---
product: Chilkat
product_version: 11.7.0
language: csharp
language_label: C#
class: ZipCrc
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/csZipCrcRef.html
---
# Chilkat ZipCrc — C# — v11.7.0

> Chilkat 11.7.0 · language=csharp · class=ZipCrc
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/ZipCrc.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/guide.md`.

## Purpose

**Calculate ZIP-compatible CRC32 values for files, bytes, strings, and streamed data.**

`Chilkat.ZipCrc` calculates the 32-bit CRC value used in ZIP file headers. It can compute CRC32 values for in-memory byte arrays, `BinData`, `StringBuilder` content, strings using a specified character encoding, and entire files. It also supports streaming CRC calculation, allowing applications to process large or incremental data in chunks without holding the full input in memory.

**CRC32 for byte data**

Use `CalculateCrc` to calculate a ZIP-style CRC32 value for an in-memory byte array.

**BinData support**

Use `CrcBd` when the input bytes are already stored in a `Chilkat.BinData` object.

**String CRCs**

Use `CrcString` or `CrcSb` to calculate CRC32 for text using a specific charset such as `utf-8`, `utf-16`, or `windows-1252`.

**File CRCs**

Use `FileCrc` to calculate the CRC32 of a file while streaming the file contents to keep memory usage small and constant.

**Streaming calculation**

Call `BeginStream`, add chunks with `MoreData`, and finish with `EndStream` when data arrives incrementally.

**Hex formatting**

Use `ToHex` to convert a 32-bit CRC integer into a readable hexadecimal string.

**Common pattern:** Use `FileCrc` for files, `CalculateCrc` or `CrcBd` for binary data already in memory, and `CrcString` or `CrcSb` for text where the byte representation depends on a charset. For large or chunked input, initialize the CRC with `BeginStream`, feed each block with `MoreData`, and call `EndStream` to obtain the final CRC32 value.

**ZIP compatibility note:** The CRC returned by this class is the same 32-bit CRC value that would appear in a ZIP file header for the same byte content. When calculating CRCs for strings, the selected charset matters because the CRC is computed over bytes, not abstract characters.

## Object creation, unlocking and error handling

**Object Creation**

```csharp
Chilkat.ZipCrc obj = new Chilkat.ZipCrc();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in C#.

Minimal complete program:

```csharp
// Required once per process. Any string unlocks a 30-day trial; use your purchased code in production.
Chilkat.Global glob = new Chilkat.Global();
if (!glob.UnlockBundle("Anything for 30-day trial"))
{
    Console.WriteLine(glob.LastErrorText);
    return;
}

Chilkat.ZipCrc zipCrc = new Chilkat.ZipCrc();
```

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `public string DebugLogFilePath {get; set; }` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `public string LastErrorHtml {get; }` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `public string LastErrorText {get; }` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `public string LastErrorXml {get; }` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `public bool LastMethodSuccess {get; set; }` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `public bool VerboseLogging {get; set; }` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `public string Version {get; }` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `BeginStream` | method | `public void BeginStream();` |
| `CalculateCrc` | method | `public uint CalculateCrc(byte[] data);` |
| `CrcBd` | method | `public uint CrcBd(BinData bd);` |
| `CrcSb` | method | `public uint CrcSb(StringBuilder sb, string charset);` |
| `CrcString` | method | `public uint CrcString(string str, string charset);` |
| `EndStream` | method | `public uint EndStream();` |
| `FileCrc` | method | `public uint FileCrc(string path);` |
| `LoadTaskCaller` | method | `public bool LoadTaskCaller(Task task);` |
| `MoreData` | method | `public void MoreData(byte[] data);` |
| `ToHex` | method | `public string ToHex(uint crc);` |

## Methods

### ZipCrc.BeginStream

`Chilkat 11.7.0 · csharp · ZipCrc · BeginStream · method`

```csharp
public void BeginStream();
```

Provides a way to calculate a CRC by streaming the data a chunk at a time. An application would start by calling BeginStream. Then it would add data by calling MoreData for each additional chunk. After the last chunk has been processed, the EndStream method is called to return the CRC.

### ZipCrc.CalculateCrc

`Chilkat 11.7.0 · csharp · ZipCrc · CalculateCrc · method`

```csharp
public uint CalculateCrc(byte[] data);
```

Calculates a 32-bit CRC for in-memory byte data. This is the 32-bit CRC that would be found in a Zip file header if a file containing the `data` was added to a zip archive. Returns the CRC32 of the data.

### ZipCrc.CrcBd

`Chilkat 11.7.0 · csharp · ZipCrc · CrcBd · method · since 9.5.0.75`

```csharp
public uint CrcBd(BinData bd);
```

Calculates a CRC32 for the bytes contained in `bd`.

### ZipCrc.CrcSb

`Chilkat 11.7.0 · csharp · ZipCrc · CrcSb · method · since 9.5.0.75`

```csharp
public uint CrcSb(StringBuilder sb, string charset);
```

Calculates a CRC32 for the string contained in `sb`. The `charset` is the byte representation to be used for the `sb` when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

### ZipCrc.CrcString

`Chilkat 11.7.0 · csharp · ZipCrc · CrcString · method · since 9.5.0.75`

