EqExpression class

December 9, 2019

Represents common expression object.

public abstract class Korzh.EasyQuery.EqExpression

Fields

Type Name Description
String _text This field contains expression's text

Properties

Type Name Description
EntityAttr Attribute Gets or sets the attribute.
String CustomFunc Gets the custom func for expression if defined
DataType DataType Gets or sets the data type.
String Hint Gets or sets the expression hint.
Boolean IsAggregate Gets a value indicating whether this expression is aggregate.
DataKind Kind Gets the expression kind.
DataModel Model Gets the model.
Type SystemType Gets the system type for this expreesion (it's used in LINQ query builder)
Int32 Tag Get the expression's tag - a special identifier that is used to distinguish the type of the expression .
String Text Gets or sets the expression text used for visual representation.
String Value Gets or sets the value of expression.

Events

Type Name Description
EventHandler ContentChange This event is raised after expression was changed

Methods

Type Name Description
void AssignExpr(EqExpression expr) Assigns some expression to this one. This method just does nothing in the base class but can perform some actions in Expression descendants.
void ContentChanged() Invoke ContentChange event
void LoadFromXmlReader(XmlReader reader) Loads expression from XML.
void OnContentChange(EventArgs e) Raises the ContentChange event.
void ReadOnePropFromJson(JsonReader reader, String propName) Reads one expression property from JSON.
Task ReadOnePropFromJsonAsync(JsonReader reader, String propName) Reads one expression property from JSON (asynchronous way).
void SaveToXmlWriter(XmlWriter writer, String xmlTagName) Saves expression to XML writer.
void SaveToXmlWriter(XmlWriter writer) Saves expression to XML writer.
void SetContent(String val, String txt) Sets the content of the expression (both its value and text).
void SetContentSilent(String val, String txt) Sets the content of the expression silently (without calling ContentChanged event).
String TagToOldClassName(Int32 tag) Converts the expression's tag value to the name of old expression class (like "CONST" or "ENTATTR").
void WritePropertiesToJson(JsonWriter writer) Writes all experssion properties to JSON. This method must be overriden in the descendant classes
Task WritePropertiesToJsonAsync(JsonWriter writer) Writes all experssion properties to JSON (asynchronous way). This method must be overriden in the descendant classes
void WriteToJson(JsonWriter writer) Write the content of the expression to JSON
Task WriteToJsonAsync(JsonWriter writer) Write the content of the expression to JSON (asynchronous way).
void WriteXmlTagStart(XmlWriter writer) Writes the expression XML tag start.
void WriteXmlTagStart(XmlWriter writer, String tagName) Writes the expression XML tag start.

Static Fields

Type Name Description
IList<IExpressionCreator> Creators

Static Properties

Type Name Description
String XmlTagName Gets the name of the XML tag used for representation of Expression (an all its descendants) object in XML files.

Static Methods

Type Name Description
String ApplyCustomFunc(String func, String expr) Applies the custom function.
EqExpression Create(DataModel model, Int32 tag) Creates the expression instance of specified type.
EqExpression CreateByClassName(DataModel model, String className) Creates the expression instance of specified class (type) name.
EqExpression ReadFromJson(DataModel model, JsonReader reader) Reads one expression from JSON. This static function recognizes the expression type and creates an instance of appropriate class.
Task<EqExpression> ReadFromJsonAsync(DataModel model, JsonReader reader) Reads one expression from JSON.(asynchronous way). This static function recognizes the expression type and creates an instance of appropriate class.
Boolean RegisterCreator(IExpressionCreator creator) Registers new type of expression.