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

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

## Purpose

**Upload files with HTTP POST, form fields, headers, progress tracking, and TLS control.**

`Chilkat.Upload` sends files to a web server using HTTP POST, typically as a multipart/form-data upload. It supports one or more file references, custom form parameters, custom HTTP headers, blocking and asynchronous uploads, progress monitoring, upload throttling, Basic HTTP authentication, proxy settings, HTTPS/TLS configuration, timeout control, and inspection of the HTTP response returned by the server.

**File upload requests**

Add one or more local file references and send them to a server endpoint using HTTP POST.

**Form parameters**

Add ordinary form fields alongside file parts when the server expects metadata, tokens, IDs, or other POST parameters.

**Custom headers**

Include application-specific HTTP headers for authorization schemes, API requirements, content negotiation, or server-side routing.

**Blocking or async upload**

Use a simple blocking upload, begin an upload in the background, or use async task-based workflows where supported.

**Progress and throttling**

Monitor bytes sent, percent uploaded, current filename, upload state, and optionally throttle upload bandwidth.

**Authentication, proxy, and TLS**

Configure Basic authentication, HTTP/SOCKS proxy settings, HTTPS/TLS behavior, cipher restrictions, protocol versions, and certificate pinning.

**Common pattern:** Set the server `Hostname`, `Port`, `Ssl`, and upload `Path`, add file references with `AddFileReference`, add any form parameters or headers, then call `BlockingUpload` or start an asynchronous upload. After completion, inspect `ResponseStatus`, `ResponseHeader`, `ResponseBody`, and `LastErrorText` to determine what the server returned.

For an extended overview, see [Upload Class Overview](https://www.chilkatsoft.com/upload_class_overview.asp).

## Object creation, unlocking and error handling

**Object Creation**

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

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.Upload upload = new Chilkat.Upload();
```

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 |
|---|---|---|
| `AbortCurrent` | property, read/write | `public bool AbortCurrent {get; set; }` |
| `BandwidthThrottleUp` | property, read/write | `public int BandwidthThrottleUp {get; set; }` |
| `ChunkSize` | property, read/write | `public int ChunkSize {get; set; }` |
| `ClientIpAddress` | property, read/write | `public string ClientIpAddress {get; set; }` |
| `CurrentFilename` | property, read-only | `public string CurrentFilename {get; }` |
| `Expect100Continue` | property, read/write | `public bool Expect100Continue {get; set; }` |
| `HeartbeatMs` | property, read/write | `public int HeartbeatMs {get; set; }` |
| `Hostname` | property, read/write | `public string Hostname {get; set; }` |
| `IdleTimeoutMs` | property, read/write | `public int IdleTimeoutMs {get; set; }` |
| `Login` | property, read/write | `public string Login {get; set; }` |
| `NumBytesSent` | property, read-only | `public uint NumBytesSent {get; }` |
| `Password` | property, read/write | `public string Password {get; set; }` |
| `Path` | property, read/write | `public string Path {get; set; }` |
| `PercentDoneScale` | property, read/write | `public int PercentDoneScale {get; set; }` |
| `PercentUploaded` | property, read-only | `public uint PercentUploaded {get; }` |
| `Port` | property, read/write | `public int Port {get; set; }` |
| `PreferIpv6` | property, read/write | `public bool PreferIpv6 {get; set; }` |
| `ProxyDomain` | property, read/write | `public string ProxyDomain {get; set; }` |
| `ProxyLogin` | property, read/write | `public string ProxyLogin {get; set; }` |
| `ProxyPassword` | property, read/write | `public string ProxyPassword {get; set; }` |
| `ProxyPort` | property, read/write | `public int ProxyPort {get; set; }` |
| `ResponseBody` | property, read-only | `public byte[] ResponseBody {get; }` |
| `ResponseBodyStr` | property, read-only | `public string ResponseBodyStr {get; }` |
| `ResponseHeader` | property, read-only | `public string ResponseHeader {get; }` |
| `ResponseStatus` | property, read-only | `public int ResponseStatus {get; }` |
| `Ssl` | property, read/write | `public bool Ssl {get; set; }` |
| `SslAllowedCiphers` | property, read/write | `public string SslAllowedCiphers {get; set; }` |
| `SslProtocol` | property, read/write | `public string SslProtocol {get; set; }` |
| `TlsPinSet` | property, read/write | `public string TlsPinSet {get; set; }` |
| `TotalUploadSize` | property, read-only | `public uint TotalUploadSize {get; }` |
| `UploadInProgress` | property, read-only | `public bool UploadInProgress {get; }` |
| `UploadSuccess` | property, read-only | `public bool UploadSuccess {get; }` |
| `AbortUpload` | method | `public void AbortUpload();` |
| `AddCustomHeader` | method | `public void AddCustomHeader(string name, string value);` |
| `AddFileReference` | method | `public void AddFileReference(string name, string filename);` |
| `AddParam` | method | `public void AddParam(string name, string value);` |
| `BeginUpload` | method | `public bool BeginUpload();` |
| `BlockingUpload` | method | `public bool BlockingUpload();` |
| `ClearFileReferences` | method | `public void ClearFileReferences();` |
| `ClearParams` | method | `public void ClearParams();` |
| `LoadTaskCaller` | method | `public bool LoadTaskCaller(Task task);` |
| `SleepMs` | method | `public void SleepMs(int millisec);` |
| `UploadToMemory` | method | `public byte[] UploadToMemory();` |

## Properties

### Upload.AbortCurrent

`Chilkat 11.7.0 · csharp · Upload · AbortCurrent · property · read/write · since 9.5.0.58`