```csharp
public uint CrcString(string str, string charset);
```

Calculates a CRC32 for a string. The `charset` is the byte representation to be used for the `str` when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

### ZipCrc.EndStream

`Chilkat 11.7.0 · csharp · ZipCrc · EndStream · method`

```csharp
public uint EndStream();
```

Finalizes and returns the Zip CRC value calculated by calling BeginStream followed by multiple calls to MoreData.

### ZipCrc.FileCrc

`Chilkat 11.7.0 · csharp · ZipCrc · FileCrc · method`

```csharp
public uint FileCrc(string path);
```

Calculates the CRC32 of a file. The data contained in the file is streamed for the calculation to keep the memory footprint small and constant. Returns the CRC32 of the file.

Async variant: `FileCrcAsync` — same arguments, returns a `Task` (see Async variants below).

### ZipCrc.LoadTaskCaller

`Chilkat 11.7.0 · csharp · ZipCrc · LoadTaskCaller · method · since 9.5.0.80`

```csharp
public bool LoadTaskCaller(Task task);
```

Loads the caller of the task's async method.

Returns true for success, false for failure.

### ZipCrc.MoreData

`Chilkat 11.7.0 · csharp · ZipCrc · MoreData · method`

```csharp
public void MoreData(byte[] data);
```

Adds additional data to the CRC currently being calculated. (See BeginStream for more information.)

### ZipCrc.ToHex

`Chilkat 11.7.0 · csharp · ZipCrc · ToHex · method`

```csharp
public string ToHex(uint crc);
```

Converts a 32-bit integer to a hex string.

Returns `null` on failure

## Events and callbacks

### ZipCrc.AbortCheck (event)

`Chilkat 11.7.0 · csharp · ZipCrc · AbortCheck · event`

```csharp
public event AbortCheckEventHandler OnAbortCheck;
```

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the `HeartbeatMs` property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.AbortCheckEventArgs

**Event callback implementation:**

```csharp
private void zipcrc_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
zipcrc.OnAbortCheck += zipcrc_OnAbortCheck;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleAbortCheck(out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
// ...
Chilkat.ZipCrc.AbortCheck abortCheck = new Chilkat.ZipCrc.AbortCheck(handleAbortCheck);
zipcrc.setAbortCheckCb(abortCheck);
```

### ZipCrc.PercentDone (event)

`Chilkat 11.7.0 · csharp · ZipCrc · PercentDone · event`

```csharp
public event PercentDoneEventHandler OnPercentDone;
```

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The `pctDone` argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have `pctDone` equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an `AbortCheck` event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the `abort` output argument to `true`. This will cause the method to terminate and return a failure status or corresponding failure value.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.PercentDoneEventArgs

**Event callback implementation:**

```csharp
private void zipcrc_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
zipcrc.OnPercentDone += zipcrc_OnPercentDone;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handlePercentDone(int pctDone, out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
// ...
Chilkat.ZipCrc.PercentDone percentDone = new Chilkat.ZipCrc.PercentDone(handlePercentDone);
zipcrc.setPercentDoneCb(percentDone);
```

### ZipCrc.ProgressInfo (event)

`Chilkat 11.7.0 · csharp · ZipCrc · ProgressInfo · event`

```csharp
public event ProgressInfoEventHandler OnProgressInfo;
```

This event callback provides `tag name`/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.ProgressInfoEventArgs

**Event callback implementation:**

```csharp
private void zipcrc_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
zipcrc.OnProgressInfo += zipcrc_OnProgressInfo;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleProgressInfo(string name, string value)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
// ...
Chilkat.ZipCrc.ProgressInfo progressInfo = new Chilkat.ZipCrc.ProgressInfo(handleProgressInfo);
zipcrc.setProgressInfoCb(progressInfo);
```

### ZipCrc.TaskCompleted (event)

`Chilkat 11.7.0 · csharp · ZipCrc · TaskCompleted · event`

```csharp
public event TaskCompletedEventHandler OnTaskCompleted;
```

Called from the background thread when an asynchronous task completes.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.TaskCompletedEventArgs

**Event callback implementation:**

```csharp
private void zipcrc_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
zipcrc.OnTaskCompleted += zipcrc_OnTaskCompleted;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleTaskIdCompleted(int taskId)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.ZipCrc zipcrc = new Chilkat.ZipCrc();
// ...
Chilkat.ZipCrc.TaskIdCompleted taskIdCompleted = new Chilkat.ZipCrc.TaskIdCompleted(handleTaskIdCompleted);
zipcrc.setTaskIdCompletedCb(taskIdCompleted);
```

## Async variants

Each returns a `Task` instead of the result and takes the same arguments as the synchronous method; run the task, wait for `Finished`, then read the result from the task. No new Async methods are added from 11.7.0 on.

```csharp
public Task FileCrcAsync(string path);
```

## Related classes

[`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/BinData.md), [`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/StringBuilder.md), [`Task`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/Task.md)