Class ExpressionFieldDescriptor

ExpressionFieldDescriptor is a FieldDescriptor with support for run-time formula expressions.

Expression fields are managed by the ExpressionFieldDescriptorCollection that is returned by the ExpressionFields property of a TableDescriptor.

Inheritance
System.Object
ShouldSerializeBasedPersisterType
DescriptorBase
FieldDescriptor
ExpressionFieldDescriptor
Implements
System.ComponentModel.ICustomTypeDescriptor
System.IDisposable
System.ICloneable
Inherited Members
System.Object.Equals(System.Object, System.Object)
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Syncfusion.Grouping
Assembly: Syncfusion.Grouping.Base.dll
Syntax
public class ExpressionFieldDescriptor : FieldDescriptor, ICustomTypeDescriptor, IDisposable, ICloneable, IStandardValuesProvider

Constructors

ExpressionFieldDescriptor()

Initializes a new empty instance for ExpressionFieldDescriptor expression field.

Declaration
public ExpressionFieldDescriptor()

ExpressionFieldDescriptor(String)

Initializes a new empty instance for ExpressionFieldDescriptor expression field.

Declaration
public ExpressionFieldDescriptor(string name)
Parameters
Type Name Description
System.String name

The name of the field.

ExpressionFieldDescriptor(String, String)

Initializes a new empty instance for ExpressionFieldDescriptor expression field with a name and expression.

Declaration
public ExpressionFieldDescriptor(string name, string expression)
Parameters
Type Name Description
System.String name

The name of the field.
System.String expression

The expression. See the Grid User's Guide for expression syntax and examples.

ExpressionFieldDescriptor(String, String, String)

Initializes a new empty instance for ExpressionFieldDescriptor expression field a name, expression, and result type.

Declaration
public ExpressionFieldDescriptor(string name, string expression, string resultType)
Parameters
Type Name Description
System.String name

The name of the field.
System.String expression

The expression. See the Grid User's Guide for expression syntax and examples.
System.String resultType

The result type.

ExpressionFieldDescriptor(String, String, Type)

Initializes a new empty instance for ExpressionFieldDescriptor expression field with a name, expression, and result type.

Declaration
public ExpressionFieldDescriptor(string name, string expression, Type resultType)
Parameters
Type Name Description
System.String name

The name of the field.
System.String expression

The expression. See the Grid User's Guide for expression syntax and examples.
System.Type resultType

The result type.

Properties

DefaultValue

Not used for expression fields.

Declaration
public string DefaultValue { get; set; }
Property Value
Type
System.String

Expression

Gets or sets the formula expression. See the Grid user's guide for syntax and examples.

Declaration
public string Expression { get; set; }
Property Value
Type
System.String

MappingName

Not used for expression fields.

Declaration
public string MappingName { get; set; }
Property Value
Type
System.String

ReadOnly

Gets or sets the ReadOnly for expression fields.

Declaration
public override bool ReadOnly { get; set; }
Property Value
Type
System.Boolean
Overrides

ResultType

The result type that the expression should be converted to (default is System.String).

Declaration
public string ResultType { get; set; }
Property Value
Type
System.String

Methods

Clone()

Creates a copy of this descriptor.

Declaration
public override FieldDescriptor Clone()
Returns
Type Description
FieldDescriptor

Copy of this descriptor.
Overrides

CopyExpressionFieldMembersTo(ExpressionFieldDescriptor)

Used to copy the expression fields

Declaration
protected void CopyExpressionFieldMembersTo(ExpressionFieldDescriptor ed)
Parameters
Type Name Description
ExpressionFieldDescriptor ed

ExpressionFieldDescriptor

DetermineReferencedFields()

Returns an array of field descriptor names that the expression references.

Declaration
protected override string DetermineReferencedFields()
Returns
Type Description
System.String

Returns array of field descriptor names.
Overrides

Equals(Object)

Compares this descriptor with another descriptor.

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
System.Object obj
Returns
Type Description
System.Boolean

True if both the descriptors are equivalent; False otherwise.
Overrides

GetCompiledExpression()

Gets a string that holds pre-compiled information about the expression.

Declaration
public string GetCompiledExpression()
Returns
Type Description
System.String

A string that holds pre-compiled information about the expression.

GetHashCode()

Serves as a hash function.

Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32

Returns the hash code.
Overrides

GetPropertyType()

Gets the property type.

Declaration
public override Type GetPropertyType()
Returns
Type Description
System.Type

Property type.
Overrides

GetValue(Record)

Calculates the expression result value for the specified record.

Declaration
public override object GetValue(Record record)
Parameters
Type Name Description
Record record

The Record.
Returns
Type Description
System.Object

The Value of the record.
Overrides

InitializeFrom(FieldDescriptor)

Creates a new expression field descriptor from another descriptor.

Declaration
public override void InitializeFrom(FieldDescriptor other)
Parameters
Type Name Description
FieldDescriptor other

Field descriptor which is used to create the new descriptor.
Overrides

ResetCompiledExpression()

Resets the compiled expression. It will be recompiled later on demand.

Declaration
public void ResetCompiledExpression()

ResetExpression()

Resets the formula expression to empty.

Declaration
public void ResetExpression()

ResetResultType()

Resets the result type to System.String.

Declaration
public void ResetResultType()

ShouldSerializeResultType()

Determines if ResultType was modified.

Declaration
public bool ShouldSerializeResultType()
Returns
Type Description
System.Boolean

True if the content was modified; False otherwise.

Implements

System.ComponentModel.ICustomTypeDescriptor
System.IDisposable
System.ICloneable