Method Retry
| Edit this pageRetry<TSource>(IEnumerable<TSource>)
Creates a sequence that retries enumerating the source sequence as long as an error occurs.
Declaration
public static IEnumerable<TSource> Retry<TSource>(this IEnumerable<TSource> source)Parameters
| Type | Name | Description |
|---|---|---|
| IEnumerable<TSource> | source | Source sequence. |
Returns
| Type | Description |
|---|---|
| IEnumerable<TSource> | Sequence concatenating the results of the source sequence as long as an error occurs. |
Type Parameters
| Name | Description |
|---|---|
| TSource | Source sequence element type. |
Remarks
source will be enumerated and values streamed until it either completes or encounters an
error. If an error is thrown, then source will be re-enumerated from the beginning. This
will happen until an iteration of source has completed without errors.
This method uses deferred execution and streams its results.
Examples
The following code example demonstrates how to retry sequences on failure using Retry.
// this sequence will throw an exception on the 4th element
var sequence = Enumerable.Range(1, 3)
.Concat(SuperEnumerable.Throw<int>(new InvalidOperationException()));
// Re-enumerate the sequence on failure indefinitely
var result = sequence
.Retry()
.Take(12);
Console.WriteLine(
"[" +
string.Join(", ", result) +
"]");
// This code produces the following output:
// [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
Exceptions
| Type | Condition |
|---|---|
| ArgumentNullException |
|
Retry<TSource>(IEnumerable<TSource>, int)
Creates a sequence that retries enumerating the source sequence as long as an error occurs, with the specified maximum number of retries.
Declaration
public static IEnumerable<TSource> Retry<TSource>(this IEnumerable<TSource> source, int count)Parameters
| Type | Name | Description |
|---|---|---|
| IEnumerable<TSource> | source | Source sequence. |
| int | count | Maximum number of retries. |
Returns
| Type | Description |
|---|---|
| IEnumerable<TSource> | Sequence concatenating the results of the source sequence as long as an error occurs. |
Type Parameters
| Name | Description |
|---|---|
| TSource | Source sequence element type. |
Remarks
source will be enumerated and values streamed until it either completes or encounters an
error. If an error is thrown, then source will be re-enumerated from the beginning. This
will happen until an iteration of source has completed without errors, or source has been enumerated count times. If an error is thrown during the final
iteration, it will not be caught and will be thrown to the consumer.
This method uses deferred execution and streams its results.
Examples
The following code example demonstrates how to retry sequences on failure using Retry.
// this sequence will throw an exception on the 4th element
var sequence = Enumerable.Range(1, 3)
.Concat(SuperEnumerable.Throw<int>(new InvalidOperationException()));
// Re-enumerate the sequence on failure up to n times
var result = sequence
.Retry(5)
.Take(12);
Console.WriteLine(
"[" +
string.Join(", ", result) +
"]");
// This code produces the following output:
// [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
Exceptions
| Type | Condition |
|---|---|
| ArgumentNullException |
|
| ArgumentOutOfRangeException |
|