TclJSONValue

The TCLJSONValue represents the fundamental data element within the TCLJSON library. It serves as a strongly typed container for all supported JSON data types, including string, number, boolean, null, and datetime.

Feature	Use of	Definition
Create(AValue: TJSONValue)	val = TCLJSONValue.Create(SomeJSONValue);	Initializes a TCLJSONValue instance by wrapping an existing TJSONValue reference.
AsString	text = val.AsString;	Returns the stored value as a string if its type is string-compatible.
AsInteger	num = val.AsInteger;	Converts and retrieves the value as an integer type.
AsFloat	fnum = val.AsFloat;	Retrieves the numeric value as a floating-point number.
AsBoolean	flag = val.AsBoolean;	Returns the stored value as a boolean (True or False).
AsDateTime	dt = val.AsDateTime;	Retrieves the stored value as a TDateTime object if it represents a date/time.
IsNull	val.IsNull	Checks whether the current value is null.
IsString	val.IsString	Returns True if the value is a string type.
IsNumber	val.IsNumber	Returns True if the value is numeric (integer or float).
IsBoolean	val.IsBoolean	Returns True if the value represents a boolean type.
IsDateTime	val.IsDateTime	Returns True if the stored value is a date/time type.
ToString	jsonText = val.ToString;	Converts the internal value to its JSON-compatible string representation.
GetValueByPath	childVal = val.GetValueByPath('data.user.name');	Retrieves a nested JSON value using dot notation within a hierarchical structure.
Str	val = TCLJSONValue.Str('Hello');	Creates a TCLJSONValue instance representing a string type.
Num	val = TCLJSONValue.Num(25.75);	Creates a TCLJSONValue instance containing a floating-point number.
Int	val = TCLJSONValue.Int(100);	Creates a TCLJSONValue instance representing an integer number.
Bool	val = TCLJSONValue.Bool(True);	Creates a TCLJSONValue instance representing a boolean value.
DT	val = TCLJSONValue.DT(Now);	Creates a TCLJSONValue instance containing a TDateTime value.
Null	val = TCLJSONValue.Null;	Creates a TCLJSONValue instance representing a null JSON value.

Important: Data Type

Avoid mixing data types when reading or writing JSON values; each accessor (AsString, AsFloat) must correspond to the original type.

Example: TCLJSONValue in Use

var
  MyForm: TClForm;
  InputEdt: TClProEdit;
  StrBtn, NumBtn, BoolBtn, CheckBtn, ClearBtn: TClProButton;
  OutputMemo: TClMemo;
  JVal: TCLJSONValue;

void CreateStringValue
{
  JVal = TCLJSONValue.Str(InputEdt.Text);
  OutputMemo.Lines.Text = 'String Value: ' + JVal.AsString;
}

void CreateNumberValue
{

  JVal = TCLJSONValue.Num(StrToFloat(InputEdt.Text));
  OutputMemo.Lines.Text = 'Number Value: ' + FloatToStr(JVal.AsFloat);
}

void CreateBooleanValue
var
  inputLower: string;
{
  inputLower = LowerCase(Trim(InputEdt.Text));
  if ((inputLower == 'true') || (inputLower == '1') || (inputLower == 'yes'))
    JVal = TCLJSONValue.Bool(True)
  else
    JVal = TCLJSONValue.Bool(False);

  if (JVal.AsBoolean)
    OutputMemo.Lines.Text = 'Boolean Value: True'
  else
    OutputMemo.Lines.Text = 'Boolean Value: False';
}

void CheckValueType
var
  info: string;
{
  if (JVal.IsNull)
    info = 'Type: Null'
  else if (JVal.IsNumber)
    info = 'Type: Number'
  else if (JVal.IsString)
    info = 'Type: String'
  else if (JVal.IsBoolean)
    info = 'Type: Boolean'
  else if (JVal.IsDateTime)
    info = 'Type: DateTime'
  else
    info = 'Unknown type';

  ShowMessage(info);
}

void ClearValue
{
  JVal = TCLJSONValue.Null;
  OutputMemo.Lines.Text = 'Value cleared (Null)';
}

{
  MyForm = TClForm.Create(Self);

  InputEdt = MyForm.AddNewProEdit(MyForm, 'InputEdt', 'Enter a value...');
  InputEdt.Align = alTop;
  InputEdt.Height = 35;
  InputEdt.Margins.Left = 10;
  InputEdt.Margins.Right = 10;
  

  OutputMemo = MyForm.AddNewMemo(MyForm, 'OutputMemo', 'Output');
  OutputMemo.Align = alClient;
  OutputMemo.Height = 150;
  OutputMemo.Margins.Left = 10;
  OutputMemo.Margins.Right = 10;
  OutputMemo.TextSettings.WordWrap = True;

  StrBtn = MyForm.AddNewProButton(MyForm, 'StrBtn', 'Create String Value');
  StrBtn.Align = alBottom;
  StrBtn.OnClick = 'CreateStringValue';

  NumBtn = MyForm.AddNewProButton(MyForm, 'NumBtn', 'Create Number Value');
  NumBtn.Align = alBottom;
  NumBtn.OnClick = 'CreateNumberValue';

  BoolBtn = MyForm.AddNewProButton(MyForm, 'BoolBtn', 'Create Boolean Value');
  BoolBtn.Align = alBottom;
  BoolBtn.OnClick = 'CreateBooleanValue';

  CheckBtn = MyForm.AddNewProButton(MyForm, 'CheckBtn', 'Check Value Type');
  CheckBtn.Align = alBottom;
  CheckBtn.OnClick = 'CheckValueType';

  ClearBtn = MyForm.AddNewProButton(MyForm, 'ClearBtn', 'Clear Value');
  ClearBtn.Align = alBottom;
  ClearBtn.OnClick = 'ClearValue';

  MyForm.Run;
}

Output:

See Also

• TclJSONArray
• TclJSONObject
• TclJSONPair
• TclJSON