MIME Control

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The MIME control allows for the simple encoding and decoding of MIME structures, such as message attachments and file uploads.

Syntax

MIME

Remarks

The control may be used for decoding or encoding of messages. Message holds the content of the encoded message or the filename that holds the encoded data. The decoded data are provided in Parts properties.

To decode a MIME message, you should first assign either the whole message (headers and body) to Message or put the message headers into the MessageHeaders property and the message body or the filename holding it into the Message property. Calling DecodeFromFile or DecodeFromString directs the control to start parsing the message: it will fill out the ContentType and ContentTypeAttr properties with message content-type information, and it will enter information about message parts into the Parts properties, which includes part sizes, part content types, part content type attributes, part content disposition, part content disposition attributes, part encoding, part name, part filename, part headers, or part content (part-decoded string or part-decoded file) for each decoded part.

Calling the DecodeFromString or DecodeFromFile to decode does not actually decode the message but only parses it. The real decoding is done when the part content in the Parts properties is first accessed.

To encode data into a MIME message, you should first assign values for each part to either a part-decoded string or a part- decoded file in the Parts properties property, and optionally assign values to the other part attributes in the Parts properties. Assigning a value to the part-decoded string or a part-decoded file through the Parts properties, fills out automatically the part headers into the Parts properties for the respective part. Calling EncodeToFile or EncodeToString directs the control to fill out the Message with the message body and the MessageHeaders with the headers.

The Progress event is fired as the message is parsed and the data are decoded/encoded.

Property List

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The following is the full list of the properties of the control with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the control with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the control with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the control with short descriptions. Click on the links for further details.

Boundary Property (MIME Control)

This property includes the boundary separating the MIME parts. It has a maximum length of 80 bytes.

Syntax

mimecontrol.Boundary[=string]

Default Value

""

Remarks

This property contains the boundary separating the MIME parts and has a maximum length of 80 bytes. The control automatically generates a random boundary value during encoding, if no value is given. During decoding, this property is filled with the boundary from the actual MIME message.

The control will truncate any string longer than 80 bytes if assigned to Boundary.

Data Type

String

ContentType Property (MIME Control)

This property includes the value of the content-type header of the message that was encoded/decoded.

Syntax

mimecontrol.ContentType[=string]

Default Value

""

Remarks

This property contains the value of the content-type header of the message that was encoded/decoded. The control filters it out from the MessageHeaders. It shows the user information about the type of the parts and their relation to each other.

The content-type attributes, such as filename, boundary, and charset, are held in this property.

Data Type

String

ContentTypeAttr Property (MIME Control)

This property includes the attributes of the content-type header of the message that was encoded or decoded.

Syntax

mimecontrol.ContentTypeAttr[=string]

Default Value

""

Remarks

This property contains content-type attributes such as "filename", "boundary", and "charset".

Data Type

String

Message Property (MIME Control)

This property contains the encoded message text or a path to a file that contains the encoded message text.

Syntax

mimecontrol.Message[=string]

Default Value

""

Remarks

This property contains the encoded message text or a path to a file that contains the encoded message text. The control fills out this property with the message body and MessageHeaders during encoding. The user may assign both the headers and the body to this property and leave MessageHeaders empty before decoding.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .MessageB.

This property is not available at design time.

Data Type

Binary String

MessageHeaderCount Property (MIME Control)

The number of records in the MessageHeader arrays.

Syntax

mimecontrol.MessageHeaderCount[=integer]

Default Value

0

Remarks

This property controls the size of the following arrays:

• MessageHeaderField
• MessageHeaderValue

The array indices start at 0 and end at MessageHeaderCount - 1.

This property is not available at design time.

Data Type

Integer

MessageHeaderField Property (MIME Control)

This property contains the name of the HTTP header (this is the same case as it is delivered).

Syntax

mimecontrol.MessageHeaderField(MessageHeaderIndex)[=string]

Default Value

""

Remarks

This property contains the name of the HTTP Header (this is the same case as it is delivered).

The MessageHeaderIndex parameter specifies the index of the item in the array. The size of the array is controlled by the MessageHeaderCount property.

This property is not available at design time.

Data Type

String

MessageHeaderValue Property (MIME Control)

This property contains the header contents.

Syntax

mimecontrol.MessageHeaderValue(MessageHeaderIndex)[=string]

Default Value

""

Remarks

This property contains the Header contents.

