Visual Guard Expression Language

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Note
Visual Guard expression language is available only when the version 2.7 (or higher) of Visual Guard assemblies are referenced in your application.

Operators	Description	Example
==	equality	0 == 0
!=	inequality	1 != 0
>	greater than	1 > 0
>=	greater than or equal	1 >= 1
<	less than	0 < 1
<=	less than or equal	1 <= 1
is	checks if an object is compatible with a given type	‘1’ is string
like	compares a string against a pattern	‘Abc’ like ‘[A-Z]b*’
between	checks if a numeric or string value is between two values	1 between {0,2} ‘efg’ between {‘abc’, ‘xyz’}
matches	checks if a string value matches a regular expression	‘5.00’ matches ‘^-?\d+(\.\d{2})?$’
=	Assignment (not available in condition)	myValue = 1
and	logical or conditional AND operator (compatible with integer, enum or boolean types)	1 == 1 and ‘a’ == ‘a’ MyEnum.Value1 and MyEnum.Value2 1 and 2
or	logical or conditional OR operator (compatible with integer, enum or boolean types)	1 == 1 or ‘a’ == ‘b’ MyEnum.Value1 or MyEnum.Value2 1 or 2
!	logical negation operator (compatible with integer, enum or boolean types)	!true !1 !MyEnum.Value1
? :	ternary operator. returns the value of the first expression if the condition is true, otherwise return the value of the second expression.	1 == 1?’abc’:’def’
??	?? operator returns the left-hand operand if it is not null, or else it returns the right operand.	MyStringValue??’def’
+	computes the sum of 2 operands (compatible with number, string or datetime types)	1 + 1 ‘abc’ + ‘efg’ date(‘1974-08-24’) + 5
–	subtracts the second operand from the first (compatible with number, datetime types)	1-1 date(‘1974-08-24’) – 5 date(‘2004-08-14’) – date(‘1974-08-24’)
*	computes the product of its operands.	1 * 2
/	divides its first operand by its second	10 / 5
%	computes the remainder after dividing its first operand by its second	5 % 2
^	raises first number to the power of the second one.	2 ^ 5
new	used to create objects and invoke constructors	new System.Collections.ArrayList() new int[] {1,2,3}
null	represents a null (Nothing in VB.Net) reference
T()	Used to obtain the System.Type object for a type	T(System.String) T(System.String, mscorlib) T(MyNamspace.MyClass[], myassembly)
C()	Converts an expression to a specifed type (equivalent to DirectCast in VB.Net or cast operator in C#)	C(Controls[0], T(System.Windows.Forms.Button)) C( _employees[0],T(Sample.Employee))

Language Reference

Literal expressions

myString == 'Hello World' // returns true if myString is equal to "Hello World"
myString == 'Tony''s Pizza' // returns true if myString is equal to "Tony's Pizza"
avogadrosNumber == 6.0221415E+23 // returns true if avogadrosNumber is equal to 6.0221415E+23
maxValue == 0x7FFFFFFF  // returns true if maxValue is equal to 2147483647
myDate == date('1974/08/24') // returns true if myDate is equal to August 24, 1974
myDate == date('19740824T031030', 'yyyyMMddTHHmmss') // returns true if myDate is equal to August 24, 1974 at 03:10:30 AM
myBoolean == true // return tue if myBoolean value is equal to true
nullValue == null // returns true if nullValue is equal to null

Double.Parse

Decimal.Parse

Single.Parse

DateTime.ParseExact

CultureInfo.InvariantCulture

Relational operators

IComparable

2 == 2 // true
date('1974-08-24') != DateTime.Today  // true
2 < -5.0 // false
DateTime.Today <= date('1974-08-24') // false
'Test' >= 'test' // true

3 in {1, 2, 3, 4, 5}  // true
'Abc' like '[A-Z]b*'  // true
'Abc' like '?'  // false
1 between {1, 5}  // true
'efg' between {'abc', 'xyz'}  // true
'xyz' is int  // false
{1, 2, 3, 4, 5} is IList  // true
'5.0067' matches '^-?\\d+(\\.\\d{2})?

Boolean Logical operators

true and false // returns false
true or false  // returns true
true and !true // returns false

Enumeration Logical operators

namespace Sample
{
    [Flags]
    public enum Access
    {
        NoAccess = 0,
        Read = 1,
        Write = 2,
        Create = 4,
        ReadWrite = Read | Write,
        AllAccess = ReadWrite | Create
    }
}

Sample.AllAccess and Sample.Write // Returns Sample.Write
Sample.Read or Sample.Write // Returns Sample.ReadWrite
Sample.AllAccess and !Sample.Create // Returns Sample.ReadWrite

Integer Logical operators

3 and 1 // returns 1
1 or 2 // returns 3
!1 // returns -2 (equivalent to '~1' in c# or 'Not 1' in VB.Net)

Ternary operators

2 > 1?'abc':'def' // returns 'abc'
'a' != 'b'?'abc':'def' // returns 'def'