```csharp
public bool AbortCurrent {get; set; }
```

When set to `true`, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to `false` when the next method is called. When the abort occurs, this property is reset to `false`. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

### Upload.BandwidthThrottleUp

`Chilkat 11.7.0 · csharp · Upload · BandwidthThrottleUp · property · read/write · since 9.5.0.49`

```csharp
public int BandwidthThrottleUp {get; set; }
```

If non-zero, limits (throttles) the upload bandwidth to approximately this maximum number of bytes per second. The default value of this property is 0.

### Upload.ChunkSize

`Chilkat 11.7.0 · csharp · Upload · ChunkSize · property · read/write`

```csharp
public int ChunkSize {get; set; }
```

The chunk size (in bytes) used by the underlying TCP/IP sockets for uploading files. The default value is 65535.

### Upload.ClientIpAddress

`Chilkat 11.7.0 · csharp · Upload · ClientIpAddress · property · read/write · since 9.5.0.49`

```csharp
public string ClientIpAddress {get; set; }
```

The IP address to use for computers with multiple network interfaces or IP addresses. For computers with a single network interface (i.e. most computers), this property should not be set. For multihoming computers, the default IP address is automatically used if this property is not set.

The IP address is a string such as in dotted notation using numbers, not domain names, such as `165.164.55.124`.

### Upload.CurrentFilename

`Chilkat 11.7.0 · csharp · Upload · CurrentFilename · property · read-only · since 9.5.0.90`

```csharp
public string CurrentFilename {get; }
```

The current filename being uploaded while an asynchronous upload is in progress.

### Upload.Expect100Continue

`Chilkat 11.7.0 · csharp · Upload · Expect100Continue · property · read/write`

```csharp
public bool Expect100Continue {get; set; }
```

When `true`, the request header will included an `Expect: 100-continue` header field. This indicates that the server should respond with an intermediate response of `100 Continue` or `417 Expectation Failed` response based on the information available in the request header. This helps avoid situations such as limits on upload sizes. It allows the server to reject the upload, and then the client can abort prior to uploading the data.

The default value of this property is `true`.

### Upload.HeartbeatMs

`Chilkat 11.7.0 · csharp · Upload · HeartbeatMs · property · read/write`

```csharp
public int HeartbeatMs {get; set; }
```

**Full documentation for this property (same in every language):** [Event Callback Examples](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/event_callback_examples.md)

The interval in milliseconds between each `AbortCheck` event callback, which enables an application to abort certain method calls before they complete. **By default, HeartbeatMs is set to** `0`**, meaning no AbortCheck event callbacks will trigger.**

### Upload.Hostname

`Chilkat 11.7.0 · csharp · Upload · Hostname · property · read/write`

```csharp
public string Hostname {get; set; }
```

The hostname of the HTTP server that is the target of the upload. Do not include `http://` in the hostname. It can be a hostname, such as `www.chilkatsoft.com`, or an IP address, such as `168.144.70.227`.

### Upload.IdleTimeoutMs

`Chilkat 11.7.0 · csharp · Upload · IdleTimeoutMs · property · read/write`

```csharp
public int IdleTimeoutMs {get; set; }
```

A timeout in milliseconds. The default value is 30000. If the upload hangs (i.e. progress halts) for more than this time, the component will abort the upload. (It will timeout.)

### Upload.Login

`Chilkat 11.7.0 · csharp · Upload · Login · property · read/write`

