Requirements and restrictions on Expressions

Requirements and restrictions on Expressions

The BizTalk expression editor in the Business Process designer is a standard Visual Studio text editor, which means it provides the intelliisense function. You can use the BizTalk expression editor to enter an expression in text format.

You can enter a single expression in the text box. The expression can span multiple rows, but must end with a semicolon.

The following lists the restrictions that must be observed when using expressions in the BizTalk expression Editor:

• compound assignment is not supported, such as "+ =", "-=", or "* = ".

• multiple value assignment operators cannot be used in one statement.
• values cannot be assigned in the "if" or "while" predicates.
• increment and decrease are not supported. For example, "++" and "--".
• for the message section, use Microsoft. xlangs. basetypes. distinguishedfieldattribute, all public data fields and non-read-only fields.. NET attributes can be annotated with public methods, nested types, static data fields, read-only.. net.
• indexer or parameterized. NET attributes are not supported.
• delegation and events are not supported.
• generics are not supported.
• the stream control syntax is not supported, such as "foreach", "for", "do-while", "break", and "continue ".
• ternary computation is not supported. For example, :".
• you can add comments to the expression shape, but the expression shape must contain at least one statement.
• arrays are not supported.
• when you place an expression shape in a message shape, you cannot execute any control flow. For example, "If-then-else" or "while ".
• all valid expression statements are in the following format:
• dotted-name = expression;
• Dotted-name.FunctionCallExpression;

although you can use the BizTalk expression editor to easily and quickly enter complex expressions, you cannot use it to enter any number of codes . This is to make the business process code different from its implementation code.