The MessageHeaderIndex parameter specifies the index of the item in the array. The size of the array is controlled by the MessageHeaderCount property.

This property is not available at design time.

Data Type

String

MessageHeadersString Property (MIME Control)

This property includes the string version of the MIME message headers.

Syntax

mimecontrol.MessageHeadersString[=string]

Default Value

""

Remarks

The component fills out MessageHeadersString upon encoding. The user should use these strings as additional headers when emailing the Message.

This property contains a string version of the MIME message headers. During decoding, if this property is empty, the control will try to find the headers in the beginning of the Message and will fill out this property accordingly.

Data Type

String

PartCount Property (MIME Control)

The number of records in the Part arrays.

Syntax

mimecontrol.PartCount[=integer]

Default Value

0

Remarks

This property controls the size of the following arrays:

• PartContentDisposition
• PartContentDispositionAttr
• PartContentId
• PartContentType
• PartContentTypeAttr
• PartDecodedFile
• PartDecodedString
• PartEncoding
• PartFilename
• PartHeaders
• PartName
• PartSize

The array indices start at 0 and end at PartCount - 1.

This property is not available at design time.

Data Type

Integer

PartContentDisposition Property (MIME Control)

This property contains content disposition for each part.

Syntax

mimecontrol.PartContentDisposition(PartIdx)[=string]

Default Value

""

Remarks

This property contains content disposition for each part.

The value in this property is used in the Content-Disposition header. Typical values include "form-data" and "attachment". The control fills it out each time the PartDecodedFile is changed. Changing the PartContentDisposition recalculates the PartHeaders as well.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartContentDispositionAttr Property (MIME Control)

This property contains the content disposition's attribute (if any) for each part.

Syntax

mimecontrol.PartContentDispositionAttr(PartIdx)[=string]

Default Value

""

Remarks

This property contains the content disposition's attribute (if any) for each part.

Typical values for this property are the names of the form-variables used while creating an HTTP post or the values for filenames.

Setting this property recalculates the PartHeaders.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartContentId Property (MIME Control)

This property contains the content identifier for each part.

Syntax

mimecontrol.PartContentId(PartIdx)[=string]

Default Value

""

Remarks

This property contains the content identifier for each part. The value of this property is used in the Content-Id header. The control fills it out each time the PartDecodedFile is changed. Changing this property recalculates the PartHeaders as well.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartContentType Property (MIME Control)

This property contains the content type for each part.

Syntax

mimecontrol.PartContentType(PartIdx)[=string]

Default Value

""

Remarks

This property contains the content type for each part. The value of this property is used in the Content-Type header. Typical values include "image/gif" and "text/plain". The control fills it out each time the PartDecodedFile is changed. Changing this property recalculates the PartHeaders as well.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartContentTypeAttr Property (MIME Control)

This property contains the content-type attribute, if any, for each part.

Syntax

mimecontrol.PartContentTypeAttr(PartIdx)[=string]

Default Value

""

Remarks

This property contains the content-type attribute, if any, for each part. Setting this recalculates the PartHeaders as well.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartDecodedFile Property (MIME Control)

This property contains the filename with the decoded data.

Syntax

mimecontrol.PartDecodedFile(PartIdx)[=string]

Default Value

""

Remarks

This property contains the filename with the decoded data. Accessing this property for the first time after calling the DecodeFromString or DecodeFromFile method, directs the control to actually decode the part and save the data in a temporary file. The user is responsible for deleting the temporary file.

Setting a value to PartDecodedFile directs the component to calculate the file size and fill out the respective PartSize.

Note: It is recommended to use the DecodePartToFile method instead of querying this property.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartDecodedString Property (MIME Control)

This property holds the actual content of each part.

Syntax

mimecontrol.PartDecodedString(PartIdx)[=string]

Default Value

""

Remarks

This property holds the actual content of each part. The control decodes the actual part of Message to PartDecodedString when PartDecodedString's value is first queried.

Setting a value to PartDecodedString fills out the corresponding PartSize with the string size if the corresponding PartDecodedFile is empty.

The control checks during encoding first PartDecodedFile: if it is empty, then the control uses the value of PartDecodedString.

Note: It is recommended to use the DecodePart method instead of querying this property.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .PartDecodedStringB.

This property is not available at design time.