```csharp
public string Login {get; set; }
```

The HTTP login for sites requiring authentication. Chilkat Upload supports Basic HTTP authentication.

### Upload.NumBytesSent

`Chilkat 11.7.0 · csharp · Upload · NumBytesSent · property · read-only`

```csharp
public uint NumBytesSent {get; }
```

After an upload has completed, this property contains the number of bytes sent. During asynchronous uploads, this property contains the current number of bytes sent while the upload is in progress.

### Upload.Password

`Chilkat 11.7.0 · csharp · Upload · Password · property · read/write`

```csharp
public string Password {get; set; }
```

The HTTP password for sites requiring authentication. Chilkat Upload supports Basic HTTP authentication.

### Upload.Path

`Chilkat 11.7.0 · csharp · Upload · Path · property · read/write`

```csharp
public string Path {get; set; }
```

The path part of the upload URL. Some examples:

desc> If the upload target (i.e. consumer) URL is: http://www.freeaspupload.net/freeaspupload/testUpload.asp, then

> Hostname = `www.freeaspupload.net` Path = `/freeaspupload/testUpload.asp`

If the upload target URL is https://www.chilkatsoft.com/cgi-bin/ConsumeUpload.exe, then

> Hostname = `www.chilkatsoft.com` Path = `/cgi-bin/ConsumeUpload.exe`

### Upload.PercentDoneScale

`Chilkat 11.7.0 · csharp · Upload · PercentDoneScale · property · read/write · since 9.5.0.49`

```csharp
public int PercentDoneScale {get; set; }
```

This property is only valid in programming environment and languages that allow for event callbacks.

Sets the value to be defined as 100% complete for the purpose of PercentDone event callbacks. The defaut value of 100 means that at most 100 event PercentDone callbacks will occur in a method that (1) is event enabled and (2) is such that it is possible to measure progress as a percentage completed. This property may be set to larger numbers to get more fine-grained PercentDone callbacks. For example, setting this property equal to 1000 will provide callbacks with .1 percent granularity. For example, a value of 453 would indicate 45.3% competed. This property is clamped to a minimum value of 10, and a maximum value of 100000.

### Upload.PercentUploaded

`Chilkat 11.7.0 · csharp · Upload · PercentUploaded · property · read-only`

```csharp
public uint PercentUploaded {get; }
```

Contains the current percentage completion (0 to 100) while an asynchronous upload is in progress.

### Upload.Port

`Chilkat 11.7.0 · csharp · Upload · Port · property · read/write`

```csharp
public int Port {get; set; }
```

The port number of the upload target (i.e. consumer) URL. The default value is 80. If SSL is used, this should be set to 443 (typically).

### Upload.PreferIpv6

`Chilkat 11.7.0 · csharp · Upload · PreferIpv6 · property · read/write`

```csharp
public bool PreferIpv6 {get; set; }
```

If `true`, then use IPv6 over IPv4 when both are supported for a particular domain. The default value of this property is `false`, which will choose IPv4 over IPv6.

### Upload.ProxyDomain

`Chilkat 11.7.0 · csharp · Upload · ProxyDomain · property · read/write`

```csharp
public string ProxyDomain {get; set; }
```

The domain name of a proxy host if an HTTP proxy is used. Do not include the `http://`. The domain name may be a hostname, such as `www.chilkatsoft.com`, or an IP address, such as `168.144.70.227`.

### Upload.ProxyLogin

`Chilkat 11.7.0 · csharp · Upload · ProxyLogin · property · read/write`

```csharp
public string ProxyLogin {get; set; }
```

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.

### Upload.ProxyPassword

`Chilkat 11.7.0 · csharp · Upload · ProxyPassword · property · read/write`

```csharp
public string ProxyPassword {get; set; }
```

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.

### Upload.ProxyPort

`Chilkat 11.7.0 · csharp · Upload · ProxyPort · property · read/write`

```csharp
public int ProxyPort {get; set; }
```

The port number of a proxy server if an HTTP proxy is used.

### Upload.ResponseBody

`Chilkat 11.7.0 · csharp · Upload · ResponseBody · property · read-only`

```csharp
public byte[] ResponseBody {get; }
```

An HTTP upload is nothing more than an HTTP POST that contains the content of the files being uploaded. Just as with any HTTP POST or GET, the server should send an HTTP response that consists of header and body.

desc>This property contains the body part of the HTTP response.

### Upload.ResponseBodyStr

`Chilkat 11.7.0 · csharp · Upload · ResponseBodyStr · property · read-only · since 9.5.0.83`

