Introduction

.netCHARTING label strings can be used as dynamic templates capable of evaluating mathematical expressions, embedding info about the associated object, and specifying format strings. They can also include layout and embedded font styling information and links. Images can be used inside labels mixed in with text and dynamic streaming charts generated by aspx pages among other features.

Label is a very powerful object that includes a great deal of functionality. This is an overview list of label related features:

The following diagram demonstrates the properties used to access different labels. 

Chart Labels Diagram

 

Click on any property name for additional information.

Handling Oversized Labels

The axis tick labels use very advanced algorithms to display labels and provide automatic label wrapping, however, not all labels wrap automatically. There are two ways to remedy issues when long labels are becoming a problem. One way to deal with this is to use label truncation. This feature is accessed through the Label.Truncation property. This feature allows limiting the label text to a specified number of characters.

See sample LabelTruncation.aspx for more info.

Most labels will allow automatic wrapping where the label will dynamically determine when and where to wrap text. This feature must be turned on as shown below:

[C#]
Chart.DefaultElement.SmartLabel.AutoWrap = true;

[Visual Basic]
Chart.DefaultElement.SmartLabel.AutoWrap = True

Samples: AutoWrapLabels.aspx PieLabelSmartWrapping.aspx

Labels that dont support automatic wrapping can also be wrapped, however, this must be done manually and is achieved by inserting a new line character into the text of the label.

Tokens

Tokens can be used to embed information about the object associated with the label. For example the label of an element can contain the '%Name' token. When parsed, the token will evaluate to the element's name. The Label Token Reference lists objects and the tokens that are available for each.

Sample: ElementTemplate.aspx

Expressions

Mathematical expressions can also be evaluated within label strings. An expression must be encapsulated within '<' and '>' characters, similar to an xml tag. An example of a simple expression is '<2+2>' which would result in '4' in the final label text. If this expression string is intended to be taken literally, a preceding '\' character will prevent the expression parser from evaluating it. For example the string '\<2+2>' would result in '<2+2>'. Expressions can group parts of the expression using parentheses: (). Example:  <(5+5)*3>. Expressions can also include tokens as values, for example: <%YValue/3>

Expression Functions

Besides simple expressions, labels can evaluate advanced functions such as sin, cos, or sqrt.

[C#]

Chart.DefaultElement.SmartLabel.Text = "<%YValue+sin(%YValue)>";

[Visual Basic]

Chart.DefaultElement.SmartLabel.Text = "<%YValue+sin(%YValue)>"

This table lists the available functions.

Embedded Format Strings (In-Line Formatting)

Values can be formatted in-line within the label using the above syntax.

For more information on in-line formatting see the Advanced Formatting tutorial.

Token, Expressions, and In-Line Formatting Examples

The following examples will demonstrate tokens, expressions, and embedded format strings usage.