Data Type

Binary String

PartEncoding Property (MIME Control)

This property contains the actual content encoding type for each part.

Syntax

mimecontrol.PartEncoding(PartIdx)[=integer]

Possible Values

pe7Bit(0), 
peQuotedPrintable(1), 
peBase64(2), 
pe8Bit(3), 
peBinary(4), 
peUUEncode(5)

Default Value

0

Remarks

This property contains the actual content encoding type for each part. This property determines how to encode the data or how they actually were encoded in the Message, as specified in the Content-Transfer-Encoding header.

Possible values for the this property are as follows:

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

Integer

PartFilename Property (MIME Control)

This property contains the filename attribute specified in the headers of the part.

Syntax

mimecontrol.PartFilename(PartIdx)[=string]

Default Value

""

Remarks

This property contains the filename attribute specified in the headers of the part. Changing the value of the corresponding PartDecodedFile automatically sets the PartFilename and consequently the PartHeaders.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartHeaders Property (MIME Control)

This property contains the headers for each MIME part.

Syntax

mimecontrol.PartHeaders(PartIdx)[=string]

Default Value

""

Remarks

This property contains the headers for each MIME part. The control fills out this property each time any of the other corresponding part properties are changed. If additional headers are needed, they should be appended after all of the other corresponding part properties are set.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartName Property (MIME Control)

This property contains the name given to a part, such as the filename.

Syntax

mimecontrol.PartName(PartIdx)[=string]

Default Value

""

Remarks

This property contains the name given to a part, such as the filename. Changing the value of PartDecodedFile automatically sets the corresponding PartName and consequently the PartHeaders.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is not available at design time.

Data Type

String

PartSize Property (MIME Control)

This property contains the size of the DecodedFile or DecodedString .

Syntax

mimecontrol.PartSize(PartIdx)

Default Value

0

Remarks

This property contains the size of the PartDecodedFile or PartDecodedString. If a non-empty value is assigned to PartDecodedFile, then control fills out the corresponding PartSize with the file size; if the file does not exist, an error occurs.

If the PartDecodedFile is empty and a value is assigned to PartDecodedString, then the corresponding PartSize will be equal to the string's size.

During decoding, this property is filled with the size of that part.

The PartIdx parameter specifies the index of the item in the array. The size of the array is controlled by the PartCount property.

This property is read-only and not available at design time.

Data Type

Integer

Config Method (MIME Control)

Sets or retrieves a configuration setting.

Syntax

mimecontrol.Config ConfigurationString

Remarks

Config is a generic method available in every control. It is used to set and retrieve configuration settings for the control.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DecodeFromFile Method (MIME Control)

This method decodes from a file.

Syntax

mimecontrol.DecodeFromFile 

Remarks

This method decodes the data file given in Message and optionally MessageHeaders and fills out the Parts properties for each decoded part.

Example. Decoding from a File:

MIMEControl.Message = "C:\filename.txt" MIMEControl.DecodeFromFile

In this example, C:\filename.txt must contain the MIME headers and body. If not, the MessageHeaders property must be set to the appropriate MIME headers.

DecodeFromString Method (MIME Control)

This method decodes from a string.

Syntax

mimecontrol.DecodeFromString 

Remarks

This method decodes from a string. It is the same as DecodeFromFile, but now the Message denotes the real encoded message rather than a filename.

This method decodes the data given in Message and optionally MessageHeaders and fills out the Parts properties.

Example. Decoding a Mail Message:

MIMEControl.MessageHeadersString = MailControl.MessageHeaders MIMEControl.Message = MailControl.MessageText MIMEControl.DecodeFromString

DecodePart Method (MIME Control)

This method decodes the specified part.

Syntax

mimecontrol.DecodePart index

Remarks

This method decodes the part specified by Index and returns the decoded part data.

DecodeFromString or DecodeFromFile must be called before calling this method. Calling this method will return the decoded bytes, and in addition, the PartDecodedString property will be populated with the string representation of the decoded data.

Example. Decoding a Specified Part:mime.MessageHeadersString = myMessageHeaders; mime.Message = myMessageBody; mime.DecodeFromString(); byte[] myPartContent = await mime.DecodePart(0);

DecodePartToFile Method (MIME Control)

This method decodes the specified part to a file on disk.