```csharp
public string ResponseBodyStr {get; }
```

Returns the response body as a string.

### Upload.ResponseHeader

`Chilkat 11.7.0 · csharp · Upload · ResponseHeader · property · read-only`

```csharp
public string ResponseHeader {get; }
```

An HTTP upload is nothing more than an HTTP POST that contains the content of the files being uploaded. Just as with any HTTP POST or GET, the server should send an HTTP response that consists of header and body.

desc>This property contains the header part of the HTTP response.

### Upload.ResponseStatus

`Chilkat 11.7.0 · csharp · Upload · ResponseStatus · property · read-only`

```csharp
public int ResponseStatus {get; }
```

The HTTP response status code of the HTTP response. A list of HTTP status codes can be found here: [HTTP Response Status Codes](http://en.wikipedia.org/wiki/List_of_HTTP_status_codes).

### Upload.Ssl

`Chilkat 11.7.0 · csharp · Upload · Ssl · property · read/write`

```csharp
public bool Ssl {get; set; }
```

Set this to `true` if the upload is to HTTPS. For example, if the target of the upload is:

> **https://www.myuploadtarget.com/consumeUpload.asp**

desc>then set:

> Ssl = `true`  
> Hostname = `www.myuploadtarget.com`  
> Path = `/consumeupload.asp`  
> Port = 443

### Upload.SslAllowedCiphers

`Chilkat 11.7.0 · csharp · Upload · SslAllowedCiphers · property · read/write · since 9.5.0.55`

```csharp
public string SslAllowedCiphers {get; set; }
```

Provides a means for setting a list of ciphers that are allowed for SSL/TLS connections. The default (empty string) indicates that all implemented ciphers are possible. The TLS ciphers supported in Chilkat v9.5.0.55 and later are:

```
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA
TLS_ECDHE_RSA_WITH_RC4_128_SHA
TLS_RSA_WITH_RC4_128_SHA
TLS_RSA_WITH_RC4_128_MD5
TLS_DHE_RSA_WITH_DES_CBC_SHA
TLS_RSA_WITH_DES_CBC_SHA
```

To restrict SSL/TLS connections to one or more specific ciphers, set this property to a comma-separated list of ciphers such as `TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384`. The order should be in terms of preference, with the preferred algorithms listed first. (Note that the client cannot specifically choose the algorithm is picked because it is the server that chooses. The client simply provides the server with a list from which to choose.)

The property can also disallow connections with servers having certificates with RSA keys less than a certain size. By default, server certificates having RSA keys of 512 bits or greater are allowed. Add the keyword `rsa1024` to disallow connections with servers having keys smaller than 1024 bits. Add the keyword `rsa2048` to disallow connections with servers having keys smaller than 2048 bits.

**Note:** Prior to Chilkat v9.5.0.55, it was not possible to explicitly list allowed cipher suites. The deprecated means for indicating allowed ciphers was both incomplete and unprecise. For example, the following keywords could be listed to allow matching ciphers: `aes256-cbc`, `aes128-cbc`, `3des-cbc`, and `rc4`. These keywords will still be recognized, but programs should be updated to explicitly list the allowed ciphers.

**secure-renegotiation:** Starting in Chilkat v9.5.0.55, the keyword `secure-renegotiation` may be added to require that all renegotions be done securely (as per RFC 5746).

**best-practices:** Starting in Chilkat v9.5.0.55, this property may be set to the single keyword `best-practices`. This will allow ciphers based on the current best practices. As new versions of Chilkat are released, the best practices may change. Changes will be noted here. The current best practices are:

- If the server uses an RSA key, it must be 1024 bits or greater.
- All renegotations must be secure renegotiations.
- All ciphers using RC4, DES, or 3DES are disallowed.

**Example:** The following string would restrict to 2 specific cipher suites, require RSA keys to be 1024 bits or greater, and require secure renegotiations: `TLS_DHE_RSA_WITH_AES_256_CBC_SHA256, TLS_RSA_WITH_AES_256_CBC_SHA, rsa1024, secure-renegotiation`

### Upload.SslProtocol

`Chilkat 11.7.0 · csharp · Upload · SslProtocol · property · read/write · since 9.5.0.55`

