Get field value

This section explains the basics of getting field values ​​for a model.

Metamodel definition and field value type

In Next Design, the model holds field values ​​in the C# language data type that corresponds to the field type defined in the metamodel. The relationship between the field type and the C# language data type exposed by the API is as follows.

Field Type	C# language data type
String	string
Integer	int
Double	double
Boolean	bool
Enum Type	IEnumLiteral
Rich text type	*1
Class type (singular)	IModel
Class type (plural)	IModelCollection

*1

The rich text type is held in a special data format that holds multiple texts for each format (text|html|xaml). This data format is not exposed in the API. Most APIs for retrieving field values ​​use unformatted plain text as the string type. To handle rich text field values ​​with formatting, see Working with Rich Text Fields.

The API exposes several methods in the IModel interface to retrieve model field values.

Method	Description
GetField, GetFieldAt	Can be used to retrieve the C# data type exposed in the API. For details, see here.
GetFieldString, GetFieldStringAt	Can be used to always retrieve the field as a string, regardless of the field type. For details, see here.
GetFieldValues	Can be used to retrieve a model collection of class-type (multiple) field types. For details, see here.
GetRichTextField	Can be used to specify a format and obtain a rich text type field value. For details, see here.

Obtaining as an object type

To obtain a field value as an object type, use the GetField method of the IModel object. The actual object type obtained will vary depending on the type of the metamodel field, so you will need to cast it before using it. The relationship between the field type and the C# type is as follows:

Field Type	C# type to which object can be cast
String	string
Integer	int
Double	double
Boolean	bool
Enum Type	IEnumLiteral
Rich Text Type	string *2
Class Type (Singular)	IModel
Class Type (Plural)	IModel *3

*2

When the GetField method is called for a rich text type field, plain text without formatting is obtained as a string type.

*3

When the GetField method is called for a class type field with a multiplicity of 2 or more, the first model of the corresponding field is obtained. If you want to obtain a model other than the first, specify a 0-based index with the GetFieldAt method, or obtain a collection of models using the GetFieldValues method.

public void GetField(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 

//If the field name is "SomeField" 
object someFieldValue = model.GetField("SomeField"); 

//... 
} 

Get as string type

Field values ​​can be obtained as strings regardless of the field type. To get as string type, use the GetFieldString method of the IModel object. The relationship between the field type and the string that can be obtained is as follows.

Field Type	String that can be obtained
String	String of the field value
Integer	String representation of the field value (integer)
Double	String representation of the field value (real number). Depending on the value of the real number, it may be expressed in exponential notation.
Boolean	"True" or "False"
Enum Type	Name of enumeration literal
Rich Text	Plain text without formatting
Class Type (Singular)	Model name
Class Type (Plural)	Model name *4

*4

When the GetField method is called for a class type field with a multiplicity of 2 or more, the first model name of the field is obtained. If you want to obtain a model other than the first, specify a 0-based index with the GetFieldStringAt method.

public void GetFieldString(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 
string someFieldValue = model.GetFieldString("SomeField"); 

//... 
} 

Get the literal value of an enumeration

In NextDesign, enumeration field values ​​are stored as enumeration literal types (IEnumLiteral). The literal value of an enumeration can be obtained as an object type using the GetField method of the IModel object, then cast to an enumeration literal type (IEnumLiteral) and obtained using the Name property of the IEnumLiteral object.

public void GetField(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 
IEnumLiteral someFieldValue = model.GetField("SomeField") as IEnumLiteral; 

if (someFieldValue == null) 
{ 
c.App.Window.UI.ShowMessageBox("Not an enumeration field value."); 
return; 
} 
c.App.Window.UI.ShowMessageBox($"SomeField literal: {someFieldValue.Name}"); 

//... 
} 

note

You can also get the literal value directly by using the GetFieldString method of the IModel object.

Get boolean value

To get boolean value, use GetField method of IModel object to get object type, then cast to boolean type.

public void GetField(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 
bool? someFieldValue = model.GetField("SomeField") as bool?; 

if (!someFieldValue.HasValue) 
{ 
c.App.Window.UI.ShowMessageBox("Field value is not boolean type."); 
} 

//... 
} 

Get model

If the field type is a single class type, use GetField method of IModel object to get object type, then cast to IModel type.

public void GetField(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 

//If the field name is "Actor" 
IModel actor = model.GetField("Actor") as IModel; 

if (actor == null) 
{ 
c.App.Window.UI.ShowMessageBox("Not a class type field value."); 
} 

//... 
} 

If the field type is a multiple class type (the upper limit of multiplicity is not 1), you can get the model at any position by specifying a 0-based index with the GetFieldAt method of the IModel object. The GetFieldAt method returns a value of type object, so cast it to type IModel. The number of field values ​​can be found with the Count method of the IModel object.

public void GetFieldAt(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 

//If the field name is "Usecases" 
var count = model.Count("Usecases"); 
if (count > 0) 
{ 
//Get the model at the end of the field 
//The index is 0-based 
var index = count - 1; 
IModel usecase = model.GetFieldAt("Usecases", index) as IModel; 
} 
} 

Get a collection of models

If the field type is a multiple class type (the upper limit of multiplicity is not 1), you can get a collection of models by using the GetFieldValues method of the IModel object.

public void GetField(ICommandContext c, ICommandParams p) 
{ 
IModel model = c.App.Workspace.CurrentModel; 

//If the field "SubComponents" is a collection of models 
IModelCollection subComponents = model.GetFieldValues("SubComponents") ; 

//subComponent is of type IModel 
foreach (var subComponent in subComponents) 
{ 
var someFieldValue = subComponent.GetFieldString("SomeField"); 
//... 
} 
}