1 + 1 // 2
'test' + ' ' + 'string' //'test string'
date('1974-08-24') + 5 // 8/29/1974
1 - 3; // -2
1000.00m - 1e4 // 9000.00
date('2004-08-14') - date('1974-08-24') // returns a TimeSpan equals to 10948.00:00:00
-2 * -3 // 6
2.0 * 3e0 * 4 // 24
6 / -3 // -2
8.0 / 4e0 / 2 // 1
7 % 4 // 3
8.0 % 5e0 % 2 // 1
-2 ^ 4 // 16
1+2-3*8^2/2/2 // -45

Types

1 is int // returns true
DateTime.Today // returns a datetime object containing the current date
new string[] {'abc', 'efg'} // returns an array of strings
System.DateTime == date // returns true
date('2004-08-14').GetType() == T(System.DateTime, mscorlib) // returns true

Constructors

new DateTime(1974, 8, 24) // returns a DateTime object equals to the specified date
new System.Collections.ArrayList(new object[]{'a', 1, date('2004-08-14')}) // returns an ArrayList object containing a string, an int and a datetime.
new T(System.Collections.ArrayList, mscorlib)(10) // returns an ArrayList object

Variables

#this is System.Collections.IList // returns true when the object for which the expression is evaluated implements the IList interface

Properties, Arrays, Lists, Dictionaries, Indexers

namespace Sample
{

          public class Employee
          {
                private int _employeeId;
                private string _firstName;
                private string _lastName;
                private Company _company;
                private MaritalStatus _maritalStatus;

                public Employee(Datetime dateOfBirth, string firstName, string lastName)
                {
                        ....
                }
                public int Id
                {
                    get { return _employeeId; }
                }
                public string FirstName
                {
                    get { return _firstName; }
                    set { _firstName = value; }
                }
                public string LastName
                {
                    get { return _lastName; }
                    set { _lastName = value; }
                }
                public Company Company
                {
                    get { return _company; }
                    set { _company = value; }
                }
                public MaritalStatus Status
                {
                    get { return _maritalStatus; }
                    set { _maritalStatus = value; }
                }
                public static Employee[] GetEmployees()
                {
                    ...
                }
            }
            public enum MaritalStatus
            {
                Married,
                Divorsed,
                Single
            }
            public class Company
            {
                private string _name;
                private ArrayList _employees;
                public Company(string name)
                {
                        ....
                }
                public string Name
                {
                    get { return _name; }
                    set { _name = value; }
                }
                public int AddEmployee(Employee employee)
                {
                     ...
                }
                public int RemoveEmployee(Employee employee)
                {
                    ...
                }
                public Employees[] GetEmployees()
                {
                    ...
                }
                public Employee this[int employeeId]
                {
                    ...
                }
            }
        }

Properties and methods

GetEmployees().Length

#this.GetEmployees().Length

#this.Name.StartsWith('A')

#this._employees

_employees.Clear()

Arrays, Lists, Dictionaries, Indexers

#this[1].Name

[1].Name

#this[1].Status == Sample.MaritalStatus.Divorced

GetEmployees().Length > 1000

_employees[0].Name

Note
Since *_employees* is an *ArrayList* object, the values returns by *_employees[0]* is an object. At design time, Visual Guard console generates a warning indicating that the ‘*Name‘ property is not a member of ‘System.Object‘. In our case, we can ignore this warning because we are sure that _employees* variable contains only *Employee* object. If you want to suppress this warning at design time, you use the C() keyword to cast this value to *Employee* type:

C( _employees[0],T(Sample.Employee)).Name

Static (Shared) members

Sample.Employee.GetEmployees().Length

T(Sample.Employee, sampleassembly).GetEmployees().Length

Other Resources

// false '5.00' matches '^-?\d+(\.\d{2})?

Boolean Logical operators

Enumeration Logical operators

Integer Logical operators

Ternary operators

Types

Constructors

Variables

Properties, Arrays, Lists, Dictionaries, Indexers

Properties and methods

Arrays, Lists, Dictionaries, Indexers

Note
Since *_employees* is an *ArrayList* object, the values returns by *_employees[0]* is an object. At design time, Visual Guard console generates a warning indicating that the ‘*Name‘ property is not a member of ‘System.Object‘. In our case, we can ignore this warning because we are sure that _employees* variable contains only *Employee* object. If you want to suppress this warning at design time, you use the C() keyword to cast this value to *Employee* type:

Static (Shared) members

Other Resources

// true

Boolean Logical operators

Enumeration Logical operators

Integer Logical operators

Ternary operators

Types

Constructors

Variables

Properties, Arrays, Lists, Dictionaries, Indexers

Properties and methods

Arrays, Lists, Dictionaries, Indexers

Note
Since *_employees* is an *ArrayList* object, the values returns by *_employees[0]* is an object. At design time, Visual Guard console generates a warning indicating that the ‘*Name‘ property is not a member of ‘System.Object‘. In our case, we can ignore this warning because we are sure that _employees* variable contains only *Employee* object. If you want to suppress this warning at design time, you use the C() keyword to cast this value to *Employee* type:

Static (Shared) members