```csharp
public string SslProtocol {get; set; }
```

Selects the secure protocol to be used for secure (SSL/TLS) connections. Possible values are:

> default  
> TLS 1.3  
> TLS 1.2  
> TLS 1.1  
> TLS 1.0  
> SSL 3.0  
> TLS 1.3 or higher  
> TLS 1.2 or higher  
> TLS 1.1 or higher  
> TLS 1.0 or higher

The default value is `default` which will choose the, which allows for the protocol to be selected dynamically at runtime based on the requirements of the server. Choosing an exact protocol will cause the connection to fail unless that exact protocol is negotiated. It is better to choose `X or higher` than an exact protocol. The `default` is effectively `SSL 3.0 or higher`.

### Upload.TlsPinSet

`Chilkat 11.7.0 · csharp · Upload · TlsPinSet · property · read/write · since 9.5.0.55`

```csharp
public string TlsPinSet {get; set; }
```

**Full documentation for this property (same in every language):** [Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md)

Specifies a set of pins for Public Key Pinning for TLS connections. This property lists the expected SPKI fingerprints for the server certificates. If the server's certificate (sent during the TLS handshake) does not match any of the SPKI fingerprints, then the TLS handshake is aborted and the connection fails. The format of this string property is as follows:

```
hash_algorithm, encoding, SPKI_fingerprint_1, SPKI_fingerprint_2, ...
```

For example, the following string specifies a single sha256 base64-encoded SPKI fingerprint:

```
"sha256, base64, lKg1SIqyhPSK19tlPbjl8s02yChsVTDklQpkMCHvsTE="
```

This example specifies two SPKI fingerprints:

```
"sha256, base64, 4t37LpnGmrMEAG8HEz9yIrnvJV2euVRwCLb9EH5WZyI=, 68b0G5iqMvWVWvUCjMuhLEyekM5729PadtnU5tdXZKs="
```

Any of the following hash algorithms are allowed:.sha1, sha256, sha384, sha512, md2, md5, haval, ripemd128, ripemd160,ripemd256, or ripemd320.

The following encodings are allowed: base64, hex, and any of the encodings indicated in the link below.

### Upload.TotalUploadSize

`Chilkat 11.7.0 · csharp · Upload · TotalUploadSize · property · read-only`

```csharp
public uint TotalUploadSize {get; }
```

The total size of the upload (in bytes). This property will become set at the beginning of an asynchronous upload. A program may monitor asynchronous uploads by tracking both NumBytesSent and PercentUploaded.

desc> This property is also set during synchronous uploads.

### Upload.UploadInProgress

`Chilkat 11.7.0 · csharp · Upload · UploadInProgress · property · read-only`

```csharp
public bool UploadInProgress {get; }
```

Set to `true` when an asynchronous upload is started. When the asynchronous upload is complete, this property becomes equal to `false`. A program will typically begin an asynchronous upload by calling BeginUpload, and then periodically checking the value of this property to determine when the upload is complete.

### Upload.UploadSuccess

`Chilkat 11.7.0 · csharp · Upload · UploadSuccess · property · read-only`

```csharp
public bool UploadSuccess {get; }
```

Set to `true` (success) or `false` (failed) after an asynchronous upload completes or aborts due to failure. When a program does an asynchronous upload, it will wait until UploadInProgress becomes `false`. It will then check the value of this property to determine if the upload was successful or not.

## Methods

### Upload.AbortUpload

`Chilkat 11.7.0 · csharp · Upload · AbortUpload · method`

```csharp
public void AbortUpload();
```

May be called during an asynchronous upload to abort.

### Upload.AddCustomHeader

`Chilkat 11.7.0 · csharp · Upload · AddCustomHeader · method`

```csharp
public void AddCustomHeader(string name, string value);
```

Adds a custom HTTP header to the HTTP upload.

### Upload.AddFileReference

`Chilkat 11.7.0 · csharp · Upload · AddFileReference · method`

```csharp
public void AddFileReference(string name, string filename);
```

Adds a file to the list of files to be uploaded in the next call to BlockingUpload, BeginUpload, or UploadToMemory. To upload more than one file, call this method once for each file to be uploaded.

### Upload.AddParam

`Chilkat 11.7.0 · csharp · Upload · AddParam · method`

```csharp
public void AddParam(string name, string value);
```

Adds a custom HTTP request parameter to the upload.

### Upload.BeginUpload

`Chilkat 11.7.0 · csharp · Upload · BeginUpload · method`