Syntax

mimecontrol.DecodePartToFile index

Remarks

This method decodes the part specified by Index to a temporary file. The full path to the temporary file is returned by this method. The user is responsible for deleting the temporary file.

DecodeFromString or DecodeFromFile must be called before calling this method.

EncodeToFile Method (MIME Control)

This method encodes to a file.

Syntax

mimecontrol.EncodeToFile 

Remarks

This method encodes the data given in Parts properties (either a decoded file or a decoded string) into a MIME message at Message and MessageHeaders using the values optionally given in Parts properties. To encode several objects into a MIME envelope, the user should first clear any old values left in the Parts properties.

The control will check for each item in Parts properties (first the decoded file and then the decoded string) for the data to encode.

The encoded message will be saved in the file pointed to by Message; the message headers will be held by MessageHeaders.

Example. Encoding Data:

MIMEControl.ResetData() MIMEControl.PartCount = 2 MIMEControl.PartDecodedString(0) = "This is plain text data" MIMEControl.PartEncoding(0) = peQuotedPrintable MIMEControl.PartContentType(0) = "text/plain" MIMEControl.PartDecodedFile(1) = "C:\filename.txt" MIMEControl.Message = "temp.tmp" MIMEControl.EncodeToFile()

EncodeToString Method (MIME Control)

This method encodes to a string.

Syntax

mimecontrol.EncodeToString 

Remarks

This method encodes to a string. It is the same as EncodeToFile but the encoded data are held in the Message property rather than saved to a file.

This method encodes the data given in the Parts properties into a MIME message. The message gets stored in Message and MessageHeaders using the values optionally given in Parts properties. To encode several objects into a MIME envelope, the user should first clear any old values left in the Parts properties by calling ResetData.

The control will check each item in the Parts properties (first the decoded file and then the decoded string) for the data to encode.

The encoded message will be stored in the Message property; the message headers will be held by MessageHeaders.

Example. Encoding Data:

MIMEControl.ResetData() MIMEControl.PartCount = 2 MIMEControl.PartDecodedString(0) = "This is plain text data" MIMEControl.PartEncoding(0) = peQuotedPrintable MIMEControl.PartContentType(0) = "text/plain" MIMEControl.PartDecodedFile(1) = "C:\filename.txt" MIMEControl.EncodeToString()

Reset Method (MIME Control)

Reset the control.

Syntax

mimecontrol.Reset 

Remarks

This method will reset the control's properties to their default values.

ResetData Method (MIME Control)

This method resets the values of all headers and part properties.

Syntax

mimecontrol.ResetData 

Remarks

This method resets the values of all headers and part properties. It is an easy way to reset the control's properties before starting to populate the part properties with new values.

Error Event (MIME Control)

Information about errors during data delivery.

Syntax

Sub mimecontrol_Error(ErrorCode As Integer, Description As String)

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the control fails with an error.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Header Event (MIME Control)

This event is fired every time a header is parsed.

Syntax

Sub mimecontrol_Header(PartIndex As Integer, Field As String, Value As String)

Remarks

The PartIndex parameter contains the index of the part containing the current header. If the header is from the MIME body, this value will be -1. The Field parameter contains the name of the MIME header. The Value parameter contains the header contents. The Header event is fired when a header is parsed, which occurs for each header of the message when DecodeFromFile, DecodeFromString, or DecodeFromStream is called.

Progress Event (MIME Control)

This event shows the progress of decoding or encoding the input data.

Syntax

Sub mimecontrol_Progress(PercentDone As Integer)

Remarks

The Progress allows the user to visualize the progress of processing the input data.

The PercentDone parameter shows what percentage of the input has been read.

Config Settings (MIME Control)

The control accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, access to these internal properties is provided through the Config method.

MIME Config Settings

Base Config Settings

Trappable Errors (MIME Control)

MIME Errors

	20004    Can't create the file for write (illegal name or disk is write-protected).
	20005    Can't open the file for read (doesn't exist?).
	20006    Can't read from file.
	20007    Can't write to file (disk full?).
	20281    Invalid Part Index.
	20282    Unknown MIME type.
	20283    No MIME-boundary found.
	20284    No file given.
	20285    The control is busy.
	20286    Can't create a temporary file to decode the data.
	20287    Can't read Message file.
	20288    No header separator found.
	20290    No separator found.
	20291    Input stream must have seeking enabled.