ASP.NET Code 39 Generator Library SDK

Streaming Code 39 Image into Your ASP.NET Web Pages

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• Under downloaded trial package, copy barcode folder and its contents to your IIS, and create a new virtual directory, named "barcode".
• Restart IIS, navigate to http://YourDomain:Port/barcode/linear.aspx?DATA=CODE39&TYPE=4.
• To create barcode image in html or aspx pages, you can insert a image tag (img) into your web pages.
  For example, <img src="http://YourDomain:Port/barcode/linear.aspx?DATA=CODE39&TYPE=4" />

Generate Code 39 into Your ASP.NET Web Forms

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1. Install ASP.NET Barcode Generator Control.
2. Add ASP.NET Barcode Generator Control to your Visual Studio Toolbox.
3. Copy "linear.aspx" and "linear.aspx.cs" to the folder where your aspx pages are generating barcodes.
4. Drag and drop "LinearWebForm" to your ASPX web forms.
5. Run the website to view the barcodes generated. To customize Code 39 settings, view Code 39 barcode settings.

Generate Code 39 Barcodes in ASP.NET Class

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Code 39 Standard Mode

Standard Code 39 supports 43 fixed characters for general use.

Set Type = BarcodeType.CODE39 to enable this mode.

Supported characters:

• Numeric digits: 0 - 9
• Uppercase letters: A - Z
• Special characters: -, $, %, (Space), ., /, +
• Automatic Start/Stop characters (*)

Code 39 Full ASCII Mode (CODE39EX)

Code 39 Full ASCII (Extended) supports the complete 128-character ASCII set (ISO 646 IRV).

Set Type = BarcodeType.CODE39EX to enable lowercase letters and special symbols.



Note: Always use CODE39EX for lowercase text in ASP.NET applications. Standard mode will fail to encode lowercase characters.

Code 39 Check Digit (MOD43)

Code 39 does not include a check digit by default.

For enhanced data security, enable MOD43 checksum using AddCheckSum = true.

Hide Check Digit in HRI (Human Readable Interpretation)

You can enable the check digit but hide it from the displayed text.

Set ShowCheckSumChar = false.

Show / Hide Start/Stop Characters (*)

Code 39 uses * as Start and Stop symbols.

Control visibility with ShowStartStopInText.

Customize barcode size for your ASP.NET View, Partial View, or printing requirements.

All properties are configured in the Request Pipeline before image generation.

• UOM: Unit of measure (PIXEL, CM, INCH)
• X: Width of the narrow bar module
• Y: Height of the barcode module
• N: Wide-to-narrow bar ratio (2.0 - 3.0)
• I: Intercharacter gap width (multiple of X)
• LeftMargin / RightMargin: Quiet zone (minimum 10X)

Note: The minimum quiet zone is 10X. Smaller margins will cause scanning failures in production environments.

Wide Bar vs Narrow Bar Ratio (Property N)

The N property defines the width ratio between wide and narrow bars.

Valid range: 2.0 to 3.0 (default = 2).

Intercharacter Gap (Property I)

The I property sets the space between barcode characters.

It is a multiple of the narrow module width X (default = 1.0f).

You have learned the complete process to generate and customize Code 39 barcodes in ASP.NET projects using C#.

Key content covered:

• Two encoding modes: Standard (uppercase only) and Full ASCII (all characters)
• Check digit (MOD43) and text display settings improve security and usability
• Full control over dimensions, margins, and module sizes for web and print
• Advanced ratio and spacing adjustments ensure high scanning compatibility
• Fully supports ASP.NET Core, MVC, Razor Pages, Web API, and IIS/Kestrel hosting

You can now deploy robust Code 39 barcode functionality into any ASP.NET web application.