```csharp
public bool BeginUpload();
```

Starts an asynchronous upload. Only one asynchronous upload may be in progress at a time. To achieve multiple asynchronous uploads, use multiple instances of the Chilkat Upload object. Each object instance is capable of managing a single asynchronous upload.

desc> When this method is called, a background thread is started and the asynchronous upload runs in the background. The upload may be aborted at any time by calling AbortUpload. The upload is completed (or failed) when UploadInProgress becomes `false`. At that point, the UploadSuccess property may be checked to determine success (`true`) or failure (`false`).

Returns true for success, false for failure.

See also:

- [Debugging HTTP Upload](http://www.cknotes.com/?p=138)
- [HTTP Upload with Progress Monitoring Events](https://www.chilkatsoft.com/p/p_200.asp)

### Upload.BlockingUpload

`Chilkat 11.7.0 · csharp · Upload · BlockingUpload · method`

```csharp
public bool BlockingUpload();
```

Uploads files to a web server using HTTP. The files to be uploaded are indicated by calling AddFileReference once for each file (prior to calling this method).

Returns true for success, false for failure.

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

See also:

- [Debugging HTTP Upload](http://www.cknotes.com/?p=138)
- [IIS 7.0 Upload Size Limitations](http://www.cknotes.com/?p=100)
- [IIS 6.0 Upload Size Limitations](http://www.cknotes.com/?p=136)

### Upload.ClearFileReferences

`Chilkat 11.7.0 · csharp · Upload · ClearFileReferences · method`

```csharp
public void ClearFileReferences();
```

Clears the internal list of files created by calls to AddFileReference.

### Upload.ClearParams

`Chilkat 11.7.0 · csharp · Upload · ClearParams · method`

```csharp
public void ClearParams();
```

Clears the internal list of params created by calls to AddParam.

### Upload.LoadTaskCaller

`Chilkat 11.7.0 · csharp · Upload · 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.

### Upload.SleepMs

`Chilkat 11.7.0 · csharp · Upload · SleepMs · method`

```csharp
public void SleepMs(int millisec);
```

A convenience method for putting the calling process to sleep for N milliseconds. It is provided here because some programming languages do not provide this capability, and sleeping for short increments of time is helpful when doing asynchronous uploads.

### Upload.UploadToMemory

`Chilkat 11.7.0 · csharp · Upload · UploadToMemory · method`

```csharp
public byte[] UploadToMemory();
```

Writes the complete HTTP POST to memory. The POST contains the HTTP header, any custom params added by calling AddParam, and each file to be uploaded. This is helpful in debugging. It allows you to see the exact HTTP POST sent to the server if BlockingUpload or BeginUpload is called.

Returns an empty byte array on failure

## Events and callbacks

### Upload.AbortCheck (event)

`Chilkat 11.7.0 · csharp · Upload · 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 upload_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Upload upload = new Chilkat.Upload();
upload.OnAbortCheck += upload_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.Upload upload = new Chilkat.Upload();
// ...
Chilkat.Upload.AbortCheck abortCheck = new Chilkat.Upload.AbortCheck(handleAbortCheck);
upload.setAbortCheckCb(abortCheck);
```

### Upload.PercentDone (event)

`Chilkat 11.7.0 · csharp · Upload · 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 upload_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Upload upload = new Chilkat.Upload();
upload.OnPercentDone += upload_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.Upload upload = new Chilkat.Upload();
// ...
Chilkat.Upload.PercentDone percentDone = new Chilkat.Upload.PercentDone(handlePercentDone);
upload.setPercentDoneCb(percentDone);
```

### Upload.ProgressInfo (event)

`Chilkat 11.7.0 · csharp · Upload · 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 upload_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Upload upload = new Chilkat.Upload();
upload.OnProgressInfo += upload_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.Upload upload = new Chilkat.Upload();
// ...
Chilkat.Upload.ProgressInfo progressInfo = new Chilkat.Upload.ProgressInfo(handleProgressInfo);
upload.setProgressInfoCb(progressInfo);
```

### Upload.TaskCompleted (event)

`Chilkat 11.7.0 · csharp · Upload · 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 upload_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Upload upload = new Chilkat.Upload();
upload.OnTaskCompleted += upload_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.Upload upload = new Chilkat.Upload();
// ...
Chilkat.Upload.TaskIdCompleted taskIdCompleted = new Chilkat.Upload.TaskIdCompleted(handleTaskIdCompleted);
upload.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 BlockingUploadAsync();
```

## Related classes

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