The LED control is an ActiveX custom control that implements the functionality of a single 7-segment LED-style digit, which is the type found in many calculators and other handheld devices.

The following table documents the LED control's properties, methods, and events in an interactive manner: you can experiment with the control "live", so long as are using Internet Explorer and the control is properly installed. This page attempts to install the control; however, modern versions of Internet Explorer (quite correctly) refuse to install components of unknown origin, so your best bet is to download the control DLL and then, as Administrator, run regsvr32 LED.dll from the command console.

In any case, feel free to examine the source code of this page to learn more about the control's operation.

Please go to the bottom of the page for purchase information.

Stock Properties

Appearance Bit map property indicating segment states. The lower seven bits are used to set segments A-G. Bit 7 sets the decimal point. To have the Appearance property override the Caption property, combine these values with 0x8000 (i.e., use a negative value).
BackColor The color of the digit's background area. An RGB value, computed as B*65536+G*256+R. Black is 0, white is 16777215.
BorderColor The color used to draw the segment outlines.
Caption The digit to be displayed. Single-character string that may be any character between "0" and "9", or the "-" character. May also be a two-character string; in this case, the presence of a decimal point in the second position indicates that the decimal point should appear "lit".
FillColor The color used to fill the interior of unlit segments.
ForeColor The color used to fill the interior of lit segments.

To download the LED control DLL to your computer, right click on this link and select "Save Target As..." from the context menu. Note that the downloaded DLL is of little use by itself; you must also purchase a license.

The LED control DLL cannot be used in your own projects, or redistributed to end-users without a license. You can purchase a license online. When you purchase a single developer or site license, your license information will be e-mail to you automatically. When you purchase an unrestricted license, your purchase will be reviewed, and a full source archive will be e-mailed to you, usually within 24 hours of your purchase.

License type

Price in USD

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Single Developer License
Authorizes a single developer to use the control in his or her projects, and redistribute the control to end-users. No source code is included.

Site License
Authorizes a group of developers working together at the same geographic location to use the control in their projects, and redistribute the control to end-users. No source code is included.

Unrestricted License
Provides a non-exclusive license to do as you please with the control. Includes the license to modify the control, redistribute the control in source or object form, or incorporate the control or any parts thereof into your projects. Source code included.