer
is used instead of asking the user.
Returns
- bool
true
if the user answered with 'Yes';false
if the user answered with 'No'.
Exceptions
- OperationCanceledException
Throw if the user answered with 'Cancel' or if no answer can be obtained.
Error(Exception)
Displays an error message to the user.
void Error(Exception exception)
Parameters
exception
ExceptionThe exception representing the error that occurred.
Output(string, string)
Displays multi-line text to the user.
void Output(string title, string message)
Parameters
title
stringA title for the message.
message
stringThe string to display. Trailing linebreaks are appropriately handled or ignored.
Remarks
Implementations may close the UI as a side effect. Therefore this should be your last call on the handler.
Output<T>(string, NamedCollection<T>)
Displays tree-like data to the user.
void Output<T>(string title, NamedCollection<T> data) where T : INamed
Parameters
title
stringA title for the data.INamed
data
NamedCollection<T>The data to display.
Type Parameters
T
Remarks
Implementations may close the UI as a side effect. Therefore this should be your last call on the handler.
Output<T>(string, IEnumerable<T>)
Displays tabular data to the user.
void Output<T>(string title, IEnumerable<T> data)
Parameters
title
stringA title for the data.
data
IEnumerable<T>The data to display.
Type Parameters
T
Remarks
Implementations may close the UI as a side effect. Therefore this should be your last call on the handler.
RunTask(ITask)
Runs an ITask and tracks its progress. Returns once the task has been completed.
void RunTask(ITask task)
Parameters
task
ITaskThe task to be run. (Run(CancellationToken, ICredentialProvider?, IProgress<TaskSnapshot>?) or equivalent is called on it.)
Exceptions
- OperationCanceledException
The user canceled the task.
- IOException
The task ended with IOError.
- WebException
The task ended with WebError.